Fixing both the heater core and the AC

[Jay 535i]

I've got some kind of heater core problem because my windshield is fogging up and I'm getting coolant odour in the cabin.

My A/C also doesn't work at all, though I have no idea why.

Is there any economy of scope by fixing these two items at the same time?

[632 Regal]

did the ac ever work? have you had it charged or checked? if its not the evaporator leaking then you wouldnt need to touch it.

[Jay 535i]

did the ac ever work?.

Not in the time I've known the car, no. Presumably, it did work at some time in the past :)


have you had it charged or checked?

No, not yet. I'm broke at the moment, but obviously I would want to rule out the easy fixes before I start looking at hard ones.


if its not the evaporator leaking then you wouldnt need to touch it

Touch what, exactly? I really have NO idea why the A/C doesn't work. It just doesn't. The aux fan also does not work, which may or may not be related.

I'm just wondering if I'm going to have easy access to any A/C components while I have the dash apart. If not, then then I'll save the A/C for another day. After a lottery win, perhaps.

[genphreak]

Fans are activated by the AC and the thermo switch- my fan didn't work as the AC gas had dwindled away-or burned out somehow gradually. I just had it regassed and it now works fine on both speeds. No leaks!

I blamed the switch, the resistor, but it was actually that I was too lazy and cheap to regas it. The compressor can jam up due to non-use so you miight as well just get it done anyway. First step would be perhaps to check the switch's operation, then the resistor's connectivity (crumbs one has to pull apart the front of the car just to do that... :D), checking it requires pulling brittle clips and connectors, why try fixing (f*#@ing) it when it ain't broke?

I'd be tempted to just regas without doing any of that as it could be fine, just not running due to the gas.

Just my 2c. :) Nick

[Jay 535i]

I'd be tempted to just regas without doing any of that as it could be fine, just not running due to the gas.

I guess that seems like a reasonably place to start.

My father bought the car from an independent European used car showroom, and the A/C was not working at that time. If it's just a matter of recharging the system, then I'm surprised the dealer didn't do that, as they could've asked more for the car if it'd had working A/C.

I think Bruno has the recharge equipment...

[Paul in NZ]

and once you have it fixed dont forget to run the a/c at least 10 15 minutes a month.......In the winter with the A/C on(and heat of course) It demists the whole car in seconds,even with a slight heater core leak!

[SharkmanBMW]

if it was only recharging, the dealer would surely have done it!

Even the parts that were working when you bought it will likely be f*&ked if the ac has not been running for so long.
I spent a ton redoing my ac.

[pbrennan10]

I changed the evaporator in my W140 benz, about a 3 month job.

If you're having problems with both, i'd suggest changing everything while you're in there. I think it's always a whale of a job just to get to either and they're right close together.

[genphreak]

I guess that seems like a reasonably place to start.

My father bought the car from an independent European used car showroom, and the A/C was not working at that time. If it's just a matter of recharging the system, then I'm surprised the dealer didn't do that, as they could've asked more for the car if it'd had working A/C.

I think Bruno has the recharge equipment...Oh, I did repalce the drier as well- do they clog up? Maybe that was part of it...

[Jay 535i]

if it was only recharging, the dealer would surely have done it!

Even the parts that were working when you bought it will likely be f*&ked if the ac has not been running for so long.
I spent a ton redoing my ac.

Where do I start? Or should I just take it to an indy and hope for the best?

How ugly can this get?

[632 Regal]

as for the driers, the way to install them is to open the system and repair everything, then install the drier absolutly last, and as fast as possible evac the system, one hour open to the air is enough to ruin the drier and render it useless. If you installed it at home you probably allowed the drier to absorb and "fill" the drier before you took it in to have an evac and rechearge. The drier is supposed to absorb micro amounts of humidity remaining in the system not the whole neighborhoods...;) If you remove the caps to check it out before working on it it might have ruined it. This is why AC places charge so much.


Oh, I did repalce the drier as well- do they clog up? Maybe that was part of it...

[genphreak]

as for the driers, the way to install them is to open the system and repair everything, then install the drier absolutly last, and as fast as possible evac the system, one hour open to the air is enough to ruin the drier and render it useless. If you installed it at home you probably allowed the drier to absorb and "fill" the drier before you took it in to have an evac and rechearge. The drier is supposed to absorb micro amounts of humidity remaining in the system not the whole neighborhoods...;) If you remove the caps to check it out before working on it it might have ruined it. This is why AC places charge so much.Good advice Jeff- but I was lucky... ;) I paid someone else to do the recharge -and- change the drier :) Sorrry- should have said, but that is advice many of us could do with knowing in these DIY times...

[Jay 535i]

Thanks for all the feedback, guys. The A/C is sounding less and less like a DIY job.

I'll just have to keep saving up, or else sweat it out like last year. :)

[Robin-535im]

Thanks for all the feedback, guys. The A/C is sounding less and less like a DIY job.

I'll just have to keep saving up, or else sweat it out like last year. :)
I think the only A/C part that's near the heater core is the heat exchanger (reverse radiator) that sits just aft of the heater core.

I've done the heater core before and it's not hard, just takes time and attention to detail to make sure all the umpteen-odd different screws go back in their proper places. I only replaced the core and the o-rings, not the Al tubes that go through the firewall, and that fixed my foggies.

