A/C Issues

[dawgz83948]

Hi everyone. I'm new to the forum (though God knows not new to the do it yourself or parts section of this site) and had a question for the experts here.

I have a 87 300D. The issue I'm having is two fold and not related (best I can guess).

Issue 1) If I leave my car outside, 70% of the time my Heater and fan will not work. If I drive on it for a 20-30 minutes, pull over turn off and restart the engine, everything works well again. If I leave the car in the garage it will work 100% of the time.

Issue 2) New issue, I tested the A/C system 1 month ago and it froze me out of the car. Today I try it on the way home and it only blew warm air. A bit of trouble shooting: If I turn the HVAC system off wait a bit and turn it back on the system blows hot air and then gradually gets cooler and cooler until warm air comes out. I verified that the Compressor is running. If this was any other car I'd assume the blend door isn't closing, but heaven forbid that the Germans leave a simple system simple. (My 240d was the best, all mechanical) Is there something I should look at that will help me. It gets about 105-110 in a few months here.

I appreciate the help......

[Merk]

I just bought a 1983 240d from a 91 year old lady with all records and the a/c didn't work so I reviewed the records and they spent over two grand on a a/c system. They did a recharge ever year after that too well not me I took the caps off the ports and got lucky I saw a little leak from the value core and replaced it. I then went to harbor freight and bought a a/c vac and gauges. I put a vac at 29 mlb on it and it held. I then put 2oz of meneral oil with die and 2 two cans of frez 12 in it. How cold it is. If all else fails put the die in it and find out where it is leaking and replace o-ring.

[dawgz83948]

Thanks for the reply. So I figured the vacuum dashpods were bad and were causing the issue I was having. I spent about 6 hours removing the dash, replacing the pods, and reassembling everything (although there are 2 screws left over that I couldn't figure out where they went). That fixed my front vent issue (knew it would) however the outer vents still stay warmish. I verified that the monovalve is getting 13.3v on the cold setting and 1-2v on the hot setting, however it may be weeping hot coolant into the heater core. I think that'll be my next replacement part.

I still have no good info on my #1 issue.

[Ferdman]

Check the 30-amp strip fuse on the driver's side strut tower. The fuse is inside the black plastic enclosure. Typically the fuse develops a hairline crack that becomes obvious when you remove the fuse.

[dawgz83948]

Originally Posted by Ferdman

Check the 30-amp strip fuse on the driver's side strut tower. The fuse is inside the black plastic enclosure. Typically the fuse develops a hairline crack that becomes obvious when you remove the fuse.

This fuse is in the main fuse box or under the plastic surrounding the fusebox?

[Ferdman]

Normally the 30-amp strip fuse is in a small (approx. 1" x 1" x 2") black plastic enclosure atop the driver's side strut tower in front of the main fuse box.

[dawgz83948]

Originally Posted by Ferdman

Normally the 30-amp strip fuse is in a small (approx. 1" x 1" x 2") black plastic enclosure atop the driver's side strut tower in front of the main fuse box.

Found it thanks. I removed the screws and the fuse, it appears to be intact.

[johnflight1]

For issue #1 I would look at the ignition switch. I had the same problem and I noticed one day when I wiggled the key with it running the blower came back on!.............Worth a try

[dawgz83948]

Well good news the mono-valve replacement fixed the problem. The A/C is now ice cold from all vents.