toid

Ok. it may not be there now. I haven't had to fix that part yet. HA Great little truck. Tough as nails, but an endless stream of "little" projects. Such is life... and jeeps. lol

what does the valve do? I'll have to check mine out to see if it's there. I can't say if it is.

There is a pale vacuum line under the water bottle... It comes through the firewall. It is right above the black that the AC lines go through before going through the firewall. Mine is dangling and dryrotted. Can anyone tell me what it is and where it connects so I can run a new line? Thanks. Rev. Toid

I am learning by leaps and bounds.

That could be the first time I ever saw the word "finagling" actually spelled. If it has an overflow hose how does it hold pressure?

Ain't hijacking no threads here, but I HAVE to ask... What oil filter and bottom end knock have n common? I'm assuming lower oil pressure due to overly restrictive filter design not allowing "floating" on the bearings.

Do I burp via the temp sensor with it running?

@Tugalo: could you provide me with some details on the bottle? what model vehicle or some details that I can use to find what you have. also did you use a 16 pound radiator cap or whatever radiator cap came with the bottle?

I haven't "filled" it, but I did fill it a bit beyond half. Now that u mention it, after the boiling and the overflowing, I ran it up to temp and parked a few times (I only live a mile or so from work) my coolant level is is at "half full bottle". I'm really considering a cooling conversion. This is aggravating. I flushed the system with off the shelf prestone product twice and the water flowing out of the radiator hose didn't seem restricted to me. When I changed the tstat, the water jacket behind the tstat on the head and tstat housing looked really good so I imagine the radiator passages were cleaned well enough. But I'm no pro in that area. Rev. Toid

More and more. She always wants more. Oh well, At least she not a Ford.

Tank referral? I will do all hoses n clamps at same time as the tank and a good burping.

I could very well be stupid. Its not unusual. So please correct me if I'm not seeing it right.

I may be experiencing ignorance here. Is the cap supposed to totally seal the bottle or isn't it designed to seal up to a particular level of pressure at which point steam/ fluid is allowed to bleed off? If a bad hose is allowing depressurization which causes boiling and the resultant steam, shouldn't I expect the cap to vent the risen steam/water to prevent something from rupturing?

Ok. Any favorite bottle selection... Or is it a stealership-only item?

OK. Got it done. As Cruiser requested... Here's the update. I replaced the tstat as I said last time. I put the Napa cap on the bottle. Nice fit. I pressure washed my fins up front to make sure airflow is good. Had a cooler week last week and today was the first scorcher we had. Ran to town with AC blasting. Temp got to 210 -a sliver over the mark actually. Pulled in the driveway and after about 45 seconds a slight boiling began. It carried on for less than 4 mins and lost less than a full cup of coolant. Heard a slight pressure sound... Couldn't tell if it was sucking or blowing but it was where the heater hose branches to the bottle. First time I noticed that hose hissing. There was water dripping from the tank cap but none visably discernable from the hose. By the quality advice I received here, my logic tells me to check/replace these hoses. If not a fix, then I burn my truck to the ground and dance around it like a wild Indian. (No offense to our native american members) Any other advice? Rev. Toid

OK Ok I cannot blame this one on Cheap Chinese rad caps. Unless the caps that are labeled, "Motorad Germany" are Chinese as well. I changed my tstat. When I took off my coolant tank cap the pressure piece inside the threaded cap part came apart and the threads on the cap would barely grab the tank and would not hold under even slight pressure when I tried to screw it down. I ordered a new one this am and will have it installed by lunch tomorrow. I drilled 2 holes in the tstat at 12/6 as suggested. No bubbles nor such in or around tank when I started and ran it up to operating temp. Water level rose a bit but tank didn't drain back down when it cooled.

I am assuming that because none of my hoses are leaking that they are holding pressure. but I have owned enough Ford products to know that just because it makes sense does not make it true.

Of course my tstat ain't got no jiggle valve. What size is that hole?

