R12a Evacuation/Recharge

[caseyrstewart]

Greetings,

 

I was curious if anyone could help me with my AC system. I have a brand new condenser, dryer, and know for sure the compressor works. I recently bought a manifold and evacuated the system, then added a can of Red Tek Oil Charge, Leak Stop, and a couple cans of refrigerant. I still can't seem to get the system over 20 PSI. Regardless of how much R12a I add, it plateaus at 20. Does this mean I have a leak? Thank you in advance!

[Minuit]

We're going to need a lot more info here. A/C is not something you can just dive into, it's a precise field and we need all of the details you can give us. Have you ever worked on automotive A/C before? What year and engine is the vehicle? Has the system been previously converted to R-134a or is it a virgin R-12 system? Did the system hold ~30 inHg vacuum for at least one hour? Did you remember to open up the service valves? How do you know the compressor works? Did you verify that there isn't a bunch of metal shavings in the system? What brand are these manifold gauges? Are you familiar with how to use them? Is this 20 PSI on the high side, low side, or both? Is the compressor engaging? I am assuming here that it is not engaging.

 

Did you open the service valves? Those have to be manually opened after the gauges are connected. The can should get cold and stay cold while you're attempting to charge. If it isn't getting cold and staying that way, the system is not taking refrigerant.

 

Before you do anything else, you need to stop shoving stuff blindly into the system. You charge by weight, not pressure. Get a scale. A food scale is fine. Add oil with an oil injector, or if you hate yourself, by pouring oil into the service hose a little at a time. Measure that out too. I hate those stupid oil charge cans. Replacing the condenser and drier will require more oil than is in one of those anyway. What type of oil and what viscosity was in the oil charge cans?

 

Also, I wish you wouldn't have stop leaked your system. It's tainted for life now. Hopefully you just forgot to open the service valves and none of it actually made it into the system. If you have a leak, you have to find it and fix it properly.

 

I don't know what this R-12a stuff is, but I imagine it's probably some blend of hydrocarbons that hopefully mixes with mineral oil. There will be a charge weight conversion factor for it. With R-134a, the charge weight is roughly 80% of the R-12 charge weight. I don't know what it is for R-12a, but you have to weigh it out. It should say on their materials somewhere what that conversion factor is. If not, it's even sketchier than I thought.

 

I think there's something else going on here. If you can't keep the system above 20 psi you have a GROSS leak that would be shooting refrigerant all over the place and it would probably be pretty loud. With all of the stuff you put in there you should have more than 20 psi, again assuming that this is a static reading and that the compressor does not engage.

 

If the compressor is engaging and you see a low side pressure of 20 psi with the compressor running, that's an entirely different situation. Once again, with A/C you really need to tell us everything you can tell us. Better yet, take a video of what's going on on the gauges and with the truck.

[caseyrstewart]

To answer your questions, yes. I have worked on AC systems before. I'm by no means an expert but have a basic understanding of how they work.

 

I have a 1987 Comanche. Straight 6 4.0 liter engine. It is a virgin R12 system. I ran the vacuum test for an hour. The system dropped to around 27-28 Hg. Perhaps that's part of the issue, but I felt that was close enough to attempt a recharge (correct me if I'm wrong). I opened up both service ports for the evacuation and closed the high pressure side for the recharge. I know the compressor works because it's currently engaging. 20 PSI is on the low pressure side. It's a Harbor Freight manifold and yes, I know how to use it. 

 

Also worth noting, the system blows cold. For all intensive purposes, the AC is currently functional. There are no visible leaks and the pressure holds at 20 PSI. It just won't go above that number. As far as the R12a stuff goes, it's made by a Canadian company called Red Tek. There are several posts on Comanche Club forums about it and people seem to have good results using it. From what I understand, it is a blend of hydrocarbons as you've stated.

[gogmorgo]

I've used the R12a successfully a couple times. It's billed as being a "universal" refrigerant, for any system, and I have used it in both r12 and 134 systems. The SDS lists it as "alkanes", which typically refers to propane but with whatever other herbs and spices got added in. The completely uncited wiki page on "hc12a" talks about isobutane as well. https://en.wikipedia.org/wiki/HC-12a.

