Fixed My A/C. Now Some Questions - PeachParts Mercedes-Benz Forum

sailor15015 · #1 07-26-2006, 05:38 PM

I've been spending the last couple of weeks fixing my a/c after the compressor seized and snapped the belt. A P/O had converted it to r134a. I replaced the drier, expansion valve, new remanufactured compressor, synthetic BG Frigquiet oil, and thoroughly flushed the system. I also used Nylog on all the seals and put r12 back in. I took it to a shop to have it vaccumed down but I don't think they did a good job. They only pulled a vaccum for 20 minutes and I think they let all the air back in when the guy took off his gauge. Vent temps will get down to about 60°F within a minute, 50° after about five, and they'll only get down to 43°F, the coldest I've seen, after extended highway driving. These numbers came when it was 90-100°F outside, by the way. When idling for more than five minutes, temps will rise to 60°F, and the aux fan does come on. Does this sound right to you guys? Will it be worth the effort to take it to my indy and have him evacuate and pull a really good vaccum on it? I'm just glad its working but its been so hot, I'd be willing to spend the extra $$$ to get it colder. Thanks.

Matt L · #2 07-26-2006, 05:54 PM

If the vacuum wasn't pulled for long enough, damage may have already been done to the dryer. But perhaps not, and with R12 in the system, you aren't as hyper-sensitive to moisture anyway.

It does sound like it's undercharged. If there's incompressibles in there (i.e., air), this will prevent proper charging. Disconnecting the gauges before adding refridgerant sounds like a sure way to get some air in the lines.

sailor15015 · #3 07-26-2006, 06:13 PM

I put two 12 oz cans, one whole 14oz can, and enough of another one to get me two about the 2.9lbs. I don't remember the exact low and high side pressures but I do remember getting them dang close to the numbers on the chart at ackits.com. Oh yeah I do have one spot on my condenser that has bent fins, about a five inch circle, and several other spots where it looks like big bugs have bent the fins. Relative to the entire surface area of the condenser, it doesn't look like a whole lot but things like that bug me.

acehandy · #4 07-26-2006, 06:25 PM

Vent temps are relaitve to ambient. If you are getting oulet air temps 50 degrees lower than ambient, your system is running about as efficiently as it can.

sailor15015 · #5 07-27-2006, 05:05 PM

I did a little explorator on my condensor just now and it is pretty clogged with hair and gunk. I can't remember whose thread it was with the 120+ pics in it on evaporator removal but I read it last night and I was wondering, can the evaporator be left in the car and the box around it removed for cleaning? If so, I think I'll tackle that this weekend. I'm kicking myself now because I took my time all the way through this project, doing things like I shouldn, and I think not making sure that mechanic pulled a good enough vaccum may be hindering my system.

Hit Man X · #6 07-27-2006, 05:26 PM

Get the windows tinted, the sun hurts my eyes (seriously) so I prefer 5% back and 20% sides. 35% is legal limit in Texas for the fronts, but I've never been stopped for that. This will make the system work a lot better.

engatwork · #7 07-27-2006, 05:30 PM

Quote:

can the evaporator be left in the car and the box around it removed for cleaning

only if you plan on replacing the box.

sailor15015 · #8 07-27-2006, 05:50 PM

I take it part of it has to be broken then? I came across some posts about cleaning it with a home-made part out of a copper tube so I think I'll give that a try. I think my system is actually running good. Its 100 out and vent temps get down to 62 at idle after about a minute, 43 after about ten minutes of driving. I tend to nit pick at things. Instead of picking at the things that aren't perfect, I should focus on the fact that it works at all.

Tinting the windows sounds like a good idea. I carry out groceries all day long and I like the cars with dark windows.