Cleaning evaporator and heater core

[KeithW '91 535i]

I can see that the heater core or a/c evaporator right behind the motor is quite blocked with material, the fins are partially visible here and there. Question- Is there a safe solvent that I can spray/apply from the engine compartment side that is effective and will increase air flow? Please respond ASAP as the car is apart right now!
Thanks! This is the car that has possible Relay Module related issues that keeps the windows from going down, so I need the fan to get back on-line until I can determine the problem. THANKS to Don Gale for the tip and part number so I buy the Stabilant 22A electrical contact cleaner at a VW Dealer ($40 in stock for 5ML). And for the Amsoil, too! Gale is great to deal with!
Keith in AZ.

[e34bim]

Wd40

[bimmerd00d]

is it the heater core, or the microfilter you see? ;) If it's your microfilter, just remove the sucker and replace it

[Bill R.]

have a bg distibutor in phoenix. Don't even think about wd40 unless you really want the pleasant smell of wd40 every time you turn the heater or a/c on...

[/QUOTE]bg stuff (http://www.bgprod.com/bgprofessional/bgproducts/aircon.html)

[Javier]

http://www.bimmer.info/forum/showthread.php?postid=52591#post52591

[Bill R.]

sprayed the cleaner in the wrong place, If he cleans the evaporator or heater core from the blower side and lets it dry ,there won't be any problems .

[KeithW '91 535i]

is it the heater core, or the microfilter you see? ;) If it's your microfilter, just remove the sucker and replace it

My '91 535i does not have the microfilter you speak of.
I can see the heater core, in all its filthy glory plain as day right behind where there blower motor is mounted. So far, I have been pretty successful with a stiff brush and a vacuum cleaner...tight quarters and my hands have paid the price. Thanks for the suggestion!
Keith

[KeithW '91 535i]

Wd40
I have removed most of the build-up with a brush and a vacuum cleaner. I was tempted to try your suggestion, but worried that by introducing a spray that would stay on the fins it would collect more dust, etc at an even greater rate than a dry, non-coated surface. Am I wrong?

Keith

[KeithW '91 535i]

sprayed the cleaner in the wrong place, If he cleans the evaporator or heater core from the blower side and lets it dry ,there won't be any problems .
I will try to get me some before I button it up. I already did pretty good so far with a stiff nylon bristle brush and a vacuum cleaner. If the heater core was nearly blocked and filthy, I wonder how the evaporator looks. That looks like a lot of work to get after it, so I will hope for the best right now. So far, in the summer, I have measure about a 5 degree temp difference between the left and right side vents, the left being warmer. I replaced the electonic heater valve with new without any change in results last summer. Wonder if this blockage had anything to do with it. It never did blow the volume of air like my E32 does (replaced the evaporator 7 years ago because of leak, not clogged). I did happen to see a really clogged evaporator from a car owned by a dog fanatic that obviously shedded lots of fur in the car.

[Javier]

is the product he used for the job, may be a good choice!!

Javier

[Bill R.]

spray cleaners are designed for. When the dust ,dirt, mold etc mixes with the moisture thats always condensed on the evaporator it forms a gunk thats pretty hard to get off without the spray cleaners..You can get access to it by removing the glovebox and taking off the cover where the sword would normallly live, I don't think you have a sword but the cover should be there.










I will try to get me some before I button it up. I already did pretty good so far with a stiff nylon bristle brush and a vacuum cleaner. If the heater core was nearly blocked and filthy, I wonder how the evaporator looks. That looks like a lot of work to get after it, so I will hope for the best right now. So far, in the summer, I have measure about a 5 degree temp difference between the left and right side vents, the left being warmer. I replaced the electonic heater valve with new without any change in results last summer. Wonder if this blockage had anything to do with it. It never did blow the volume of air like my E32 does (replaced the evaporator 7 years ago because of leak, not clogged). I did happen to see a really clogged evaporator from a car owned by a dog fanatic that obviously shedded lots of fur in the car.

[KeithW '91 535i]

Thanks again, Bill R.
I found the BG product via special order at my local NAPA store in Scottsdale. It costs $40.00. NAPA says their BG products are really very good. Fuel injection cleaner is the only BG item they stock. I did order the Frigi-clean (part #709 from BG) and it will be at NAPA within 24 hours. Thanks for the tip on reaching the evaporator, too. I will do that and can't wait for summer (the only good reason I have) to see if there is a gain in a/c performance. Have a great day! Keith


spray cleaners are designed for. When the dust ,dirt, mold etc mixes with the moisture thats always condensed on the evaporator it forms a gunk thats pretty hard to get off without the spray cleaners..You can get access to it by removing the glovebox and taking off the cover where the sword would normallly live, I don't think you have a sword but the cover should be there.