IIRC the package had directions for proper use, and conversion rates, but without proper equipment (the "kit" that comes with it is just a valve and pressure gauge so there was no way to evacuate the system) it kinda turns into "just shove it in with whatever else is in there until you hit the target pressure". And that method lasted five years in one r12 van we had before the vehicle was scrapped. Not "proper", I know, but it worked. ¯\_(ツ)_/¯ 

[dasbulliwagen]

You want to see around 30 PSI or so on the low side and around 250 PSI or so on the high side. If you were seeing 20 PSI on the high side I don't think your system would be cooling. When I converted mine to 134a, I found it took MORE refrigerant that I thought it would to get to proper pressures. Maybe you just need to add more to the system and keep an eye on the presssures while doing it until you get a little more on the low side.

[Minuit]

Alright, @caseyrstewart, let's go in order of what you said.

 

Dropping 3 inHg in an hour is a considerable leak somewhere between the manifold gauges and the atmosphere. A "solid" system should be able to hold 30 over night if the gauges are also leak-free. If it's in your system, it's a considerable leak, and it'll probably vacate the charge within a few weeks at that rate. I doubt the stop leak product will fix it, and if it does, I very much doubt it will be a permanent fix. If I were working on this system, I would want to get the stop leak out as fast as I could and start over.

 

The correct way to find out where the leak is is by using UV dye. The dye mixes with the oil and will accumulate around the leak. For a large leak, it's visible with the naked eye, but smaller leaks will require a UV light and UV-blocking glasses to see for sure.

 

You indicated a 20 PSI low side pressure. Let me just get this out of the way - charging by pressure in an automotive system is bull$#!&. Charging by low-side pressure only is even stinkier bull$#!&. The instructions that Red Tek provide are on the level of those "A/C PRO INSTANT FIX MEGA ULTRA ICE" cans of garbage from Autozone, and I'm sorry that those crappy, borderline dangerous instructions were what you had to go by and you thought you were doing a good thing by following them. In automotive systems, we charge by weight. These specs are usually fairly easy to find on the internet. If we're using a different refrigerant than the original, the charge weight will be the original multiplied by a conversion factor that depends on the refrigerant.

 

I don't have an '87 FSM handy, but the number I found for your system was 36oz of R-12 and 8oz of mineral oil. Red Tek's conversion factor is 0.33 oz of their stuff to one oz of R-12. That means you need one pound of 12a (and my mistake, it's just "Red Tek 12a", it's not R-12a) in the system, so by pure luck you're probably at about the right charge weight including the other things you added, maybe slightly overcharged. You'll lose some in the gauges, so you're probably at approximately the right charge.

 

Now, an expansion valve system like our MJs have should be very good about keeping the compressor running. My '91 will keep the compressor on almost all of the time at high fan speed. Does it stay running, or does it cycle the compressor? Some cycling is fine, but it should be able to keep the compressor running especially at high fan speed.

 

To glean any real information on how the system is running we need the high side pressure too. In the future, tell us both of these pressures. In fact, that's where your cooling comes from - the pressure drop at the expansion valve. With the compressor on, what are you seeing on the high side gauge? We'll also need to know the ambient temperature, and it's best if you give us this reading with the engine as cool as possible. This number DEPENDS on the temperature, so we really need to know that

 

 

[Minuit]

3 hours ago, dasbulliwagen said:

You want to see around 30 PSI or so on the low side and around 250 PSI or so on the high side. If you were seeing 20 PSI on the high side I don't think your system would be cooling. When I converted mine to 134a, I found it took MORE refrigerant that I thought it would to get to proper pressures. Maybe you just need to add more to the system and keep an eye on the presssures while doing it until you get a little more on the low side.

 

250 PSI... at what temperature? With what refrigerant? If I saw 250 PSI on a 134a system when it's 90 degrees outside, that's a perfectly good pressure. If it was 65, different story entirely. If it was 110, that's a probable undercharged system. I did the math for the OP and found that he's approximately at system capacity considering the refrigerant he is adding. Continuing to add more refrigerant will quickly overcharge his system.

 

I looked at the OP's post history and found that he's located about an hour from me. Neat. My fitbit tells me it's 75 today. 250 PSI is very high for 75F ambient on R-134a, and if he were on R-134a that number would indicate a significantly overcharged system or poor condenser performance. Please don't tell people to overcharge their system.

[caseyrstewart]

Hey @Minuit thank you for all of that information. I'm learning that a lot of people have differing opinions on what works and what doesn't, but like most car work, there is a right and wrong way to do something. I think I have taken some bad advice, which is fine. Live and learn.

