I was driving the wife's "new" 81 SD yesterday. I noticed at low speeds the air condition would get cold but on the freeway it would just stay cool . I figured this was the nature of the beast and just carried on.

I noticed smoke trailing behind me when just barely stepping on the pedal . So I proceeded to tune it........ the Italian way. After 3 to 4 good runs and enough smoke pouring out the back to block out all sunlight she simmered down.
No more smoke but other than the smoke I noticed the AC was freezing me out. It has stayed like that ever since . So cold it hurts on high fan.

This is not a bad thing especially living in south Texas !! Its just got me puzzled as to what could have happened

The wife has been babying it for a month while driving and before that it was in a deep sleep for about four years. "New" engine installed last month but the same AC the car originally had. It Still had a charge (R12 ) my mechanic checked it for her and topped it off.

Almost as if something broke free inside the system. Even the aux fan is kicking on and off now. Doesn't seem possible from just stepping on the throttle.

Any ideas ????


.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

sounds like you freed something up in the ac system... as far as the aux fan kicking in and out it probably coincides with the AC working properly now... before it probably wasn't reachinf the desired temp so it just stays on...

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

terminal velocity got the aux fan spinning!
it's a good bet that you need to replace or rebuild the aux fan.
that or the dead body finally dislodged itself from your condenser and the added airflow allows better cooling.

I agree. Either the blower is marginal or you cleaned out the condenser or evaporator at high speeds. Another option would be the A/C belt was slipping/some what off track and the fast speeds made it catch better.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

The aux fan worked when I bypassed it momentarily after the engine install but it wouldn't come on when the AC was on. Now it cycles on and off. I also washed the condenser while the radiator was out. As for the blower It will blow your hair back on high.

I'm not to familiar with the AC system I have a basic understanding learned back in the 80's but that's as far as it goes . Went to a trade school similar to wyotec .

Do the GM style compressors have vanes that may have freed up ? It would get cold then warm air would start coming out and continue to cycle like this the whole trip. Now it gets cold and stays that way. The aux fan is cycling on so the head pressure must be going up.

Its working now but summers coming so now is the time for the repairs if needed . 90 degrees as opposed to 100+

Thanks for the replies !

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

I guess anything is possible, but only thing I can think of is the aux pressure switch may have gotten shaken up real good from the spirited driving, and started bringing in the fan!
heck, I'm of the opinion that most anything can be fixed by a little hard driving!
NOT SUSPENSION OR STEERING ITEMS THOUGH!

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

The A/C gods have looked favorably on you.

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92 300D 2.5L OM602 OBK #59

For a little while at least .

Hopefully its not like a star which burns brightest right before it dies

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

Well Italian tune up had nothing to do with it. The fact that the A/C started working was just a coincidence.

Found out I have vacuum door issues. Fresh air door was staying opened then when it wants to it shuts resulting in cold air.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes