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burning smell, screeching and finally knocking Pages: 12

1994grandam on Sat September 14, 2013 10:06 PM User is offline

Year: 1994
Make: Pontiac
Model: Grand Am
Engine Size: 2.3
Refrigerant Type: R134-A
Ambient Temp: 100
Pressure Low: 55psi
Pressure High: 250
Country of Origin: United States

Hello, my mom's car A/C messed up today.

We went to take her vacuum cleaners to Oreck to make sure she got the right filter and belts.

A/C was running perfect right before.

When we left, I noticed it was not cold, but waited a little while, then we drove about a mile to go get something to eat, smelled a burning smell so turned it off.

Upon parking at Fuddruckers (good burgers by the way, kinda pricey though) I turned off the car, then I wanted to try starting it again, heard what I thought was a belt slipping, turned off air noise stopped.

After eating I tried one more time to make sure the belt was ok, told her to turn on A/C the compresor did not engage, the the pully just freewheeled, and I saw what i thought was a mist of refrigerant oil on the driver's side of engine bay.

Got home and checked it out, I put my gauge on the low port, thinking maybe system went flat, gauge pegged out, so I started the car and turned on A/C, it had a little delay but kicked on, suction pressure pulled down, car was cooling, suction line coming out of firewall beer can cold!

Then I turned it off waited a few, tried again, and I thought hmm, oh well, and was gonna just see how it goes from then, then I heard a bad sound, like a light knock knock, then go away.

I was looking over the engine bay at the compressor, when I heard a loud noise and I jumped, thinking man something could let go and hit me in the face, sound went away, then came back constant.

I'm thinking it's either the compressor, or the compressor clutch bearing, and clutch.

It has a constant knock sound now, and I'm wanting to not drive with the A/C on, so with the burning smell we had (car is old and get engine bay smells in it at red lights normally, the blower housing is all brittle and broken) do you think it could be the A/C clutch, and bearing?

1994grandam on Sat September 14, 2013 10:18 PM User is offline

Oops, I meant the mist of what looked like refrigerant oil was on the passenger side.

mk378 on Sun September 15, 2013 8:19 AM User is offline

Condenser fans working?

1994grandam on Sun September 15, 2013 1:36 PM User is offline

Yes it is, just noise from the compressor, cools fine still.

Leggie on Mon September 16, 2013 10:45 AM User is offline

How many times has this car been refilled with quick DIY charge kits? If you have too much oil, it can certainly hydrolock the pistons and stall the shaft.

1994grandam on Mon September 16, 2013 4:05 PM User is offline

Once that I know of, when my mom had the car in Texas, my brother "added freon" and was all proud, it was my grandmothers car before that.

April 2012, I replaced the suction/discharge hose as it comes in one piece, due to a slice on the discharge hose, which I believe a oil change did to make $$$.

I flew to Texas to pick the car up, my brother picked me up in his truck at the airport and he told me he was sorry but the car's a/c had just gone out that day after he took it for a oil change, it was fine before bringing it in.

I bought a charge kit at wal mart just to see and heard the hiss, and saw what looked like someone sliced the metal tube near the radiator, however there was a plastic ridge near it on the fan shroud that was in line with the slice, I still suspect foul play as it worked right before the oil change, and I'm guessing they made the slice there to make it look like it had rubbed on the plastic, maybe it was something that happened on it's own, just strange the A/C suddenly gets a major leak at the oil change place.

I used my 30 Lb container of R134-A at home after the repair and evacuation, I did commercial refrigeration for a little while, and am a HVAC tech, just not a professional on cars.

1994grandam on Tue September 17, 2013 12:15 AM User is offline

I guess I will just drive it until something breaks, then replace compressor.

mk378 on Tue September 17, 2013 10:37 AM User is offline

Check the bearing by removing the belt and spin the pulley by hand, check for any noise or play in the bearing. If the compressor internals are making noise with normal system pressures, consider replacing it before it blows up completely and seriously contaminates the system with debris.

1994grandam on Tue September 17, 2013 5:36 PM User is offline

I just laid next to the car and spun the piece on the end, not pulley, belt still on, it turns pretty easy and has play in it if you spin it the other way, maybe I can feel one at a auto parts store to compare.

1994grandam on Tue September 17, 2013 7:00 PM User is offline

Does that sound right, right now this is the only transportation I have, and I live in a area where walking to the parts store is very far.

Maybe I should just get a new or rebuilt compressor Rock auto with basic shipping only saves about 4 bucks pre sales tax vs O'Reilly and autozone, lol.

1994grandam on Wed September 18, 2013 12:05 AM User is offline

I cannot get the belt off, the tensioner bolt head is slipping in my 13 mm box wrench, 12 mm too small, just for kicks tried standard, of course it's between the frame so I cannot fit a socket on it!

1994grandam on Wed September 18, 2013 3:26 AM User is offline

Well, I finally got the belt off and spun the pulley, no play that I could feel, but I hear a slight noise, then again that may be normal.

The the end part does spin when the a/c is on, however again hooking up gauges, the suction pressure only goes down a little, near sunset it was just below 80 psi, shut car off and pressure went up about 5 psi.

So, I'm going to guess something internal broke. Looks like a pain to replace this compressor.