 

Ultimately, this is not my daily driver. It's a truck I use to haul my kayak out to the lake and pick up top soil from Home Depot. If the air doesn't work, that's ok. If it does, great! 

 

I've always heard using UV dye is harmful to the system. Is that true or is that a myth? At this point, I will probably evacuate the system once again, and add the dye in order to find my leak. You were right. It's already blowing warm so I assume most of my R12a has leaked out. Do you have any experience using compressed air to check for leaks? I've seen a few guys go that route. Also, when I add the dye, I'm assuming I'll have to add more refrigerant in order to get the compressor working, yes?

 

Once all this is done and I've found the leak, I'll start talking through a more precise recharge with a scale. For what it's worth, the only reason I didn't charge by weight last time is because I couldn't seem to find the specs for my particular Comanche. Thanks for your help so far! Really appreciate it!

[Minuit]

2 minutes ago, caseyrstewart said:

Hey @Minuit thank you for all of that information. I'm learning that a lot of people have differing opinions on what works and what doesn't, but like most car work, there is a right and wrong way to do something. I think I have taken some bad advice, which is fine. Live and learn.

 

Ultimately, this is not my daily driver. It's a truck I use to haul my kayak out to the lake and pick up top soil from Home Depot. If the air doesn't work, that's ok. If it does, great! 

 

I've always heard using UV dye is harmful to the system. Is that true or is that a myth? At this point, I will probably evacuate the system once again, and add the dye in order to find my leak. You were right. It's already blowing warm so I assume most of my R12a has leaked out. Do you have any experience using compressed air to check for leaks? I've seen a few guys go that route. Also, when I add the dye, I'm assuming I'll have to add more refrigerant in order to get the compressor working, yes?

 

Once all this is done and I've found the leak, I'll start talking through a more precise recharge with a scale. For what it's worth, the only reason I didn't charge by weight last time is because I couldn't seem to find the specs for my particular Comanche. Thanks for your help so far! Really appreciate it!

A/C work is not easy, and you should be commended for being willing to stop and learn now that you're starting to see how deep of a rabbit hole you've fallen into.

 

The UV dye will mix with the oil and circulate through the system. I've never heard of it causing problems in systems. In fact, a lot of factory charges (GM comes to mind) include dye. Once your system is proven to be solid, you don't need it anymore. Adding too much oil(or dye) will reduce the cooling capacity, and WAY too much oil can slug the compressor. It won't take much dye to show a leak. It's very, very concentrated. Just make sure you use dye for use in A/C systems, because it has to mix with the refrigerant and oil.

 

On a recent job on a friend's Chevrolet half-ton pickup, I used 1/4oz of dye in a system that holds 35 oz of R-134a and I believe 7 oz of oil. I told him to use the A/C as much as possible and come back when it stops working. It showed the leaks just fine, and the system is working great 3 weeks after fixing the leaks.

 

As for compressed air, I wouldn't. Compressed air will have some degree of moisture in it, and moisture is really bad for the system (that's the point of the receiver/drier, and why you should replace it immediately before the system is closed). Dry nitrogen is what I hear about being used most. If you don't have that, dye with the refrigerant is the most obvious way to pinpoint a leak. As much as I hate charging a system I know leaks, it's the best way if you don't have access to a cylinder of dry gas.

 

Yes, you'll need more refrigerant to get it working again. You're not going to get rid of the stop leak except by flushing every single component, so we're going to have to live with that I guess. If your air is warm again after only a couple of days, it's a big leak that will be very, very obvious using dye and a UV light. I'm having a hard time finding price info on this 12a stuff. Is it expensive? This kind of thing is why I honestly prefer 134a - I'll just tell a customer to stop by Walmart on the way here and pick up however much they need for $5 a can.

[caseyrstewart]

3 hours ago, Minuit said:

A/C work is not easy, and you should be commended for being willing to stop and learn now that you're starting to see how deep of a rabbit hole you've fallen into.

 

The UV dye will mix with the oil and circulate through the system. I've never heard of it causing problems in systems. In fact, a lot of factory charges (GM comes to mind) include dye. Once your system is proven to be solid, you don't need it anymore. Adding too much oil(or dye) will reduce the cooling capacity, and WAY too much oil can slug the compressor. It won't take much dye to show a leak. It's very, very concentrated. Just make sure you use dye for use in A/C systems, because it has to mix with the refrigerant and oil.