I have read (literally dozens) of forum threads about coolant boiling. Mine is little different from the rest of them and I have done most all of what was recommended... Is there anything I am missing? I have a few questions too. 1990 comanche 4.0 - closed system of course. It's flippin' HOT here in GA. 90+ (plus the index). Jeep runs 195(ish)-210. Only gets over 210 mark by a sliver if Idling with AC on for longer than a few minutes, but not much over. Coolant is boiling affter I shut off. I purchased a new fan clutch. I assume it's working properly but I couldn't tell you for sure, I have read of brand new ones being bad. coolant and oil both look "normal" and no boiling when running. I flushed the coolant system twice with parts store prestone flush one afternoon according to the instructions. AND I have a brand new plastic tank cap (whatever the AP store called "stock" pressure). I have a new T-stat and gasket but haven't had time to change it yet. I honestly don't know if I "bled" the air out correctly. I read that I was start cool, uncap the tank, watch for bubbles, fill back what goes down. wash, rinse, repeat unti no bubbles. Am I missing something? The water pump is flowing / no leaks there and the secondary (elec) fan is doing its thing. How do I know if my new fan clutch is functioning, and how do I know if I need further burping? Help would be appreciated. Rev. Toid Quick edit: It doesn't boil every time, just if I run AC and it gets right there at the 210 mark, and It never loses much coolant when it boils. Maybe 1/4 - 1/3 cup boils out.

I had a thought today. It almost HAS to be 12 in the system because, label or no label, I should have deduced by the fact that the fittings were not 134 fittings. Straight up 12 fittings. DUH. STILL, If I'm re-compressor-ing Ima do the right thing and upgrade. Thanks, guys! People helping people just because they can: doing unto others kindly as it was done unto them. DANG! Why can't the rest of the world be like a enthusiast forum? Now if you could fix my slightly choppy idle... (he says as he goes to another thread) Rev. Toid

Thanks. I am shopping around now. Although, I'm gettting pretty good prices at the local O'reiley's. Overall total on the stuff I need is cheaper than the online vendors so far. I tried a search and then some digging, but couldn't find any stock hoses for my truck that were listed as being suitable for 134... that is to say "barrier" hoses, but you say this place in Fla will make me some? How much did they run you, If I may ask? My stock ones are about 55 bucks apiece. Thanks Chris

Do the replacement compressors work as well with the 134a as they do with the R12 they were designed to work with? I got a fellow minister who runs a big shop locally who does the fancy AC flushing, etc. He said he'd be glad to get it done for me. I can do the install work and save that little bit of labor. I just need a little help with my parts selection. You say the stock 12 hoses are not exactly designed to contain the 134 refrigerant? Are there 134-compatible hoses available to replace mine? Or at least a crossover part that will fit, ie. a later model Cherokee? I'm ignorant and too broke for parts-trial-and-error. THANKS!! Rev. Toid

I couldn't find a "search this forum" feature so I tried the google method and didn't find exactly what I needed to know: I'd be grateful for a link. I'm sure there is one as mine is probably a common problem. I'd asked of another forum but have got no help. I recently repaired/recharged the AC in my 90 4.0 after 2 or 3 years of not being used (if what the PO told me was right). There was no upgrade information posted anywhere and I believe the PO mentioned that the last time he recharged the AC he couldn't do it himself. This leads me to believe it was still R12. My mechanic friend & I went to evac gas and there was only a minute amount of pressure present. I replaced Orings until it held vacuum and oiled/charged with R12. Plenty cold the last week and performed without any noise nor hitches but today I discovered a "growling" noise, intermittant (about 85% present) and it seems to be coming from AC compressor as it stops when AC is turned off. An Internet search presents the popular opinion that the compressor is failing. If not so what are my possibilities for repair? Could this be due to me unwittingly crossing up a 134 system with R12? Regardless, If my compressor is failing I will need another and I will go with 134a upgrade. All that to ask this: Since I'm going to upgrade & I'm compressor shopping, do I go back with a stock one? OR is there one more compatible with the 134 that is a direct replacement? I have read a dryer & Expansion Valve replacement is mandated for most compressor warrantees and I also plan to replace the lines. Is there anything else I need to do? Don't know that much about AC... to me it may as well be magic. Any experienced advice / recommendations appreciated. thanks! Rev. Toid

Yes. By all means... The "BS" has left the building.