I recently replaced my A/C system. I started a thread about the trouble I had earlier.

My first new R4 compressor failed within one week. I had a new condenser, accumulator, Soft A/C lines and orifice tube.

I believe this one failed mainly due to my manifold gauges not working correctly and not getting a good vacuum/not fully charging the system. (working with r134a, previous owners converted a long time ago and I blew the evap out with air)


Once that compressor failed, I again replaced the condenser, accumulator, orifice tube, and obviously the compressor (both AC delco new compressors.)

This time I had proper working manifold gauges, I flushed the lines and evap thoroughly with AC flush, and vacuumed the system down and let the system hold vacuum for the whole next day. I put roughly 40oz of r134a in also, trying to account for losses between swapping cans (possibly very slightly overcharged) Also, the compressor was prefilled with 6oz of oil, and I put 2oz in the accumulator, all PAG 100 oil.



My system currently is working well, and in the AZ heat so far (only low 90s), it is good with me.



HOWEVER, the compressor is NOISY! The compressor also gets decently hot if the clutch is turning for a while, and it is a noticeable parasitic load when driving. I've read that these compressor are noisy, but they are also unreliable. Based on my first one failing so easily, the noisiness of this one is worrying me.

I saw this thread: https://www.thirdgen.org/forums/cool...e-systems.html and wanted to get people's opinion on swapping out the R4 compressor.

-----------------------Here are some questions I have----------------------------

Should I be worried about the new R4 compressor being noisy (especially under throttle) even if it is cooling properly? Also, how hot to the touch do they normally get when working hard?

If I get a Sanden compressor, will I have to purchase anything else (besides the brackets and a new accumulator since the system will be opened) to make it work with my existing system?

Does the new Sanden compressor prevent the valve covers from being taken off without unbolting the compressor brackets?




When I first dealt with AC, I know I made decently large mistakes, but the compressors handled the mistakes for a while (I didn't pre oil my 96 Bronco's first compressor and it lasted over a year, also I didn't vacuum down the system the second time and didn't use a manifold gauge to fill the system and the second compressor has lasted over 2 years). I am quite shocked how delicate these R4 compressor seem to be from what I've read and experience I've had. Any advice and insight would be greatly appreciated!

 

IF the compressor is getting hot, it doesn't have enough oil in it.

As for the sanden compressor, there is a thread here that details everything that is needed since there is no direct swap sanden; it requires a custom bracket to line everything up that you'll have to make or have made.

R4 to Sanden

---edit---

I just re-read your thread and saw you already saw the thread in the link I just posted. I'm doing this Sanden swap as soon as I can afford a compressor, probably next summer since my compressor is chirping like a bird right now. But, the OP on that seems to like it very much.

 

I'm pretty sure I'll do the Sanden swap this summer. I wish I looked it up before getting two different R4 compressor.

I have to check and see how hot the compressor gets in my Bronco. It just seems like this compressor is getting too hot and makes noises I don't like hearing when I rev... I did add an oil charge can today, it was 1 oz of oil, 1 oz of r134a and 1 oz of ICE32 crap or whatever that is.

Hopefully this compressor holds out until I get the Sanden one.

 

I did this conversion 2 years ago, and my system is still going strong, I highly recommend this conversion. Depending on the conditions where you are if your compressor is pretty much running all of the time then it will get hot. The R4 will run hotter and noisier because it was designed for use with R12 which has lower head pressures, R134 runs higher pressures making the pump louder and hotter then normal.

As far as additional items for the conversion, there isn't anything else you will need, just bypass the high pressure cutout switch connector and your set. I have stock valve covers on my engine and from what I can see there doesn't seem to be any issues in regards to access. The biggest thing with this conversion is spacing the compressor in the bracket for pulley alignment. I used flat washers to finish the final alignment so the pulley's lined up properly. I aligned my pump so that the belt runs in the center of the pulley leaving one groove on each side of the belt. This conversion seems a lot more difficult then it really is.

 

what type of noise are you getting. Sometimes a groaning noise is due to a loose bolt or broken bracket somewhere. Actually a vibration causing the noise I guess.

40 oz of R134 seems a bit much too, been a while but it seems like about 30oz was pretty close with my 88.

 

The noise sometimes is a groaning type. It doesn't always "groan", but it has a higher chance to do it when I rev the engine. I can sometimes see the "slack" side of the belt flap when I hear this noise. (I have the smog pump removed so there is a large gap from where the belt goes around the AC compressor and goes to the crank pulley or whatever the next pulley is.)

I will try to check around for loose bolts. The AC brackets should be all good because I've checked them a few times (when installing my headers and also installing the AC compressor) and they've seemed ok. I'll keep an eye out on them though.

As for the 40oz, I remember reading an article I believe was on thirdgen that compared r12 to r134a and the recommended amount with converting was 40oz of r134a. I could be wrong on that though, but the cooling is pretty good and I feel it's worse to have less coolant in the system than more.

 

If you don't have the smog pump delete pully, then you need to get the shorter belt. If you don't, you can mess things up.

 

R4 compressors are always noisy. The case should get hot to the touch, but not too hot, that would be an indicator that it it's getting enough oil. Rule of thumb is that center of case should not exceed 150* F.


The belt re-route TSB helps some. Also, I'm not much a believer is snake oil, but I added an ounce of ICE32 to a very noisy R4 and it quieted down significantly.

 

Hmm okay. I did get the shorter belt with the smog delete. I forgot the exact part number but it I saw it listed on a thread here somewhere when referencing the smog pump delete (I better remember that number when I need to get a new belt.)

