2002 Pontiac Ram Air Trans Am ac is not cooling properly

[dannyual320]

B52, I just did some internet searching to see if I could find a wattage rating for the fans and I came up with nothing. I can look at the fan motors later in the week when I take things apart. Maybe I'll get lucky and there will be something useful on the fan's sticker.

[bohica2xo]

That is an ongoing problem with electric fans. No real metrics for the OEM motors, and aftermarket stuff is all over the place.

Usually the difference between ram air & parked cooling is a good indicator. Duct taping the gauge set on the windshield on the passenger side & going for a drive with an observer. Yeah, it sounds crazy, but sometimes you need pressure readings above 50 mph to get solid data.

Fans, whether electric or mechanical, unload at speed. Contrary to internet lore they do not offer a restriction at highway speed. The fans are there for idle to low speed operation.

One of the reasons we ask for a full load test - Doors open, cabin fan on highest speed, engine RPM above 1500. This duplicates a hot drive off from a parking lot after heat soak - like leaving work. This tests the condenser fan airflow, as well as the compressor output at full capacity.

When you inspect the heat exchangers, look at everything. Adding a bit of foam weather stripping to the edge gaps on GM trucks is a common fix to make sure 100% of the airflow goes through, not around.

Manufacturers got more serious about those problems as time goes on. Eventually we will see brushless fan motors with rpm feedback.

[dannyual320]

This afternoon I finally got around to disassembling the entire Ram Air filter assembly that covers the top of the radiator and condenser. Once it was all apart it was apparent that there was little to no restriction. There was one cellophane cigarette package wrapper caught at the top of the radiator and there is a small amount of debris in the front of the radiator. The backside of the condenser is clean like the front side.

Here are some pictures:

This is the debris on the front of the radiator
https://www.amazon.com/photos/shared/lG ... voc5XAwy2g

Cigarette wrapper!
https://www.amazon.com/photos/shared/c7 ... oncM6igFyW

Clean backside of the condenser. This is looking toward the front of the car.
https://www.amazon.com/photos/shared/CB ... a2Wz_PKTWI

All the OEM pieces looked to be in place with nothing missing. If I've got an airflow problem, I don't think it's from any blockage of airflow or airflow bypassing the condenser. It's still to be determined whether or not the fans are pulling air at 100% capacity.

[dannyual320]

BTW, I did go overboard and buy the bigger Mastercool 69100 recovery machine kit. Tracking information says that it should be here on the 15th of the month.

Once I have time to use it I'll recover the refrigerant in the system, weigh it and let everyone know how much is in there.

[dannyual320]

Stuff can still lodge inside the fins and block airflow even though they appear clean. You want to see light shining through them.

I didn't think about that. Other than the slight amount of debris in one of the pictures that I linked in my last post, the fins all looked sparkly clean. I can try using a flashlight to confirm.

[bohica2xo]

Ask yourself, how did the debris get all the way to the radiator? Through the condenser? Or around it somehow?

And A19 has a valid point. I have seen condensers clogged with gnats, while the surface is clean. I always recommend deep cleaning the fins with a strong surfactant like simple green, sprayed in to the fins on a cold condenser. Let it soak for a few minutes, then flush it with a garden hose. You may be surprised at what comes out.

Use a drop light in the engine bay at night. Get down level with the heat exchangers and look at the light coming through.

[dannyual320]

Stuff can still lodge inside the fins and block airflow even though they appear clean. You want to see light shining through them.

Ask yourself, how did the debris get all the way to the radiator? Through the condenser? Or around it somehow?

And A19 has a valid point. I have seen condensers clogged with gnats, while the surface is clean. I always recommend deep cleaning the fins with a strong surfactant like simple green, sprayed in to the fins on a cold condenser. Let it soak for a few minutes, then flush it with a garden hose. You may be surprised at what comes out.

Use a drop light in the engine bay at night. Get down level with the heat exchangers and look at the light coming through.