 

On a recent job on a friend's Chevrolet half-ton pickup, I used 1/4oz of dye in a system that holds 35 oz of R-134a and I believe 7 oz of oil. I told him to use the A/C as much as possible and come back when it stops working. It showed the leaks just fine, and the system is working great 3 weeks after fixing the leaks.

 

As for compressed air, I wouldn't. Compressed air will have some degree of moisture in it, and moisture is really bad for the system (that's the point of the receiver/drier, and why you should replace it immediately before the system is closed). Dry nitrogen is what I hear about being used most. If you don't have that, dye with the refrigerant is the most obvious way to pinpoint a leak. As much as I hate charging a system I know leaks, it's the best way if you don't have access to a cylinder of dry gas.

 

Yes, you'll need more refrigerant to get it working again. You're not going to get rid of the stop leak except by flushing every single component, so we're going to have to live with that I guess. If your air is warm again after only a couple of days, it's a big leak that will be very, very obvious using dye and a UV light. I'm having a hard time finding price info on this 12a stuff. Is it expensive? This kind of thing is why I honestly prefer 134a - I'll just tell a customer to stop by Walmart on the way here and pick up however much they need for $5 a can.

 

 

Well, I enjoy learning about this stuff. Hopefully next time I encounter the issue I'll have a little better understanding of how to fix it...

 

Copy that on compressed air. I just went to O'Reilly's and everything they have fro UV dye is for R-134 systems. I found this kit on Amazon and while it's not cheap, it seems like a good universal option:

 

https://www.amazon.com/UView-332010-Spotgun-Jr-LED-Lite/dp/B000NBVFOQ/ref=sr_1_31?crid=1TY8CVH19Z5XL&keywords=uv+dye+leak+detector+kit&qid=1560096513&s=gateway&sprefix=uv+dye%2Caps%2C138&sr=8-31

 

Also, here's a link to the Red Tek R12a. It breaks down to about $13 a can if you buy the 3 pack.

 

https://www.amazon.com/Cans-REDTEK-Refrigerant-Ounce-Can/dp/B00E5MOPEG/ref=sr_1_2?crid=2RD3R16X4CNHO&keywords=redtek+12a&qid=1560108789&s=automotive&sprefix=red+tek+%2Cautomotive%2C141&sr=1-2

 

Any final thoughts before I moved ahead?

[Minuit]

That dye kit will work. It'll have everything you need, including an injector. I have no idea if you can use it like a regular oil injector, but it would get the job done for just injecting dye - wouldn't be my first choice if you plan to work on A/C with any regularity though.

 

I use one of these for adding oil and dye. A little pricy, but it's a lot more flexible. You can fill it up with whatever you want and inject it into either an empty or charged system. To go with that, I bought a cheap kit at O'reilly with a UV light and some UV blocking glasses. They work fine.

https://www.amazon.com/FJC-2732-Hand-Turn-Injector/dp/B001T9AREK/ref=sr_1_6?keywords=fjc+oil+injector&qid=1560104546&s=gateway&sr=8-6#customerReviews

 

Also - there's a pretty good chance that you're low on oil, especially since you went from cold to warm air in a couple of days. If I were working on this system, before I did anything else I would remove the compressor and drain/refill it of oil, as a sanity check more than anything else. If there's no oil in the compressor at all (I've seen it once or twice), that's bad and you wouldn't have known if you didn't check. The condenser would've had about 1oz of oil in it, and the leak probably caused some oil loss as well. I don't know if the 5-cylinder Sanden compressors have the same problem, but the 7 cylinder compressors on the 91 and later trucks love to leak oil out of the front seal. After you fix the leaks (and as the very last step before you put the system into permanent service), you will want to replace the receiver-drier. When you do that, you'll want to add an additional ounce of oil.

 

Also, any time you disconnect an o-ring, replace it. Get an assortment of HNBR o-rings. I also like to go on RockAuto and order a couple of o-ring assortments for the vehicle in question, just to have some spares (and in case there's funny sizes of o-rings)

https://www.amazon.com/Performance-Tool-W5201-Ring-Assortment/dp/B0002KO1XK/ref=sr_1_3?keywords=hnbr+o+ring&qid=1560106667&s=automotive&sr=1-3

 

When you drain the compressor out, if there is more than a couple of ounces of oil in it, the FSM recommends adding one ounce more than you drained out. If there's a LOT of oil in it (like 6oz or more), the system has way too much oil in it and that's a problem too. It'll also get some of that stop leak out.

