Hi all,
my 92 saturn only blows cold air while driving....but warms up while at a light or in traffic. def over 100K miles (odometer stopped working). Mechanic replaced compressor, exp valve, suction hose, receiver dryer, added freon and checked for leaks with dye ($1,186 total) but he can't seem to explain why i'm having this problem. This car is my baby but the Florida heat is killing me and I'd hate to choose between the two.
Any ideas?

Thanks in advance.
Cadman33619

 

The radiator fan is not working. Proof --> start engine, and set A/C to maximum cooling and the air control to recirculate. Now, open the hood, and look at the electric fan on the radiator - it should be running. If not, you are going to have to troubleshoot and figure out why. (Hint - start with the fuse)

 

Thanks for the reply, OceanArcher....
We've confirmed that the fan is working properly (sorry, should have mentioned that). It turns on when the a/c is on...and when the a/c is not running the fan turns on when its supposed to and cools the engine just like clockwork. I thought maybe the fan motor is just not strong enough and not pushing enough air....could that be it?

cadman33619

 

As long as the engine is not overheating in traffic, or while idling when stopped, I suspect that the fan is supplying sufficinet air to keep thing cool. That said, it remains that your vehicle A/C system runs cool when on the open road, but doesn't work properly when stopped. From your comments, it looks like your mechanic has replaced almost every part of the system with the exception of the expansion coil inside the car, and the cooling condensor outside.

Let's do a test - park your car outside and start it up. Drive around a little bit, so the A/C starts acting up (low/no cooling). Stop the car, open the hood. Now, gently increase the speed of the engine (still stopped) at about 2400rpm. That's about the same as driving down the road. Hold it there for a while, and see if the A/C goes back to proper cooling.

Second test - with the car parked, the engine running (at idle speed), and the hood open, use a leaf blower (or other device) to direct high velocity air through the cooling condensor. Again, check for good cooling results inside the car.

What I'm trying to do, is to discover which causes the system to go back to cooling ...
more air through the system, or more speed on the compressor. I know, you already had the compressor replaced, but I'm thinking of a possibly partially obstructed coil - either internally or externally .....

 

I see what you mean, Ocean....
makes a lot of sense. I'll get started on both test asap and let you know the results.
If the condensor is partially blocked...is it possible for me to take care of that?..i'm pretty good at working on this car. I've done many repairs with the help of the repair manual. As for the coil...where is that located, exactly?

Thanks
Cadman33619

 

OK both test complete....
test 1:
ran the car a little to reproduce the problem. parked and kept my foot on the accelerator (up to 2400 rpm) for a while. the air got cold immediately. (really cold). Did this s few times with the same results.

Test 2:
used a blower on hi to blow air into the front end. The air did get colder but not as cold as test 1. Did this a few times with the same results.

what do you think?
Cadman33619

 

Sounds like an internal blockage/restriction in the condensor core. NOTE, THIS IS NOT A NORMAL TYPE OF FAILURE, and could possibly be a blockage/restriction in one of the hoses/lines (although you mentioned your mechanic has already replaced the hoses). The reason why the system operates when you increase the RPMs is because the higher speed of the compressor pushes a larger volume per unit of time, (pressure will be up too), pushing enough cooling past the restriction to allow the A/C to operate.

My suggestion would be to have your A/C man break into the system again, and locate the blockage.

 

I'll have him look at it again and let you know what he finds.
Thanks for all your help, Ocean

cadman33619

 

Add A/C expertise to OA's tranny wisdom (that we know about)

(the list grows as OA shares what is obviously a breadth of automotive knowledge)