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How to do an A/C Flush on 1988 535is?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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lswoboda
Posts: 57
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

How to do an A/C Flush on 1988 535is?

Post by lswoboda »

Hello:

I’ve been searching and reading a lot about how to work on our air conditioning systems, but I haven’t seen anything on how to effectively flush air conditioning system on an e28.

I am re-doing my A/C system with a kit from Austin at ACSolutions, and part of the procedure is to flush the system.

YouTube makes an A/C flush look easy, but can anyone share any guidance or tips to do this correctly on an e28?

Since I’m replacing the condenser, the compressor, and most of the hoses, I need to focus on flushing the evaporator and a line or two that will be re-used and I don’t know where to start.

Thanks in advance.

LS
harrypalmer
Posts: 531
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: How to do an A/C Flush on 1988 535is?

Post by harrypalmer »

Bump as I also want to know for the same reasons.
Federico
Posts: 352
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: How to do an A/C Flush on 1988 535is?

Post by Federico »

At the stage you are at, I'd go for the full monty: pull the evaporator, flush it and replace the TXV, and also pull the heater box and replace the rotten foam.
Or, at least pull the evaporator box, the fins are probably stuffed with lint and crap anyway.
lswoboda
Posts: 57
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Re: How to do an A/C Flush on 1988 535is?

Post by lswoboda »

The PO of my car did the heavy lifting on the A/C, so I don’t have to open it up.

I’m updating the A/C and want to do a simple flush. It looks straightforward (per YouTube), but any tips that any one has would be very helpful.

Thanks.
Federico
Posts: 352
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: How to do an A/C Flush on 1988 535is?

Post by Federico »

There's no practical way of flushing the evaporator with the txv installed.
If the system was in good shape to begin with and your compressor didn't seize, just skip the evaporator flush.
gadget73
Posts: 527
Joined: Nov 22, 2017 11:30 PM
Location: New Jersey

Re: How to do an A/C Flush on 1988 535is?

Post by gadget73 »

typically if the system is going to have garbage in it, you'll find it in the condenser. Blow some air backwards through the old condenser and see if any garbage comes out. If thats clear and the compressor didn't fail, the evap is likely fine.
demetk
Posts: 8189
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: How to do an A/C Flush on 1988 535is?

Post by demetk »

If I'm not removing the TXV I'll flush the evaporator in both directions so I can get the old mineral oil out.
lswoboda
Posts: 57
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Re: How to do an A/C Flush on 1988 535is?

Post by lswoboda »

demetk wrote: Aug 05, 2020 9:53 AM If I'm not removing the TXV I'll flush the evaporator in both directions so I can get the old mineral oil out.
Demetk, do you do this with the TXV and the evaporator in the car? If so, can you share some tips on how you do it?

This is exactly what I need to do.

Thanks very much.
harrypalmer
Posts: 531
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: How to do an A/C Flush on 1988 535is?

Post by harrypalmer »

lswoboda wrote: Jul 31, 2020 9:45 PM Hello:

I’ve been searching and reading a lot about how to work on our air conditioning systems, but I haven’t seen anything on how to effectively flush air conditioning system on an e28.

I am re-doing my A/C system with a kit from Austin at ACSolutions, and part of the procedure is to flush the system.

YouTube makes an A/C flush look easy, but can anyone share any guidance or tips to do this correctly on an e28?

Since I’m replacing the condenser, the compressor, and most of the hoses, I need to focus on flushing the evaporator and a line or two that will be re-used and I don’t know where to start.

Thanks in advance.

LS
Is your car's AC system on R12 or R134a? This is crucial, as (is either my correct understanding or not) the hoses and specially the seals needed to run R12 need to be precise for that particular gas, as R134a molecules are either smaller or larger, eventually leading to exit the system.
Also have read elsewhere in this Forum TXV are particular for each gas, and if that's the case the R12 TXV is NLA. Someone please correct me here please.

Hope you don't feel I'm high-jacking your thread, just looking for comprehensible answers to your questions, as well as mine. My car is a 86 535i with R12 in the AC system BTW.

Regarding the system flush, found this for E12's that otherwise might be helpful http://www.firstfives.org/faq/AC/ac_charge.html
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