 

I'd recommend yanking the compressor off and doing this before you charge again, just to make sure the system HAD oil in it, and to make sure that the compressor has the best possible chance of living a long life. If the compressor is easy to remove (as it is on an MJ), I do this any time I'm working on a system that's new to me. Replacing the existing oil with new oil isn't a bad idea anyway.

 

A little too much oil won't hurt, but it will hurt the cooling efficiency a little. Too little oil is REALLY BAD and will turn your compressor into glitter in no time. Unfortunately, there's no dipstick for checking your A/C oil. Removing the compressor and draining/refilling it is the next best thing.

 

Since you're using 12a and it sounds like you want to keep using it, you'll add mineral oil to the system any time you add oil. That's what it would've originally come with, and IMO one of the few reasons to use it is that it will mix with the mineral oil. Here's a lifetime supply for 20 bucks.

https://www.amazon.com/ACDelco-15-117-Conditioning-System-Mineral/dp/B00171UV82/ref=sr_1_1?keywords=ac+mineral+oil&qid=1560105899&s=automotive&sr=1-1

 

$13 a can isn't as bad as I thought it would be, but you still won't want to blow through a full charge of it every week. Once you've done the above, vacuum it down again and charge with 2 cans of 12a and 1/4oz or so of dye and see if you can pick out where the leak is. More likely than not it'll be an o-ring on one of the connections.

[caseyrstewart]

Hmmm, ok. I'm honestly not sure how difficult it'll be to get my compressor out, but I guess at this point there's really no way of telling how much oil is in the system. If/when I get it removed, am I basing the amount that I put in only on how much is in that one part? Won't there be oil in the rest of the system or does that not matter as much?

 

Taking out the dryer makes sense. Everything I've read makes it sound like that part should be replaced every time a system is opened up and worked on. I've ordered the dye kit, more refrigerant, O-rings, and the mineral oil. Also, dumb question...is the mineral oil the only oil I'm adding to the compressor or is it in addition to a different type of a/c systems oil?

[Minuit]

On 6/9/2019 at 2:47 PM, caseyrstewart said:

Hmmm, ok. I'm honestly not sure how difficult it'll be to get my compressor out, but I guess at this point there's really no way of telling how much oil is in the system. If/when I get it removed, am I basing the amount that I put in only on how much is in that one part? Won't there be oil in the rest of the system or does that not matter as much?

 

Taking out the dryer makes sense. Everything I've read makes it sound like that part should be replaced every time a system is opened up and worked on. I've ordered the dye kit, more refrigerant, O-rings, and the mineral oil. Also, dumb question...is the mineral oil the only oil I'm adding to the compressor or is it in addition to a different type of a/c systems oil?

Should be easy peasy to get the compressor out. It's right on top. Remove the belt, remove the two lines (evacuate the system first), and the electrical connector. On my truck there is 4 bolts holding it on. I think it's the same on yours. And you're correct, this is my preferred way to get a glimpse at the system's health on an expansion valve system. You'll get a look at the oil level, oil cleanliness, and compressor health.

 

The compressor normally holds the most oil out of all of the components. It's distributed throughout the system (it circulates through the system with the refrigerant) and when there's no refrigerant left to carry it around it settles in a component. Out of a total system capacity of 8 oz of oil, I'd expect the compressor to have between a third and a half of it. As long as you drain more than a couple of ounces out of the compressor, I'd say not to worry. The FSM says to add an ounce more than you drained out, and I'd consider that a good rule of thumb.

 

You've read correctly. In an ideal world, you'd replace the drier every single time you open the system. You know that you've got at least one leak to fix, so it would be a waste of a drier to replace it when you know the system will leak itself empty in short order again.

 

The mineral oil is the only oil used in an R-12 system, and yes there is only one kind of oil in a given system. The compressor doesn't have an "oil tank" - it relies on the refrigerant to carry the oil through it. That's the only reason we have oil in the system - to lubricate the compressor as the refrigerant moves through it. That's the only type of oil in your system. Once the system is charged and in use, it all mixes together. As far as I can tell, the selling point of Red Tek 12a is that it mixes with any refrigerant oil, making it usable in even a virgin R12 system.

 

It's important to know, for anyone else who's reading this: the oil used depends on the refrigerant. Mineral oil mixes with R-12, which is why it's used in R-12 systems. When we moved over to R-134a, that caused a problem because R-134a does NOT carry mineral oil through a system. It has to use a different type of oil - usually, PAG oil but sometimes POE oil. There are a few different viscosities, which one is determined by the compressor.