So I spent some time over the weekend looking closer at my condenser and radiator. I took air dams/deflectors apart so I could get closer and better looks at the condenser and radiator. There is only so much that I can move the condenser while it's still hooked up to the ac hoses. Upon closer looks, there did appear to be more debris and grains of sand caught in the fins. Here are some pictures:

https://www.amazon.com/photos/shared/cX ... Nf1r8t2h4m

https://www.amazon.com/photos/shared/X_ ... NRgwzx-KsU

https://www.amazon.com/photos/shared/vE ... f_kVzZT8iN

I took your word and sprayed the condenser and radiator fins down with degreaser and let it all sit for a while then I blew it all out with the garden hose and a good high pressure nozzle. I had good strong streams of water coming through the condenser fins. It was impossible to get the spray nozzle in between the condenser and radiator but I was still able to get plenty of water shooting through the radiator fins. I'm very confident that there is no clogging or airflow blockages through the fins of the condenser and radiator. For what it's worth, my engine has had no overheating issues even in the sweltering Houston heat.

You can see in these pictures that everything came out nice and clean:

https://www.amazon.com/photos/shared/26 ... _A7PlWVEfL

https://www.amazon.com/photos/shared/5Y ... U2mDrgcDHt

https://www.amazon.com/photos/shared/YF ... aVuDlv5smF

https://www.amazon.com/photos/shared/7n ... jsnINgdclU

[dannyual320]

So today my Mastercool 69110 recovery unit arrived. I pulled a vacuum on the tank and before I recovered the refrigerant, I decided to hook the gauges up one more time and take some readings.

My car was completely cold when I started and the ambient temperature was 88 degrees.

Cold engine

Idle.................................1500rpm
H135................................H155
L32..................................L34
Vent83F............................81F


Engine warming up but still not hot

Idle.................................1500rpm
H180................................H190
L34..................................L32
Vent78F............................78F

My evacuated recovery tank had a tare weight of 17.86 lbs. I hooked up the recovery machine and recovered my Trans Am's refrigerant and then weighed the tank a second time. The second weight was 19.51 lbs. My total recovered refrigerant was 1.65 lbs or 26.4 oz and my system has a specified charge of 24 oz.

Obviously there is something wrong with the system but at least we can rule out a low R134a charge.

https://www.amazon.com/photos/shared/MK ... HGM6jxqjtl

https://www.amazon.com/photos/shared/3z ... t3R-6MJHXU

[dannyual320]

I know it sounds like a "throw random parts at it" approach (i see it more as routine maintenance though), but now that the refrigerant has been recovered you could possibly replace both pressure controlling devices - the compressor's control valve and the orifice tube. Don't know how much of a hassle it's to get to them on that vehicle, but they're definitely cheap parts.

But i still think something's wrong with your evaporator.

When you charge it up again, get as close as possible to 24 oz, or even better let a RRR station equipped professional charge it up to the specified weight. The V7 system is unforgiving when it comes to charge weight.

I don't think that either of them would be that difficult. I know the OT is very inexpensive but I have no idea about the compressor's control valve. I'd certainly be willing to try replacing these items.

[dannyual320]

I know it sounds like a "throw random parts at it" approach (i see it more as routine maintenance though), but now that the refrigerant has been recovered you could possibly replace both pressure controlling devices - the compressor's control valve and the orifice tube. Don't know how much of a hassle it's to get to them on that vehicle, but they're definitely cheap parts.

But i still think something's wrong with your evaporator.

When you charge it up again, get as close as possible to 24 oz, or even better let a RRR station equipped professional charge it up to the specified weight. The V7 system is unforgiving when it comes to charge weight.

I'm going to admit right up front that I absolutely hope that this isn't the case. I hate having to pull a dash to get to evaporators and as meticulous as I am, the dashboard is never the same afterward. Lots of squeaks and rattles !

Here is the reason that I currently doubt that it is an evaporator problem: ac parts under the hood are not cold. The only cool part under the hood was just after the orifice tube right before it goes into the firewall. Cool but not cold. No other cool parts and no sweating on any parts.

With my ac scale I don't think that I'd have any problem charging exactly 24oz of refrigerant out of my 30lb bottle.