Jump to content

AC Issues....


ptt

Recommended Posts

1990 coupe w/127K miles. Hooked gauges up after ac started blowing warm air. Car has sat overnight so before starting the gauges showed 150psi both lowside and highside. Started engine and the pressure didnt change. Wouldnt take any refridgerant at the low pressure sevice port. Disconnected positive battry cable for a few minutes but didnt help anything. Any thoughts appreciated. Thanks.

Link to comment
Share on other sites

Guest Richard D

Just to be safe now that you know there is equal pressure on both sides don't let the low side get hooked to a can of refrigerant until you get compressor running. That said I have never heard of a can coming apart at 150 psi. but saw the remains of one that blew it's safety vent at 185 psi. Was not pretty.

Link to comment
Share on other sites

Mc Reatta is correct! Fuse #19 was blown. I dont have any idea why the fuse went but it is the second time it has gone in this particular Reatta. Happened last Summer also. Would making sure the AC is turned OFF when turning the engine off so it is not ON upon starting the car assure that the AC circuit isnt hit with an electrical surge??? Thoughts appreciated!

Link to comment
Share on other sites

Guest Mc_Reatta

Most likely culprit is the clutch coil. If the BCM, AC relay, pressure switch or wiring in this circuit were bad I would expect fuse would not last anytime at all. Sounds like you will need a new compressor or at least a new clutch sometime in the future if the fuse keeps blowing out.

Link to comment
Share on other sites

ptt, I had a similar problem on a '91 Cadillac. It had a fairly fresh GM compressor. I had to hook up an inline Fluke dc ampmeter at the fuse holder port and check the amperage at fuse, it had excessive current draw and low resistance on clutch circuit. You can also check resistance at the clutch by removing the connector. If I recall correctly it had a resistance of less than .5 ohm and should have been around 8-12 ohm. I had to replace the coil behind the clutch pulley, problem solved. If you have a schematic, see what else if anything is driven off that fuse 19 but check the compressor clutch resistance first and find the spec for it, it may be around 4 or 5 ohm, I don't recall. TexasJohn

Link to comment
Share on other sites

Be aware that you need a specual tool to push the puley back on to the correct gap (.020-.040 AFAIR). Just pulling down with the nut may not seat properly
The GM compressors which I have dealt with had selective shims behind the pulley on the shaft which set the clearance gap and still allowed the nut to be tightened. If the gap is reasonabley correct and the same pulley is used back, you should not have to worry about spacing. The shims are tiny and easily lost if they stick to the pulley when removed, just be aware that it may have one or more shims. John
Link to comment
Share on other sites

Guest Mc_Reatta

I'd think a while about replacing the clutch coil and bearing on an older compressor. It's a real PITA compared to just replacing the bearing. Special pullers and holders are needed and it's probably just not worth the expense and effort for a compressor whose seals are in question as well.

You can get a new compressor for not much more than the clutch bearing and coil and not have to do all that work and then have the seals start leaking a little way down the road.

Also doubt the reasonableness of doing this while the compressor is still charged and in the car due to space issues, and if you have to depressurize the system and pull the compressor out to work on it, you might as well just do the job right.

Link to comment
Share on other sites

3 years ago I had a clutch issue. My machinist friend made a puller to swap it out. We went to Gibson's [where else] walked around looking for a nice looking one, found one and pulled it [after practicing on a "ugly looking one"] took it home and installed it while the compressor was on the car. "Jumped" the compressor to make sure it worked, it did. Fast forward 3 summers and still haven't charged the system.

Why? Because it is my "winter" Reatta and comes out in October and back to bed in April. Not much need for A/C in Wisconsin for those months.

I always think about charging it but never get that "roundtoit" you guys keep talking about...

Link to comment
Share on other sites

Something tells me you can replace the clutch hub, pulley, and coil without discharging the Freon. Is this right? Been awhile, but I think that's the case. I now just replace the whole compressor with new; they're cheap enough...

That is true and that is what we did...

Link to comment
Share on other sites

Guest Mc_Reatta

It's easy enough to pull the pulley and bearing off with the compressor still hooked up and in the car. Just go to your FLAPS and borrow the correct puller tool and seating tool. Getting the coil out (the part that is probably the problem blowing the fuse here) is much more involved. If you RTFM on how it's done (page 06-ID2-8 in 89 FSM), they show holding the compressor body in a vice and use a special puller and plate (not the same as used to remove the pulley). There's no way that could be done in the car. and I doubt there is room enough to devise a method to do it in situ.

Just get a new compressor, orifice tube and receiver/drier and do it up right if the fuse keeps blowing, and the clutch coil shows the low resistance as mentioned earlier.

Believe me, BTDT. And if it was any way worthwhile doing, I would have done it.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...