2nd Gen Non-Engine/Transmission AC gets warm at stop light

[Deezul1]

The AC gets nice and cold when moving but warms quickly when sitting at a light. Sometimes I can hear the compressor cycle and it stays fairly cool but others its not working right. I have had it to 2 shops and both of them ran water over the cooling fins and checked pressures and said its fine. This truck never gets warm enough for the fan clutch to engage but it was replaced with a Hayden unit a year ago. Any ideas?

Thanks

John

 

[ToolManTimTaylor]

Sounds like a fan clutch. A Low charge would yeild a frozen coil or somwhat cool air all the time however 134A is funny that way. Has the system ever been opened before? Is the condensor clean?

 

[Deezul1]

When the shops checked it they said pressures were fine. It has not been opened since I have owned which has been 2 years but has had this problem the whole time. Condenser has a few bugs but otherwise is clean.

 

[The patriot]

My A/C always cooled better while it's moving. Got to have some flow over the condenser to make it work well. I've considered an electric fan so that it cools better when I'm not moving, but never followed through on it. It's just not that big a priority for me.

Eric

 

[ToolManTimTaylor]

John I read your post wrong I thought it said it quickly gets warm. Theese systems will warm a touch when stopped but you shouldn't loose it all together. If you haven't allready done so take some readings with an el cheapo digital thermo or something of the like in the center vents a/c on max and fan in the #2 position. Take readings cruizin and stopped . If memory serves right a 12 degree rise is threshold.

 

[ToolManTimTaylor]

Originally posted by The patriot

It's just not that big a priority for me.

Eric

I believe it. You have to worry about a military aircraft wing tip in the condensor where you are.

 

[The patriot]

Yea. I got to try to get a pic of that.

The sign makes you think it's something from the skunkworks that's gonna barnstorm ya. Theyre transports and tankers.

Eric

 

[kaffine krazed]

Look at the front radiator fins using a flashlight between the CAC and radiator to see if it is plugged.



What temps are you getting at speed and at idle. Do you know what the pressures are?



Try putting water on the condensor while idleing the truck and see if the temps drop. Also try increasing the engine rpms at a stop and see if it cools better.

 

[Dan_69GTX]

I agree with kaffine krazed.



If your temps get better at a stop with the rpm increase your compressor may be going bad.



When taking pressure readings, many shops will run the engine at operating rpm to check - not at idle. If at idle your readings are low or your gauge bounces you may have a worn compressor or if it bounces a bad valve in the compressor.



Let us know what you find.



Dan

 

[jrollins]

just a FYI as a general rule of thumb R-134A isn't as efficient as its older counterpart R-12, but i personally don't have allot of issues with my 01. 5 but i know some vehicles handle it better than others, i know GM has been battling this problem since they introduced the 134A systems in all there vehicles.

 

[E7mack96]

our 2001 durango has the same problem.



Kerry Dodge has had it in 7 times now for the AC.



It is there even as I type this. It has not worked since we bought it.



They have replaced the fan, the fan clutch, the relay, blew, and recharged, added dye, ect. It still won't work at a stop. Gets to 90 degrees at an idle, and cuts in and out cruising. It sometimes pulls to 60 degrees.



Every summer, they have it for weeks at a time, But we get a nice loaner with working AC.



The only good part is no miles on our vehicle, instead, it is theirs.

 

[Deezul1]

I checked the air temp at the center vent today while running around town and got 34deg but of course the warming at a stop lght didnt happen now that I have all these things to check out. I will check that the next time it happens. One shop checked at 2000 rpm and ran water over it and the other shop checked at idle and then at higher rpm while running water over it both times and the pressure readings were where they were supposed to be both times I was told the system was in good shape (musta been, they didnt try to sell me anything). It doesnt do it all the time and there doesnt seem to be any reason as to when it does it.

 

[E7mack96]

update!

Kerry just called,



They say that the dessicadent (sp) in the receiver/dryer came apart and clogged the line, and the r-134a was venting out the high side pressure refeif valve.



I did not know it had one, and I work on AC systems.



Anyway, they say its' fixed again, and to come and get it.



Maybe your receiver/dryer is bad too.



E7

 

[Huff N Puff]

It's the fan clutch or the blow by vent

That has sludged up the inside of the radiator with a slim that prevents air flow to the fan clutch to heat it up Its the fan clutches job to cool the condenser down when the truck is not moving fast enough to move air through it. The fact that when you cool down the condenser coils with water brings down the pressure confirms that you are not moving enough air thru the condenser to cool it down. Look inside the radiator to see if an oily slim is coating the radiator. If it is coated the only way to clean it out is to remove the radiator and steamclean it or clean it with a solvent. Merv

 

[Dan_69GTX]

OH YEA - NOW you tell us this is intermittant. If it was intermittant you don't have a problem with the amount of freon in the a/c and you "probably" don't have a problem with the compressor either.



Now I would check some different things:



1. At an idle - what is your vacuum reading? The heater and a/c ducts are controlled via vacuum - make sure your vacuum is good at idle - to the a/c system - not just in the main vacuum line. Make sure your vacuum lines to the a/c system aren't kinked. Since your sig shows you haven't done anything in the engine compartment - it could be possible that happened.



2. When it warms up - make sure the compressor is running. If not - check to make sure connections at the compressor clutch relay are good - you might also have a bad relay. (when the engine is running faster RPM you generally have the alt giving out more power - with a/c on and fan on high - and other draws - the current might not be good enough to operate the relay).



Start there and let us know. If you want to talk - PM me and I'll send you my number.



Dan

 

[Deezul1]

Thanks guys for a lot of helpful info.



Dan Thats a good thought on the voltage at idle, I will check that though bringing up the RPM at a stop doesnt seem to help.

 

[Huff N Puff]

Sounds like the highpressure shutoff switch

is cutting of the compressor cause pressures are getting to high. If you cool down the condensor will the compressor stay on is the way to test it. Check your high side presures see how high they go before the compressor shuts of if it gets to about 350 to 400psi you have an over heating condensor if it shuts down before that you might have a bad high side switch. Merv

 

[Deezul1]

Well ya,all musta scared it half to death as its been behavin pretty good lately. I have been paying real close attention to whats going on when the warming starts and it seems to be happening most often when sitting at a stop light shortly after the truck has been sitting for a while like leaving the parking lot from the movies and hitting a light in 2-3 blocks. The voltage meter stays steady at 14-14. 5volts and the vents are not defaulting to defrost which I believe is what happens when vacum gets low. I havnt put a vacum gauge on it though. It will get as low as 30deg at the center vent just running around town but the warming trend runs it up to 65-70deg, this is measured with a digital thermometer at 2" from the vent.

 

[SBradshaw]

Deezul1, I thought I was the only one with this annoying problem. Driving down the road the air blows ice cold around 38* but sometimes coming to a light it starts blowing warm moist air, start driving again and it cools down. This doesn't happen all the time but enough that it is a problem living here in Texas! I would rather fix this myself if at all possible... someone out there has to know the fix for this. Help!:{ :{

 

[Deezul1]

SBradshaw

I am thinking of installing an after market electric fan if I can find one thin enough to fit on the condenser and not hit the grill when the hood comes down.