[caseyrstewart]

@Minuit do you have any idea what this hose would be called if I ordered it at an auto parts store? As long as I'm tearing the system apart, I'd like to replace it (it's old/cracked and probably one of the older parts of the whole system).

 

IMG_7525 (1).HEIC

 

Going to take the compressor out today and check the oil level, then run the UV dye test. Here goes nothing...

 

[Minuit]

(what on earth takes images as a .heic file?)

 

The big hose running from the expansion valve to the compressor is what I assume you're talking about. It's called the suction line. I have my doubts that you'll be able to find it new. My '89 has something that looks similar, but I can't find that part number either.

[caseyrstewart]

10 minutes ago, Minuit said:

(what on earth takes images as a .heic file?)

 

The big hose running from the expansion valve to the compressor is what I assume you're talking about. It's called the suction line. I have my doubts that you'll be able to find it new. My '89 has something that looks similar, but I can't find that part number either.

 

It's an Apple "high efficiency" format...

 

Do you think something like this would work?

 

https://www.ebay.com/itm/A-C-AC-Hose-New-for-Jeep-Wrangler-Cherokee-Comanche-1987-1992-56002950-/132455523941?_trksid=p2349526.m4383.l4275.c10#viTabs_0

[Minuit]

Maybe. The part database I was looking at makes that look like a '90 and newer part. I really don't know.

[caseyrstewart]

Okay, so I was able to get the compressor out. Not an easy task as the bolts were VERY stuck, but with much time and patience, I was able to get it removed.

 

Now, let me ask this question...might it be worth it to just go ahead and replace the compressor for $300? I've spent enough money at this point to where I'd rather just do it right. Not to mention the air compressor looks very old and appears to have a refrigerant type of residue all over the bottom of it. I wouldn't be shocked if that's where my leak is coming from.

 

Also, for what it's worth there was approximately 1-2 ounces of oil that poured out of the compressor and it was diiiirty.

[Minuit]

13 minutes ago, caseyrstewart said:

Okay, so I was able to get the compressor out. Not an easy task as the bolts were VERY stuck, but with much time and patience, I was able to get it removed.

 

Now, let me ask this question...might it be worth it to just go ahead and replace the compressor for $300? I've spent enough money at this point to where I'd rather just do it right. Not to mention the air compressor looks very old. I wouldn't be shocked if that's where my leak is coming from.

Probably not a horrible idea to replace it. Was there anything in the oil that drained out?

 

The 7-cylinder Sanden compressors love to leak out of their front seal. Not sure about the 5-cylinder compressors, but I wouldn't be surprised if you were leaking out of the compressor somewhat.

 

I would never use a reman compressor in my own vehicle, but people do it all the time. If you have $300 to spend, you may be able to find an OEM Sanden compressor and that is what I would strongly prefer. Unfortunately, I have no freakin' clue what part number your compressor is. Is there a label on it?

[caseyrstewart]

1 hour ago, Minuit said:

Probably not a horrible idea to replace it. Was there anything in the oil that drained out?

 

The 7-cylinder Sanden compressors love to leak out of their front seal. Not sure about the 5-cylinder compressors, but I wouldn't be surprised if you were leaking out of the compressor somewhat.

 

I would never use a reman compressor in my own vehicle, but people do it all the time. If you have $300 to spend, you may be able to find an OEM Sanden compressor and that is what I would strongly prefer. Unfortunately, I have no freakin' clue what part number your compressor is. Is there a label on it?

 

There was no metal shavings that poured out, but the oil was definitely dirty. I measured approximately 1-2 ounces of fluid.

 

Ordered a new compressor and plan on putting it and the drier in Thursday when it arrives. Once installed, I'll run a new vacuum test to see if I can get it to hold at -30 Hg and go from there...

 

Man, thanks so much!! You've been a lifesaver so far!!

[Minuit]

8 minutes ago, caseyrstewart said:

 

There was no metal shavings that poured out, but the oil was definitely dirty. I measured approximately 1-2 ounces of fluid.

 

Ordered a new compressor and plan on putting it and the drier in Thursday when it arrives. Once installed, I'll run a new vacuum test to see if I can get it to hold at -30 Hg and go from there...

 

Man, thanks so much!! You've been a lifesaver so far!!

Only 2 oz (plus a little stays in the compressor as a film in the cylinders) would make me think it was slightly low on oil. Closer to 1 oz and I'd think it was quite low on oil. What brand of compressor did you buy?