As for the ICE32 stuff, I also am quite weary of adding things like that especially in the AC system, but I did just recently add an oil charge kit that had 1oz of ICE32, 1 oz of oil, and 1oz of r134a. I didn't add the whole bottle, maybe half. I haven't really driven much since I added it so I don't know how well it may have worked to quite things down. My old plug wires kept getting burnt up by my headers and I had to wait to get my new pair from Summit which I'll have a chance to install tomorrow! If my compressor isn't getting enough oil, I don't quite know why it wouldn't then. I did add 8oz to the system overall, and it may have about 8.5 now with the charge kit.

I also picked up a dual radiator fan setup from a TPI camaro, so I'm going to wire in a new controller for the second fan and maybe that will help keep the compressor slightly cooler (because my temps in city driving sometimes reach about 235 and I have a 180 degree thermostat installed.) The compressor does get pretty hot, but I don't quite know how hot. I don't think it would quite yet burn my hand if I held it on there, so maybe it is around 150 degrees. My previous compressor got hot enough to burn my hand if I held it down that's for sure.

 

as was mention R134 operates at much higher pressures so you never want too much refrigerant. you install slightly less to keep the pressures down. just a few oZ over and it will be 400PSI what will happen is the hoses will blow.

on the oil . when installing a new compressor you dump out the oil. then you add new oil. I would use PAG150 not 100...

flushing the ac system and replacing the filter dryer/ orifice tube is a must on any compressor failure . this takes time as you must flush until all the gray metal is gone or the new compressor will fail. the ac system should have installed on a cleaned flushed system 8-9OZ of oil.. too little oil the compressor will fail and the seals will leak oil also lubes these compressor seals.

when installing the new seals on the connections you put ac refrigerant mineral oil NOT PAG OIL on the seals.. this will keep these from deteriorating.. pumping the system down for a few hours is good to boil off all the moisture see if it hold vacuum.. then put a 12 oz in then check for leaks with the dye checker...good luck .

 

Jcat, just curious, what kind of experience do you have with AC systems? Seems like you have quite a bit. )

 

I have license also worked transportation vehicles for almost 3 decades.

conversion to R134 with a R12 system is not going to work as well as the R12.

R134 system has more coils ,closer spacer fins to get that pressure down absorb the heat and release the heat .

I purchased R12 30years ago for $8 a 12 OZ can. still have plenty for my 84 Berlinetta..
many do have short life with these conversions , too much refrigerant . what this does is you get what they call slugging . this is when liquid refrigerant gets into the compressor then the valves get damaged and the compressor can no longer create any pressure valves bent.

I used to get people complaining the vehicle HVAC was too cold..

well with the proper pressures and a clean evap and condenser this is why.

Our vehicles are much less complicated than these big vehicles I worked. It is all about the proper amount of refrigerant and no air in the system...also leak control..

 

I had my AC converted 10 years ago now to R134 but it's never run "Cold" unless I'm on the freeway. But if I'm doing that, I've most likely got my T-tops off. I just want it to be cold around town again.

 

that is what happens , it works OK when your on the hywy. less heat load since the vehicle is moving and more flow thru the condenser.

when in traffic not all that effective R134 in a R12 system.

 

Hmm I never read about covering the o-rings in mineral oil.... I used the PAG 100. I did that with my Bronco also (PAG46 on that one) with the seals so hopefully they last a while still... Someone else recommended to me that the PAG 100 oil was a little better suited for these camaros than the PAG 150 so that's why I used it. I don't know much the differences in the oil in these systems so I'm a little clueless on that aspect.

I thought that even a little bit of mineral oil (like if it accidentally got in the lines when covering the o-rings) would be very bad for the system with PAG oil. I suppose it's probably such a small amount with the o-rings though it wouldn't really make a difference. I'll definitely keep that in mind the next time I fill an AC system.

So far my AC is still holding up well and cooling great. I know R12 would be better, but the Camaro cools better than my 96 Bronco so that's nice. Its probably mainly because there is much less space to cool in the Camaro though.

 

the mineral oil on the O rings is to keep these rubber parts from breaking down. keeps the rubber better when EXPOSED to air... that is the problem with PAG,,,.

check your high side pressure. connect up the gauge manifold before starting. should be below 380 PSI @90 deg f..

noise could be slugging which is from too much refrigerant.
too little oil as well makes the compressor noisy..too hot can be from too high pressures. also make sure the low pressure switch works properly ... below 10psi or so the compressor should drop out.

having a restriction can create low suction pressures.

like you say the compressor failed , but I did not see you say you used ac flush on the condenser. the condenser is where most of the metal debris goes when the compressor fails. in adidtion to flush you can wash out the condenser then blow out the water until clear.. in AZ this should dry out fast..

 

I'll recheck my low and high pressure when it gets a little hotter out. We've had some pretty different weather here where it gets hot, then it rains and cools down. Today it seems very nice outside so I might not have to use the AC. I did adjust my low pressure switch on the accumulator too because I believe it wasn't adjusted properly from when the previous owners had the system converted to r134a, but I'll recheck that too.


As for flushing, I flushed the evap and lines when my first new compressor failed, but I completely replaced the condenser again, so the condenser, accumulator and compressor are all brand new.

 

so even if the condenser is new I would blow it out just to be sure its clean esp.. if the tubes are not sealed. if the low pressure switch allows the compressor to run below 10PSI it will get noisy.

possible that the compressor is just noisy. the one I had replaced 2 yrs ago has a vibration .. OEM never did that , never knew it was on.

as you know when you purchase a new compressor the warranty states that the complete system need be flushed. also replacing the filter dryer.

when I worked the large transportation vehicles the filter dryer and oil was changed whenever we opened up the system.. also changing the oil was done if it was too dark.. it can happen when working the units the oil gets contaminated. these had a sight glass to observe oil level and condition...