when I rebuilt it last year, I replaced the compressor with a new (not
rebuilt) r4, replaced rear expansion valve, replaced orifice tube in the
front (I dont recall it being pluggd up). I also flushed everything
while it was torn apart. I removed the radiator as well to clean out
the crap between it and the condenser. I am recovering the refrigerant
now and will put in on a vacuum for an hour, then recharge it. See post
just a minute ago. It did run now, but acts like its overcharged or
something.
Peter Frederick wrote:
Did you flush the condenser and is it clear of debris between the radiator and
condenser? Sounds like what my TE does -- high side is too high and cooling is
inadequate with high pressure, and I'm quite certain the plugged up condenser
is the problem. If it's too hot from no air flow, the freon will not condense
properly, so you have both excessive pressure and lousy cooling from hot gas
instead of liquid at the orifice tube in front. If the expansion valve is
working correctly, it will be wide open, too, and again you get high low side
pressure from gas expansion rather than liquid boiling -- somewhat less cooling
capacity.
You must also evacuate for at least 45 min to remove air and water, particularly water, from the system -- R134a oils hold much more water than R12 oils, and it takes some time for them to evaporate and migrate out via the vacuum pump.
I found that flushing the condenser alone made a huge difference -- if the
system was ever R12, all the mineral oil will tend to collect in the condenser,
coating the inside and greatly reducing heat transfer.
Also, was the orifice tube clogged? If it was, did you put a filter in the low side
hose, and if so, have you replaced it? Slop in there will also cause high side excessive
pressure, and if the filter is between the fitting and the compressor, you can have a
vacuum between the filter and the compressor and high pressure "upstream" of
the filter!
Peter
-----Original Message-----
From: Mitch Haley <m...@voyager.net>
Sent: Jul 18, 2010 11:42 AM
To: Mercedes Discussion List <mercedes@okiebenz.com>
Subject: Re: [MBZ] I buy a new AC machine, now have AC problems
Kaleb C. Striplin wrote:
Its R134. got the spec out of the owners manual, there is no sticker
under the hood which is strange.
OK, sight window won't help much then. Was it always R134, or was the 4 1/4 lb
the R12 capacity? (remember to use 3/4 as much r134 as r12.
If it was working somewhat with 2.x in it and hydrolocks with 4.25 in it, I'm
still thinking you want less than 4.25.
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--
Kaleb C. Striplin/Claremore, OK
95 E300, 94 S500, 92 500SEL, 92 300SD, 92 300E 4Matic,
91 350SDL, 91 300D, 89 560SEL, 87 300SDL x2, 85 380SE 5.0 Euro,
85 190D, 84 190D, 84 300D euro manny, 76 240D, 76 300D,
http://www.okiebenz.com
_______________________________________
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