A/C clutch burned 3 times!

[Gijs]

Hello i have a strange problem with my ac. About 3 month ago it stopped working and it went out with much noise smoke an a very bad smell.
The dealer found out it was the clutch, not the compressor. So they installed a new clutch and everything seemed fine. But when i went to the dealer to pick up my car it went wrong again with sparks and smoke. Next day they took it apart again and installed a new clutch and after inspection by an specialist it seemed that the bearing from the compressor was gone bad so a complete new compressor was installed too, just to be sure. It took fot about 2,5 months and the problem is the same, much noise, smoke and a terrible smell. Today the dealer took it apart again and the clutch was completely gone. The compressor seemed to be fine and when you turn it by hand it feels very smooth??? This is a long story, i know, but now i am stuck, the dealer does not know what to do so now my hope is that one of you has experianced this before.....anybody with an answer???

 

[Briank]

Sounds like you are getting some kind of liquid in the compressor which will not compress and it locks up the compressor and burns up the clutch. The liquids could be Freon or oil. It could also be a bad triple pressure switch which is not turning off the compressor when the pressure gets to high.

 

[Gijs]

Thank you Briank, how do i test these things and how can freon or oil not get compressed. I always thought that was just what was in the system. Mayeby you mean that is is not mixed together?

 

[Briank]

Normally the oil is mixed with the Freon but they can separate under the right conditions as can the Freon be a liquid at the right pressure and temp. If the system is overcharged with Freon liquid Freon can be present and get sucked into the compressor. Normally in an overcharged system the pressure switch will just shut down the compressor but that is why I think you may have a pressure switch issue.

I would check the connections to the pressure switch and its operation and then evac and recharge with the proper measuerd amount of freon.

 

[Gijs]

Hello, the pressure was ok after filling the system and let it run for a long time but the pressure switch is never checkt. We will check this at first. An other thing the mechanic said was that it could be an electrical problem. He now thinks that the clutch does not get enough power due to bad electrics....is this possible?

 

[DutchBlackNsx]

Heyyyyy...

I had one of me compressors go like that as well.
At the time i had a leaking AC system, which i blamed it on.

 

[Gijs]

Briank, hello again i have one more qeustion. Where is the pressure switch and how can we test it?

 

[Briank]

Here is the presure switch.

http://www.nsxprime.com/forums/attachment.php?attachmentid=17722&d=1121202041

See http://www.nsxprime.com/wiki/Service_manuals for the service manual see sec 22 page 59

 

[goldNSX]

Heyyyyy...

I had one of me compressors go like that as well.
At the time i had a leaking AC system, which i blamed it on.

If you loose Freon the system is shot down by a switch unless this switch is gone bad. This has happened to me several times and nothing went bad.

It works in my car because it's good sign if I'm low on freon.

 

[Gijs]

Thankx Briank for your answer tomorrow we will look in to ie and let you know.

 

[Larry Bastanza]

I would carefully check your idler pulley and crank pulley. This really sounds like a mechanical/vibration failure, since the compressor itself turns smoothly.

Just a thought.

HTH,
LarryB

 

[Gijs]

Hello Larry, thank you for looking into my problem. Silly question: where is the idler pully and where is the cranck pully and how do i check these, and is it difficult/expensive to change them if nessasery?
Second question: this morning i talked to the mechanic and he still thinks it is an electrical problem. He says the clutch does not get enough power so it does not fully engage. Is this possible?

 

[goldNSX]

Second question: this morning i talked to the mechanic and he still thinks it is an electrical problem. He says the clutch does not get enough power so it does not fully engage. Is this possible?

If the stator set (clutch switch is faulty) then maybe yes.

 

[Briank]

The compressor clutch is turned on by a relay a very simple system. I guess the relay could be bad but its very unlikelly. Install a new one and see if the clutch burns up again.

 

[Gijs]

Well Briank, that is a bit of a problem because a new clutch costs over 550 euro without laber. All the information you and others have given me is told to my dealer and now it is up to him what to do. And me? I am going for a testdrive in a new type r civic this weekend............a red one.

 

[goldNSX]

Well Briank, that is a bit of a problem because a new clutch costs over 550 euro without laber. All the information you and others have given me is told to my dealer and now it is up to him what to do. And me? I am going for a testdrive in a new type r civic this weekend............a red one.

You let your dealer burn up three clutch sets and still leave it up to him? Maybe he's not the right one to solve problem. :wink:

 

[Gijs]

That's the problem i don't know where else to go. And i already payed the dealer big bugs and it hold for only 3 month so it is not my plan to pay him any more. But as i said this weekend i am going fot a test drive in a new car and mayeby all my problems are solved next week.

