To those with working A/C in their MJ...

[Minuit]

... how loud is your compressor? Because I'm not sure I'm supposed to hear it from inside the truck and feel vibrations in the floor at idle.

 

I ask because I just got done doing a complete system rebuild - new lines, condenser, receiver/drier, expansion valve, and a brand new genuine Sanden compressor. The parts are all for a '96 XJ and It has the correct amount of oil and contains the correct 32oz charge of R-134a. The system seems to cool pretty well. It's just that the compressor seems louder than it should. It's quieter than the original compressor was back when that system was working, but not by much. I do recall that the original compressor made a very similar sound.

 

Here's a crappy video of the A/C cycling. Skip to 0:30 to hear what I hear inside the truck. I had the e-fan unplugged so any noise you hear with the A/C clutch engaged is all from the compressor. The interior vibration I mentioned goes away above idle.

I've heard that Sanden compressors can be noisy, but is this in any way normal? I don't want to run the system if that noise is my brand new compressor turning itself into a fine mist of metal particles.

[grumpiebill]

It may have correct amount of oil...but what type of oil? Also verify system charge and amount of oil. Did the compressor come with oil in it and therefore could it be over charged with oil because we added more on top of what was already in the compressor...HTH

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[Minuit]

The compressor came with a full charge of SP-15 oil which as far as I can tell is equivalent to PAG 100. The instructions from Sanden repeatedly stressed that the oil was a full charge and to not replace it. I did not add extra oil except to the o-rings when putting everything together.

 

I weighed in the charge using a scale that I know to be accurate. It's entirely possible that the system is very slightly undercharged due to loss from my manifold gauges and purging them, but if so it can't be much.

[grumpiebill]

Rock On, I would question weather or not SP15 is compatible with R134a. I have always used PAG. I have always presumed Sanden to noisy anyway and have never had one that didn't leak where the front face fastens to main body...

The compressor came with a full charge of SP-15 oil which as far as I can tell is equivalent to PAG 100. The instructions from Sanden repeatedly stressed that the oil was a full charge and to not replace it. I did not add extra oil except to the o-rings when putting everything together.
 
I weighed in the charge using a scale that I know to be accurate. It's entirely possible that the system is very slightly undercharged due to loss from my manifold gauges and purging them, but if so it can't be much.

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[Minuit]

9 minutes ago, grumpiebill said:

Rock On, I would question weather or not SP15 is compatible with R134a. I have always used PAG. I have always presumed Sanden to noisy anyway and have never had one that didn't leak where the front face fastens to main body...

 

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I think SP-15 is just Sanden's own brand of PAG oil. This is a newer compressor specifically for R-134a. As far as I can tell it's practically identical to the old R-12 compressor with different fittings on the back though.

 

If this noise is just the normal Sanden noise, that's fine with me. I have heard other A/C guys call them noisy. I just want to make sure it's not about to explode! I'm pretty sure my 1996 Thunderbird still has its original FS10, and it's pretty much completely silent, but I don't really have a baseline for normal with one of these Sandens.

 

FWIW - the old compressor leaked out of both the front seal and the seam where the back plate fastened to the main body. If you ran it long enough it would start to foul the belt with oil. It also sounded a lot like this new one (even had the same rumble inside the cab), but I always thought that was because it was old and worn out.

 

Thanks for responding! 

[gogmorgo]

I don't know that I ever had an appreciable amount of noise with my '91's a/c going. And I only ever noticed the rpm drop or any other effects from switching it on when I was at idle. 

[grumpiebill]

RPM should momentarily drop then come right back up depending on carb or EFI. Carburator should have stepper motor either single wire or maybe 2 or 3 wire depending on if it's a feedback or not. EFI uses a 3 wire idle air control motor which responds a little quicker than a stepper motor making A/C idle up barely noticeable..

I don't know that I ever had an appreciable amount of noise with my '91's a/c going. And I only ever noticed the rpm drop or any other effects from switching it on when I was at idle. 

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