 

Suggestion: don't replace the drier until you know it holds vacuum. That way, you won't waste the drier if it leaks. Yeah, you'll have to vacuum it again, but if it can hold a vacuum you have a pretty good chance that it'll hold refrigerant too. If it DOES leak, you're going to have to do the "charge with dye" routine until you find all of the leaks. Hopefully none of them are the evaporator.

[caseyrstewart]

13 hours ago, Minuit said:

Only 2 oz (plus a little stays in the compressor as a film in the cylinders) would make me think it was slightly low on oil. Closer to 1 oz and I'd think it was quite low on oil. What brand of compressor did you buy?

 

Suggestion: don't replace the drier until you know it holds vacuum. That way, you won't waste the drier if it leaks. Yeah, you'll have to vacuum it again, but if it can hold a vacuum you have a pretty good chance that it'll hold refrigerant too. If it DOES leak, you're going to have to do the "charge with dye" routine until you find all of the leaks. Hopefully none of them are the evaporator.

Is the evaporator what's behind the firewall?

 

Couldn't find an OEM Sanden so I bought a new Four Seasons compressor. Ok, thanks for the tip on the drier! I'll report back once I get the compressor in and pull a vacuum. Also, this may seem like a dumb question, but I just want to make sure...I don't have to add oil to a new compressor, do I? From what I understand, those come pre-oiled.

[Minuit]

27 minutes ago, caseyrstewart said:

Is the evaporator what's behind the firewall?

 

Couldn't find an OEM Sanden so I bought a new Four Seasons compressor. Ok, thanks for the tip on the drier! I'll report back once I get the compressor in and pull a vacuum. Also, this may seem like a dumb question, but I just want to make sure...I don't have to add oil to a new compressor, do I? From what I understand, those come pre-oiled.

The evaporator is inside your dash, yes. Real fun to replace. Been there, done that.

 

Sanden compressors come pre-oiled for a full system's oil capacity. That is too much in any case other than a fully new system. I don't know about Four Seasons, but you will want to at least know what is in that compressor. Drain and refill. You drained less than 2 fluid ounces of oil out of the old compressor. The FSM states to put in an ounce more than you took out, but I think you'll still be low on oil considering that. I'd probably put 3.5 oz in and not feel bad. Too little oil is really bad, a little too much isn't going to hurt. Remember, use mineral oil for this. Prior to charging, turn the compressor by hand about 10 revolutions. Any and all o-rings you disconnect during this process need to be replaced, always.

[caseyrstewart]

On 6/19/2019 at 9:34 AM, Minuit said:

The evaporator is inside your dash, yes. Real fun to replace. Been there, done that.

 

Sanden compressors come pre-oiled for a full system's oil capacity. That is too much in any case other than a fully new system. I don't know about Four Seasons, but you will want to at least know what is in that compressor. Drain and refill. You drained less than 2 fluid ounces of oil out of the old compressor. The FSM states to put in an ounce more than you took out, but I think you'll still be low on oil considering that. I'd probably put 3.5 oz in and not feel bad. Too little oil is really bad, a little too much isn't going to hurt. Remember, use mineral oil for this. Prior to charging, turn the compressor by hand about 10 revolutions. Any and all o-rings you disconnect during this process need to be replaced, always.

 

So the compressor finally arrived and on it was a sticker that says "190 mL of PAG 46" oil. Based on my research, that oil is designed to work with R-134a systems.

 

Did I buy the wrong compressor or do I just need to drain out the PAG 46 and put in the mineral oil in it's place?

[Minuit]

On 6/23/2019 at 6:14 PM, caseyrstewart said:

 

So the compressor finally arrived and on it was a sticker that says "190 mL of PAG 46" oil. Based on my research, that oil is designed to work with R-134a systems.

 

Did I buy the wrong compressor or do I just need to drain out the PAG 46 and put in the mineral oil in it's place?

I doubt that you can buy a new compresor with mineral oil in it these days. I'm guessing they are always expecting an R-134a conversion regardless of what the original system was.

 

Drain out as much of the PAG oil as possible and replace it with mineral oil. Turning the compressor as you drain it out will help get more out. You won't get it all, but you'll get most of it.

 

Before you add oil, tell me how much PAG oil came out of the replacement compressor. If it's a full system charge worth (6-8oz), add the 3.5 oz we discussed.