[Rigmaster]

Maybe some terminology will help here. The only part that's near the heater core is the AC Evaporator core (what Robin called the "reverse radiator"). It looks like a small aluminum radiator. The only reason you'd need to replace the evaporator is if it was leaking, and the only way to find out if it's leaking is to charge up the system and look for a leak- using a sniffer is the common method. It might be a good idea to try to have the AC diagnosed, just in case the evaporator needs to be replaced, you'll save yourself (or a paid mechanic) ALOT of time by doing them both at once- IF needed.

Most of the other AC parts (compressor, receiver/dryer, condensor, etc) are pretty easy to get to on their own. They can be REALLY expensive though- especially the compressor.

Bret.

[Blitzkrieg Bob]

I replaced:

The R134 & green dye. $75

Compressor leaked (green dye)

Replaced compressor & drier, refilled with R134 & more green dye. $300

Condensor core leaked tiny green spot from a slow leak, kept the system charged until I replaced it in flash and evac/recharge it. $200

I did it all myself, but you need a A/C mannifold set and a vacuum pump to do it right.

most shops will pressurize it and sniff or use dye to locate the failed part, but will offer little to no gaurentee unless they replace everything $$$$

[632 Regal]

I vacumed my truck overnight before I retrofitted the R34 with 409-A.
got quite cold indeed :D

I replaced:

The R134 & green dye. $75

Compressor leaked (green dye)

Replaced compressor & drier, refilled with R134 & more green dye. $300

Condensor core leaked tiny green spot from a slow leak, kept the system charged until I replaced it in flash and evac/recharge it. $200

I did it all myself, but you need a A/C mannifold set and a vacuum pump to do it right.

most shops will pressurize it and sniff or use dye to locate the failed part, but will offer little to no gaurentee unless they replace everything $$$$

[Blitzkrieg Bob]

isn't that a cleaner?

the A/c is streak free and lemony fresh?

[Kalevera]

Jay, a lot of this stuff has already been discussed, but let's beat it into the ground again and maybe a mod will move this into an archive section for future reference.

I don't really see the point in doing A/C repairs in the middle of winter, for a couple of reasons: 1) harder to diagnose the system if it is indeed an evap leak, 2) it's difficult to tell if the A/C is even working unless the ambient air temp is above 75 degrees farenheit, 3) replacing the condensor only means that it's subject to road salt and other damaging hazards before the system is even useful.

Read this: http://www.koalamotorsport.com/article-airconditioning.asp

First do a visual inspection of the system. Condenser leaks are common at the fittings (lower right hand side of the condenser). They're usually noticeable because the oil seeps out and propagates a dusty haze in the vicinity. Pop the radiator retainer clips/remove the fan shroud and fan and have a look at the condenser from behind if nothing is apparent when shining a light through the front. Lines will be harder to diagnose, but a visual check doesn't hurt anything.

If there are no apparent leaks, have a shop fill it with dye and about a pound of refrigerant, then have them check it with a UV light.

The process for checking the operation of the aux fan is covered in Bentley, but the fan isn't necessary for A/C operation.

There's a big gamble in resuming use of a system that's been depressurized for a while without replacing every component. The parts that haven't been replaced can fail, and it's not unheard of for e32/e34 owners to spend 2 or 3 grand to get cold air.

Tons of more info can be had with a search.

best, whit

[632 Regal]

cooler refridgerant!
isn't that a cleaner?

the A/c is streak free and lemony fresh?

[Blitzkrieg Bob]

it's sunny and 80 degrees everyday.

Baaaw haaaa haaa haa ha!

[Jay 535i]

Jay, a lot of this stuff has already been discussed, but let's beat it into the ground again and maybe a mod will move this into an archive section for future reference.

I don't really see the point in doing A/C repairs in the middle of winter, for a couple of reasons: 1) harder to diagnose the system if it is indeed an evap leak, 2) it's difficult to tell if the A/C is even working unless the ambient air temp is above 75 degrees farenheit, 3) replacing the condensor only means that it's subject to road salt and other damaging hazards before the system is even useful.

Read this: http://www.koalamotorsport.com/article-airconditioning.asp

First do a visual inspection of the system. Condenser leaks are common at the fittings (lower right hand side of the condenser). They're usually noticeable because the oil seeps out and propagates a dusty haze in the vicinity. Pop the radiator retainer clips/remove the fan shroud and fan and have a look at the condenser from behind if nothing is apparent when shining a light through the front. Lines will be harder to diagnose, but a visual check doesn't hurt anything.

If there are no apparent leaks, have a shop fill it with dye and about a pound of refrigerant, then have them check it with a UV light.

The process for checking the operation of the aux fan is covered in Bentley, but the fan isn't necessary for A/C operation.

There's a big gamble in resuming use of a system that's been depressurized for a while without replacing every component. The parts that haven't been replaced can fail, and it's not unheard of for e32/e34 owners to spend 2 or 3 grand to get cold air.

Tons of more info can be had with a search.

best, whit

Thanks, Whit!

I would wait until summer. I'm just asking now.

$2-3k is about what I figured. Not tempting, but worth it if I'm going to keep the car a while, which I plan to.

Thanks everyone.