Air conditioning RE-install

[longtallsally]

Hi All, I'm brand new to the forum and will be picking up a '91 318is on Tuesday.  The car is pretty well sorted save one thing (and it's kind of a big thing to me); the AC doesn't work.

I'm pretty savvy with cars and know the E30 pretty well (had 3 M20s) and even know basic principles of an A/C system.  However, I think this one might hurt pretty bad.

The guy I am buying the car from said that when he bought the car ~2 years ago, the system "needed a recharge".  Well he was planning on turning it into a track car and proceeded to pull the compressor off.  :mad:  I have no clue why people do this- 5 lbs. and negligible drag on the motor is not smart IMO.

Anyway, when he pulled the compressor, he didn't block off the lines that I could see.  Again, :mad:

So my question is this, am I screwed and I'll just be replacing all the lines in the system, the evaporator, expansion valve, and of course the receiver dryer due to the system being exposed?  Or should I roll the dice, slap the compressor back on (which I think is functional) and get it charged up with R134a in addition to the obvious rec/dry replacement?

I am thinking at the least I'll have to do the lines out of the compressor and to the rec/dry, but do you think I might have contaminants in other parts of the system as well thus necessitating this being a LONG and pretty pricey endeavor?

Not having A/C is not an option as this will be a daily driver and I've never worked on an A/C system, so I'm looking at it being a learning experience and should have all winter to get it fixed.  I'm getting what I think is a fair price for the car despite this, so it's still worth it.

Once I pick it up I'll post some pics.  Thanks for any help.

[longtallsally]

So I just did some research, and it seems like I might get "relatively" lucky.  An article I just read spoke about pulling a system out of a junk yard and getting it to work.  Well shoot, that is more or less what I'm up against.  It sounded like the worst case scenario is that the corrosion in the lines could circulate and gum up the condenser.

Along the lines of the condenser, in my last E30 325is, I had it converted to R134a for little cost and all that was done was the rec/dry and a good vacuum pulled and it was so cold that I rarely even had the blower on (just the sliders) so that was definitely money well spent.  And I just verified that the condenser is the same as the 325, so with that logic, it seems that the system can be as efficient.  I also found a place where a brand new condenser can be had for under $150.

That being the case, and the fact that it seems it is possible to have the system "flushed", it sounds like my biggest costs will be have the vacuum pulled and new refrigerant put in on more than one occasion.

Am I being overly optimistic?

[longtallsally]

OK, so I continue to research- yes I know it is silly to have a conversation with myself, but I find out a lot of information from forums like this, and when I find out info that I couldn't find in a search of the forum, I try to expand the community knowledge, even if it is trivial.

So I've found that the majority of parts for the AC system between the 325 and 318 E30 cars are the same.  That greatly widens my search if I end up needing to get used parts in the process of fixing the system.

[B318M42W]

great info! keep us posted as I'm sure some members around here are trying to get their A/c to work as well...

and also Welcome to the forum!

[AcSchnitzer318is]

Fingers crossed for you that a flush and vacuum pull/recharge will do the trick for you.  Worked for me, but my system was only open for 3 months, not 2 years.

BTW, the compressor is heavier than 5lbs... probably closer to 15lbs.  And if you pull the condenser and everything else AC related you probably approach 40 or 50, possibly more.  Don't know exacts because I would never pull an AC system since our summers routinely hit 105.

[longtallsally]

Fingers crossed for you that a flush and vacuum pull/recharge will do the trick for you.  Worked for me, but my system was only open for 3 months, not 2 years.

I was just doing more research and found that a true flush means to disassemble the system and only flush certain components.  You are never to flush the rec/dry (I guess that is kinda obvious), the compressor, the expansion valve, or any other components with a muffler or a filter on them.

So that said, it seems that I should start by removing some hoses and lines and the condenser from the engine bay (as it doesn't seem that anything in the cockpit should be flushed), get the flush stuff and do that and then replace with all new O Rings and add the retrofit kit.

If I'm feeling sassy, get the manifold gauge kit and pull a vacuum and see what I can see.  By this time, I should have taken care of a lot of leaks and my issues become more around electrical and/or the expansion valve.

This of course is all conjecture until I pick up the car and quickly test the compressor to see if the clutch will even engage.

BTW, the compressor is heavier than 5lbs... probably closer to 15lbs.  And if you pull the condenser and everything else AC related you probably approach 40 or 50, possibly more.  Don't know exacts because I would never pull an AC system since our summers routinely hit 105.

Yeah if I was making a dedicated track toy and was pulling the system, I'd pull the WHOLE system, not just be lazy and pull one component.

[twright]

It's probably not as big of a deal as you are worried about.  The system is relatively simple and only contains a few components: compressor, evaporator, condensor, expansion valve and receiver  dryer.  Put a new receiver dryer, expansion valve and compressor on it.  

If it holds a vacuum, you're good to go.

By the way, the compressor on a 1991 318is did not have the same compressor as two other 325 e30's that I have owned.

[doitover]

What I thought also, I just looked at some part numbers a couple of weeks ago when a e36 compressor from a 6 cylinder came up here on ebay. I didn't spend much time on it but it looked like the 4 cylinders use a different compressor?

It's probably not as big of a deal as you are worried about.  The system is relatively simple and only contains a few components: compressor, evaporator, condensor, expansion valve and receiver  dryer.  Put a new receiver dryer, expansion valve and compressor on it.  

If it holds a vacuum, you're good to go.

By the way, the compressor on a 1991 318is did not have the same compressor as two other 325 e30's that I have owned.

[longtallsally]

It's probably not as big of a deal as you are worried about.  The system is relatively simple and only contains a few components: compressor, evaporator, condensor, expansion valve and receiver  dryer.  Put a new receiver dryer, expansion valve and compressor on it.  

If it holds a vacuum, you're good to go.

By the way, the compressor on a 1991 318is did not have the same compressor as two other 325 e30's that I have owned.

Sorry, yes I should have mentioned that I think the compressors are different, but other major components such as the receiver dryer, evaporator, exp valve, condenser are all the same. The lines in the bay will obviously be different as well.

Should I replace the O Rings in the system?  And do you think it worthwhile to remove and flush the components I can?

[longtallsally]

I should have updated this sooner, but I did a thread a while back on E30tech:

http://www.e30tech.com/forum/showthread.php?t=82528

Here are the cliff notes:
1- Made sure the compressor clutch worked
2- cleaned up the compressor
3- removed all lines and flushed them
4- install ALL new O Rings, rec/dryer, and expansion valve
5- reassembled and did a simple pressure test then pulled a vacuum
6- Epic fail when the low pressure line going from the bay to the cab and the expansion valve blew very spectacularly
7- cool off for a couple months from being so angry

8- finally replace line that was bad and pull another vacuum
9- yet another epic fail as now the gasket from the top of the compressor where the lines hook in blew it seems

So my next move is to remove the compressor and put on a new gasket (essentially a new O Ring), and another rec/dryer, pull another vacuum and try again to recharge.

This time, if it doesn't work, then I'm going to let a shop at least diagnose the problem(s) but I can't see there being much more that could be wrong...