A/C warms at idle

[akorcovelos]

Hey all, having a stumper of a problem.:confused:  I bought my '91 318i about a month ago, and have since replaced all the v-belts, thermostat, and fan clutch. I also flushed the coolent and replaced with BMW brand. The only thing not working in the cooling system is the aux. fan in front of the radiator, which I plan on fixing asap. However, when I run the A/C it blows cold as ice when I'm crusing above 25-30mph, but when I'm sitting at idle it starts warming up. Could the belt be slipping, I don't hear any squeeling. When I'm at idle the coolent temp also starts creeping towards the red, but I'm sure thats due to the non-functioning aux. fan, could that cause the A/C to warm up as well? Just can't get my head around this one, I know you guys must have run across this before. Sorry for the long winded description, and thanks in advance for the help!:D
p.s. sorry for the crappy pic, i'll post some better ones soon!

[Wizard]

My aux fan also does not work.....I have the same issue as you....When the car is sitting my A/C does not cool....As soon as I start moving again the A/C seems to work fine......I though do not have a problem with my engine temp rising....Getting your aux fan to work (or replace it) should help the A/C issue...
I would say if your engine temp is rising that would be the clutch fan....Could be a loose belt but unlikely as I think that belt also runs the altenator...

[akorcovelos]

thanks wizard, I'll see if my A/C issue is solved by getting that aux. fan working. I don't think the temp rising is due to a bad fan clutch as I just replaced it a week ago. It was a used part, but it came with a lifetime warrenty, and when I compaired the two you could tell the new (old) clutch was much stiffer than my worn out one. I'll give the new one the "magazine" test and post the results.

[silverblades181]

the aux fan's purpose is to cool down the A/C condenser....it's normal it heats up at idle as the air flow is no longer sufficient to cool it down. As for the coolant temp nearing the red.....get this fixed asap....an overheating engine is very very bad, and no it's not caused by the aux fan, I removed mine aswell as all the A/C components and my engine never goes past the 1/2 mark, where it should be. Could be the fan clutch...or your coolant temp sensor..I think lol

[e30boarder]

i had the same prob with my 318... if i wasnt cruising, the temp gauge would sit around the 3 quarter mark. i had a mechanic look at it and we checked all the temps under the hood and none of them exeeded 200 degress, so we both figured it was ok. i later had some oil leak problems from a bad gasket and some overheating problems from not enough coolant in the radiator... i had a bad hose. im worried my head is cracked, thats why im interested in an engine swap. i want to start over fresh. the engine has almost 190k on it. the whole oil issue roasted my cams too... i already bought new cams and boxes, i just havent installed them. too busy with school and a lack of money doesnt help either

[D. Clay]

Although the overheating is serious, that problem with the A/C fan cost you too. While no air is passing over the condensor it is setting there building up head pressure or some kind of A/C lingo like that. Anyway, it'll take your compressor to the A/C rebuilders who will call it a core. Then it's while you're at it time for converting to R-134 because you just lost $100 worth of Freon-12 and no guarantee without a new dryer, system flush, etc. You can buy cans of R-134 like you used to buy Freon-12 before it was put on the endangered species list. The conversion saves you money and makes A/C a DIY.
Or fix the fan quick!

[e30boarder]

i already changed the ac over... the mechanic that looked at it changed it over for me. so ur saying i hav to get my ac compressor rebuilt?

[Deutschbag]

Strange, my AC gets warm at idle too, but my fan works and my coolant rarely gets above half way.

[D. Clay]

" Or fix the fan quick!"
You'll definately know if the compressor needs rebuilt. It won't cool no matter what, you'll lose freon, and there'll be A/C oil all over the clutch. The fan on E30's is just barely adequate at idle. If it doesn't work at all, then the compressor is at risk of  "blowing out" seals. I can put a shop fan in front of my car at idle and the temp of air coming out of the ducts goes down.   Somebody usually says their E30 cools like a Toyoto Camry and that there must be something wrong with mine. It's been 100 degrees here for two weeks - dark tint is not an aethetic decision, it's a survival skill.
On my list of to do's is a 2000+ CFM pusher in front of the A/C condensor.
I know a fellow in Florida that has pusher and puller 2200 CFM's for rush hour traffic.

[akorcovelos]

ok, tested the "new" fan clutch and it passed. The only time the coolent temp goes beyond half way is when the car is at idle or crusing below around 25mph with the A/C on, no A/C and coolent temp stays where it should. Obviously the aux. fan not working must have something to do with this right? From how it looks to me, that aux. fan doesn't even blow directly on the A/C compressor, but is mounted on the front of the radiator. I plan on replacing the aux. fan temp sensor with one that kicks on at lower temps. Any suggestions on the easiest way to test to see if the aux. fan is toasted, or if it's something else in the circut? Thanks for all the help!:)

[thumper3ld]

didnt read all the posts so if this wasnt suggested already, try jumping the aux fan so that it runs on high speed when you press the ac button.

[akorcovelos]

Hey Thumper, think you can post how to jump the aux fan to only run on high?

[D. Clay]

Hey Thumper, think you can post how to jump the aux fan to only run on high?

I would also like to know how to do this.

"From how it looks to me, that aux. fan doesn't even blow directly on the A/C compressor, but is mounted on the front of the radiator."

When the A/C fan doesn't work, it fails to cool the freon in the condensor. That results in excessive pressure that is bad for the compressor. It's not a question of cooling the compressor.

[thumper3ld]

Hey Thumper, think you can post how to jump the aux fan to only run on high?

I didnt do it myself, a friend of mine hooked it up for me. I'll take a look and take some pics if the weather clears up over hear.

[m42 fan]

I'm also interested in this.  I'm having similar symptons, ac blows cold while moving, warm wile sitting/moving slowly.  It wasn't as big a deal until I got here in Florida, where it's like 1,000 degrees, even at Midnight.  

Brian