a/c issues 1998 Tahoe...

[1998 NY]

The a/c system in my Tahoe has had a small leak somewhere and I loose all freon sometime over the winter; all gone by the time summer starts and time to use a/c.

I took it in to get charged as usual, some dye, etc...they said they found the leak. Replaced the dryer and a valve on engine top.

Day later the rear a/c was blowing cold, but front was ambient temp only. Took it back to mechanic. They said: could be this, could be that....but really I feel they they had no clue.

Today no cold air anywhere, and worse very bad sound coming from compressor. Sounded and smelled like belt was slipping, burning a bit.

I know the a/c system is complex and can involve a bit of forensics, but can someone suggest a path of least resistance and cost for labor? I will not attempt myself, but hoping to get an idea of what could be done first before I hand it over to someone at $100++ per hour labor (worse here in NYC).

Eg, Can I get an inexpensive check up done on the system at say a Jiffy Lube or similar?

Is there some affordable and reliable option in order to get a diagnosis?

Thx in advance
Randy

Also, let me add, for what its worth, the above mechanic did find a coolant leak so replaced intake manifold gasket and water pump (I inspected both and was justified). Just wondering if anything could have fooled w the a/c system.

 

[lesterl]

Need to check both high side and low side service ports, I have had issues with leaks there, as well as other rubber seals/ gaskets in the system.....

 

[hshark]

ok these vehicles tend to leak from the compressor. Check your hoses and make sure you have no cracks etc. To do a test yourself get a sprayer with soapy water and turn the key on with the a/c on dont have the vehcile running just turn the key. spray the soapy solution near the compressor where it seems that it joins together. If you get bubles you have found your leak. If no bubles move on to the hoses etc. Remeber anywhere you get bubble formation you have a leak.

 

[1998 NY]

Thanks for this...

Compressor is seizing as of two days ago...so looks like I have a larger job on my hands.

Cant tell whether the repair shop should have seen this coming before they suggested and replaced the receiver/drier.

 

[lesterl]

I picked up a good compressor for my minivan off Ebay for $50 shipped/guaranteed 30 days, I installed it 2 years ago, been working ever since.... Compressors arent hard to replace.

 

[hshark]

I suggest buying a new compressor,dryer and making sure your sytem is completely cleaned out. If any debris gets into your new compressor you will have to replace it again. make sure you take it to a quality shop that will do things correctly. it is not just putting freon in the system it needs to be cleaned out using proper tecniques. Also make sure you use new O-rings.

 

[1998 NY]

Yes. I meant a larger job than I can handle. Quality shop is the question.

Is there standard procedure to this cleaning of the system? And anything else that needs to be replaced? Hoping I can be somewhat armed when I speak with the mechanic. I could see someone easily tacking on labor and parts if I dont know. (forgive the pessimism here, just my experience...a couple of times here in the greater New York City area)

Thx for your time. Hope im not bothering by asking too much.

Kind regards

 

[hshark]

I dont know exactly what the termonology is, but the entire system needs to be flushed out moisture needs to be removed from the entire system as any debris or metal from the damaged compressor if any need to be removed from the system. The hoses need to be cleaned out with proper a/c cleaning solution and blown out with a filtered and good quality air source. New valves need to be put in. This is the basic procedure for a contaminated system. Now if your system is not contaminated with metal shavings due to compressor failure. You need at the minimum removal of system moisture and a pressure test to find leaks if any after compressor install. Remember it is not only about a re-charge the system needs to be flushed and tested with proper guages etc.

 

[hshark]

and what makes you say the compressor is seizing? is it not engaing? making noise? what is it doing for you to say this? Remember if you have a leak and from what i gather you do, not having any or extrememly low freon levels will not allow the compressor to engage.

 

[hshark]

i have attached a video so you may better understand what is proper servicing for a contaminated system due to compressor failure etc.

http://www.youtube.com/watch?v=TeqhOqK1TNA

 

[1998 NY]

Heard skreaching sound in engine first, then burning smell. Looked under hood and compressor was glowing inside its casing. Def shot.

Seems pretty clear need full vacuum of system and replace all parts you mentioned.

 

[1998 NY]

Just ckd the link. Perfect. Excellent! Thank you.

 

[1998 NY]

So my saga continues.

New compressor, syastem has been evacuated. But I have a leak. There was some cold air coming out rear for a small while. Now no cold air front or back. The freon is being lost.

Dye has been placed in the last charge. I had a second mechanic do a black light test today (for insurance). He said there is no leak in any lines under the hood. The problem must lie in the cabin.

I was told I have to look at both evaporators in front and rear. The labor for this, if I pay for it, is substantial. Im hoping to open it all up myself, then black light it again.

Does anyone know where I can find a breakdown of taking the dash apart to get at evap?

Also, there is a rear evap correct? And anywhere I can find a breakdown of getting at this too?

thx in advance.

 

[lesterl]

https://www.youtube.com/watch?v=UW1GDiOa0kE

I use a visible dye, it is bright red in color, I get it at WalMart for about $5 for a can. BTW they have R134a for $9.xx a can also...... Charge it with the dye and start looking at seals, look at valve cores, look condenser and both front and back evaps over good. I have had a bad time with valve cores leaking here lately....

 

[1998 NY]

Lester,

Thx so much for the reply. What I'm really wondering is just how to take apart the dash to get at the evaporator. If there is a diagram or directions w pictures somewhere?

And the same for taking apart the rear....

 

[lesterl]

Dash is not fun..... and I think you found a good link for the front, the rear I am not shure, the only rear air I have is on my minivan and I have never had it apart...... sorry....

http://www.tahoeforum.com/showthread.php?p=628918#post628918

 

[1998 NY]

Thx Lester. Even w that link for the front Im struggling to make out some of the diagrams. (eg #7-PSIR bracket ??) But Ill keep trolling web. Hopefully there's something for the uninitiated.

Ive gotten to dropping steering column and Im stuck.

 

[lesterl]

PSIR is Passenger Supplimental Inflatable Restraint (passenger Air bag...) There is a cross brace that helps stiffen the dash on that side.