 

[DutchBlackNsx]

Gijs,

Give us a pm where you located, i know a shop who understand AC systems.
Been there done it with the dealers and such.

Mich


oh, and btw, the FN2 (CTR) is a great car, but NOT a NSX replacement (got one on order myself though).

 

[ralph cerbone]

just hold on , i read your post a few days a go but i have been busy so i apoligize for not posting sooner , i have seen this problem a few times ,it is not mechanical , based on what your saying i would suspect you have a bad ground on your compressor (voltage drop ) all a/c comp. have a high pressure relief valve , the eletro magnetic clutch is more than capable to take these units into pressure relief ( > 400 psi) i have seen where a bad ground will allow the comp. to engage but as press. builds the clutch will slip ,in my a/c class i show students the effect of adding liquid freon to an a/c system while it is running , the comp. sometimes will knock like detonation or even lock up and stall the car but the clutch will HOLD , you have to make sure the tech perfoms a voltage drop on the comp, this is a very basic test and will reveal if there is any loss of voltage to the clutch.

 

[Gijs]

Thank you for the responce, the dealer already measured ground by metering one and on the compressor and the other on the car body and it reads 0.
He was dooing this with the engine off. Is there a better way too measure this and could it also be a bad positive current due to a bad relais or so?

 

[drew]

Ralph brings up some good experience. I assumed a clutch would slip rather than blow the pressure relief valve....

If he is correct you have to know that current and voltage are related, but very different. A system can "check out" at low voltages (test meter), but fail miserably under high current (field conditions).

Yes, you could have poor current delivery or grounding issues. It could be a poor relay or a poor connection anywhere along the line. There should (I don't know for certain) be other relays in the car that can be swapped out to determine fault.

The real problem is, I think, is that it is difficult to test for this situation until you actually burn out another clutch. I'm not sure if it best to test the amps or the resistance across the clutch (Brian?) during operation and failure testing.

I would do the following:
1. clean and re-establish all engine grounds. Torque to spec!
2. do the same with the compressor, clean all bolt mount points.
3. if you are inclined, run a separate ground from the compressor to the, oh, the starter ground.
4. Check the connectors for corrosion and maybe lube with dielectric grease.
5. Swap, replace or bypass relays


The clutch is from a Legend. Here in the States they nearly give away parts for the Legend. In fact, the Legend compressor has slightly higher capacity 1.7 vs 1.5 so you get better throughput as a bonus.

 

[ralph cerbone]

o.k. lets start at beginning , the tech must do the volt. drop while the comp. is engerized, he will test with a volt. meter from the grnd. term. of the comp. to the neg. batt. or eng. grd ,he is allowed .2 of a volt drop (max,idealy o)
then he will test from the 12 volt supply at the comp. to main batt. (again .2 max ) the volt drop test is a fundamental electrical test , it shows any resistance in the circuit while it is turned on (ohm meters are useless because the component must be tested out of the circuit ) look with out seeing your car it is very difficult for me to diagnois , but i will tell you there is not any comp. clutch made today that cannot drive the comp. to exceed the high pressure relief setting, if you are burning comp. clutchs it is either faulty installation or insufficient current to hold it engaged , just food for thought

 

[Briank]

Fully engaged the clutch will not slip even with a locked compressor the belt will burn up. In your case the clutch is either trying to engage to a locked compressor or it is weak and trying to turn a normal compressor. Moinioring the voltage may tell you somthing but it would be better to monitor the current to see if it is consistent.

 

[Gijs]

it looks like i have a lot of work to do, first i have to wait for a new clutch and then the compressor must get checket and mayeby replaced. Then we are going to measure wich me luck. when i know more i will let you know.

 

[ralph cerbone]

Brian from reading your posts you obviously understand electricity ,i'am not talking about just putting a voltmeter on a comp. term. he can measure all the current but his problem is not blowing fuses (such as a shorted comp. coil ), if he has a voltage drop above .3 v in the power or ground side of that component he will see current go down and possibly the mag. field get weak enough to slip the clutch as the car starts to get hot and pressures rise in the a/c system ,thats where i was going , my understanding is that the system failed was repaired and failed again same sympton , theres nothing wrong with putting an amp meter in the fuse holder but if the current is down causing the clutch to slip then there has to be unwanted resistance in the circuit which performing a voltage drop test on the circuit will show you where it is .