hello,
my 87 300 sdl's (268k) a/c runs intermittedly. sometimes it performs like an igloo and other times just blows warm air.
the temp today was 101f on the dashboard thermo.
any ideas on why this is?
also glow plug light comes on only intermittedly as well.
it's been a little difficult to start lately.
she smokes a lot when first started.
any input/suggestions are greatly appreciated.
thanks.
daniel

I had the same problem with my AC about a year ago. The problem was the pressure and temperature switches located near the AC dryer (behind the left headlight). Regarding the outside temperature gauge, mine has never worked properly and is always inaccurate, so I just live with it.

For the AC problem, read this:

86SDL A/C Question

For the outside temp gauge, mine reads 136F most of the time. Might dip to 128 in the winter.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Check the condition of the serpentine belt -- if it is in poor condition, it can slip at some temps, so the AC will cut off, stays off until you restart the car. Very common, and I'm going to check mine to make sure it's not sliding (poor AC performance, I dont' really want to covert another one....)

The hard start and smoke is a result of a bad glow plug or two, replace them. If the light doesn't come on, but blinks after you start, or blinks instead of staying on constantly, you have at least one bad GP. It won't go on at all with more than two bad.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Low,

Do a resistance test on the GP. If you are lucky and one or two GP are NG and have to be replaced, they will be the ones that aren't too hard to get at. If either of the center two have to be replaced, you might invest in some extra socket wrench extensions and swivel joints.

P E H