ac not cold enough?? please read this first before posting your questions.

before we get into the really hot weather and get a gazillion threads about ac repairs, please take the time to read this and use it as a guide.

i have done ac repairs for about 15 years, including many, many retrofits from r12 to 134a. i do not believe there will be much of that to be done nowadays, but in order to be able to do retrofits properly one needs to know about ac systems and how they function.

i do not claim to be the all knowing guru of ac work, and can only share my experiences and how i approach the repair of the system. i am sure there are some things that have malfunctioned that i have *not* repaired (yet), so if i have left your particular issue out please do not feel slighted. think of it as more of a comprehensive approach, similar to how a doctor visit is done, with the gathering of preliminary information.

in that manner, as a gathering of preliminary information, i have compiled a basic assessment proceedure.

note, i stated 'assessment', and not 'diagnostic'. without me actually being the one working on the vehicle, i cannot accurately diagnose anything. that being said, i hope to be able to assist as much as possible.

what you will need to do this should be:

r134a manifold guage set (for as much as you would be using it, a cheap set is fine)
thermometer (infra red temp gun is best)
testlight
safety glasses (more for actual repairs than troubleshooting, but always best to be safe)
r134a recharge valve (either the pierce type or the screw on type. i like the screw on type)
misc hand tools, screwdrivers, and whatnot to gain access to areas
flashlight

nice to have but not necessary:

vacuum pump (can probably rent one)
r134a reclaim/recharge station (yeah, right go to a shop)


with ac work i install a manifold guage set, then if the system shows pressure (ambient temp should = guage readings), i check to see if the system engages when requested.

if the compressor engages, then i check the vent temps on recirculate (max air) and *lowest* fan setting. i see what the vent temps are reading and compare that to the low side.

the vent temp should be about 10 degrees f (or thereabouts) higher than the low side. this is going to be in the 30's, so the vent temps should be in the 40's.

if the compressor cycles, then it should be the 'average' between on/off times (on @ 20psi / off @ 40psi = 30psi avg)

if this works fine, then leave it alone. on 90 degree days with 90% humidity *any* ac system will be struggling. check the fan clutch and condenser for restrictions or bent fins.

if it does not work as above description, then you need to trouble shoot.

if no pressure, or less than ambient temp reading on the guages, the system is pretty much empty, you need to find and fix the leak.

if pressure but no clutch engagemant on the compressor, check for power to the compressor. ****USE A TESTLIGHT*** not your dvom, ok....

if power, replace clutch.

if no power to clutch, check the low pressure switch for power. if power is present, jumo switch and see if compressor engages. replace low pressure switch if it does.

if no power is present, *then* check the fuse. if blown, replace and verify the compressor isn't seized.

if not blown then check the relay. swap it out with another relay and check operation. (iirc the horn relay is similar, but any relay that does not require the vehicle to run that is similar can be used)

or, you could swap out the ac relay with the fuel pump relay (iirc, they are similar?? i can't remember and i am not going to run out to my car to check, but if they are and you swap them out and the car still starts then the realy is operational)

if these all check out, then check the high pressure switch in similar manner as the low pressure switch.


if the compressor engages but the system does not get cold, check your reading.

if low side is the same as high side, then the compressor is not working. replace.

if low side is too high and high side is too low (as in reversed), or the high side goes into a vacuum, then there is a restriction. look for the frosty cold area right next to the really hot one. an infra red temp gun works well for this . repair as needed.



if the high side and low side are within parameters (i pay more attention to the low side as it is much more relative to the actual coolness coming out of the vents), but the vent temps are still too high, then check the settings.

do you have the climate control settings adjusted properly?? does the system operate properly on full heat??

if yes, then you may have a restriction in the airbox on the ac side. check the cabin air filter for debris, as well as the box itself. you may have a restricted evaporator.

if the system does not get fully hot (vent temps), then you may have an issue with the climate controls not setting properly. this part is very involved and will usually require some highly technical stuff, so i usually try swapping out with a known good unit to see if that fixes the problem and go from there...



seriously. i do. if you have a known good unit, or know of someone who does, it takes only a few minutes to swap them out and confirm.

if this does not remedy the ac issue, then there are some serious issues and i suggest going to a repair shop as i do not think that this will be any easier than what i have already covered. that, and i do not have the proper diagnostic charts in front of me to relay them in more user friendly nomenclature.


**regardless** of what repairs are being done, i always suggest a reseal of the entire system and accumulator, as well as fresh oil. and no, you do not have to disperse the oil throughout the system. it will get there on its own.

you *do* have to lube the compressor before installing it, though, as this is always to be considered dry when you get it. remember to measure your oil before adding it so you can ensure that you have as much of it out as possible. these things are designed to compress a gas, not the pag oil, k??


there. you managed to make it through. i hope that i did not confuse you to much.

if i left anything out that you wish to discuss or cover, please feel free to comment. this is sorta like putting in golf. there's much more going on that what it actually looks like, and so much of this sort of thing i have done for so long that i just do it without thinking about it.

feedback is always encouraged.





df

Much needed. Should be (yet another) sticky. So what if we have a bunch of 'em?

Personally I would like to see a stickied link to a full page of locked DIY's. Like they have on BF.c.

No reason that we need to continuously link our members over there, when we have the knowledge experience, and guides already written up on this forum.

To get that done though, I think that we will need to have an E36 moderator.

Yea I need to look into mine the SoFla heat is coming and it's already challenging my a/c's fortitude and the a/c is intimidated

Orrrr just delete the A/C and think nothing of it!

Ya don't do that where I live. It had already hit 90* here before the first day of SPRING! Gonna be a miserable summer. Much more so with no AC.

Im still trouble shooting the x5 a/c...getting on my nerves

Originally Posted by jonesin

Personally I would like to see a stickied link to a full page of locked DIY's. Like they have on BF.c.

No reason that we need to continuously link our members over there, when we have the knowledge experience, and guides already written up on this forum.

To get that done though, I think that we will need to have an E36 moderator.

The other series on here have a seperate forum for DIYs only. I always wondered why 5, 6, 7, 8, and //M cars had separate forums for DIYs and the 3-series didn't...

Originally Posted by B1MM3R

Im still trouble shooting the x5 a/c...getting on my nerves

wanna pm me some details??



df

90* here today... My a/c was struggling around noon
smh it's gonna be a long hot summer

time to bump this thread....


can we get this added to teh stikiez???





think this should be at the top for a bit, though...






df

+1! The "My AC isn't (fill in the blank)" threads have really started popping up now.

I haven't had AC since I bought the car. Its been 90 plus every day for the last month or so. And up until replacing the regulator a week or so go, my drivers window didn't go down.

Not concerned. Like a boss.

Los, you've fried your brain....like a boss.

I don't know how you guys stand it with no A/C. I'd have to hang my head out the window like a dog to get cool enough if the A/C isn't working.

figured i'd bump this up since we'll be getting warmer and warmer over the next few weeks.

hopefully we can avoid a million 'my ac isn't working' threads....

feel free to drop me a pm if you need any clarification on my notes.



df

I'll be consulting this soon, my AC isn't even attempting to be cold.

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I thought you didn't need A/C in the Perfect Climate State.