Chick on Fri September 20, 2013 2:19 PM User is offlineView users profile

Your car uses a variable displacement compressor. (V5). You won't get correct pressures unless the system is fully charged.. A high low side makes me lean towards that, but you don't have the high side.. Most important if you change the compressor is to have it vacuumed and recharged into the vacuum using the correct weight... No shortcuts.. Do it once and do it right.. Hope this helps..
Your car uses an expansion valve system and drier..

Email: Chick


Freedoms just another word for nothing left to lose

1994grandam on Fri September 20, 2013 7:13 PM User is offline

Hey, I was reading these have a part called a compressor control valve, could that cause a problem of not pumping?

1994grandam on Fri September 20, 2013 7:22 PM User is offline

4:20 pm checked suction @ 118 and discharge @ 140 pressures, 102 F ambient, end hub is spinning.

mk378 on Fri September 20, 2013 9:04 PM User is offline

When a compressor is making noise you should replace the whole thing. Often, but not always, the problem with a V5 that spins but doesn't pump much, is the control valve. Yours is likely one of those other cases though.

Edited: Fri September 20, 2013 at 9:05 PM by mk378

1994grandam on Fri September 20, 2013 9:51 PM User is offline

Oh, I need to mention, does not make any bad noises now, sounds normal.

Chick on Sat September 21, 2013 12:11 PM User is offlineView users profile

You will not know if the compressor is shot unless you have a full charge in it.. Especially with V5's.. Any leak will cause the pressures to rise after a while.. totally different than axial compressors.. even expansion valve systems and O'tube systems are different.. If in doubt, contact
and get a price for a new compressor, and be done with it.. Hope this helps.. board sponser

Email: Chick


Freedoms just another word for nothing left to lose

Edited: Sat September 21, 2013 at 12:23 PM by Chick

1994grandam on Sun May 18, 2014 2:56 PM User is offline

Thank you Tim for helping me to get back here, I had been logging in, or so I thought make a reply, to be told "Sorry, you must be logged in to access the requested object. Error Code: 104" somehow my email popped in as my username, and I thought that was what was needed.

Anyways, I bought a brand new compressor, receiver drier, and expansion valve.

Last night I got the old compressor out, first thing back in Sept when the failure first happened, it still had good pressures, today it was flat.

It was tough getting the compressor out, I went to drain the oil into a pickle jar I had cleaned out, so I could match the amount of old oil drained, well it was bone dry, if I rattle the compressor, I can hear broken pieces in it. So, does this mean the black death?

Can I flush with R134A, I have a drum, or do I need a solvent? How much oil should I add, I bought PAG 100. I was hoping to skip doing the expansion valve, as I could not find where it is located, but guessing tear the console out of the car, pulled a panel down in passenger foot well and found the engine control module (computer).

Edited: Sun May 18, 2014 at 2:57 PM by 1994grandam

1994grandam on Sun May 18, 2014 3:02 PM User is offline

I forgot to mention, not long after my last post in September, it quit again, and seized up, of course the belt pulley still rotated, I put a small 1/4 ratchet and socket on the nut on the compressor shaft, I could not get it to budge, so the car was just driven all this time (8 months)with no A/C.

I came back then to update, but was having the log in issues then as well.

Edited: Sun May 18, 2014 at 3:04 PM by 1994grandam

1994grandam on Sun May 18, 2014 3:31 PM User is offline

So I went into the flushing part of the site, and found a website called HECAT INC, and read R134-a would just be vapor and not push any junk.

wptski on Sun May 18, 2014 11:08 PM User is offline

Originally posted by: 1994grandam
So I went into the flushing part of the site, and found a website called HECAT INC, and read R134-a would just be vapor and not push any junk.
Flushing with any refrigerant these days would be illegal.

HECAT on Mon May 19, 2014 10:45 AM User is offline

It takes a lot of back pressure to keep the typical refrigerant (working fluid) as a liquid for flushing. Just purging or venting a refrigerant in a flush process is futile, as the refrigerant will gas way too fast to work; not to mention it is illegal. Using higher boiling point HFC refrigerants in a closed loop process is done, but requires expensive equipment.

The most common DIY method is to use a solvent. It needs to be introduced with a method capable of penetrating the open chambers and parallel path micro channels of todays complex heat exchangers, or this just also becomes a futile attempt.

You may want to look at this

Select the right solvent for the job, apply it with a capable flush tooling, and make sure you have removed all the solvent. Not doing it right, and following the common paths of short-cutting, often just result in poor cleaning and further or different contamination to the system (I.e. not clean and dry).


HECAT: You support the Forum when you consider for your a/c parts.


1994grandam on Mon May 19, 2014 11:32 PM User is offline

I ended up skipping the flush, and putting it together, as I had to have the car mobile, it works, however I know it could have problems down the road.

Now, for future car or even this, I would most likely take it to a shop with the special machine that does the best, does this machine do it with the compressor on the car, or does the lines to the compressor need to be removed?

The link has a DIY kit, but for the price I would just go ahead and pay a special shop to do it, as it would be a 1 time thing.

Is there a place in the Phoenix area that uses this best HECAT flushing machine?

Edited: Mon May 19, 2014 at 11:36 PM by 1994grandam

1994grandam on Mon May 19, 2014 11:40 PM User is offline

Also, does the flush remove the refrigerant oil from the system?

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