Even though I have been a MB owner for over
18 years, I recently found your site: GREAT!
I have a 1984 300SD and a 1963 190SL.
SD Questions:
1. What should the oil pressure be after
traveling on a long trip on the inter-
state going 75 mph. (car has 221,000
miles). Really, want to know what would
be normal with this mileage.
2. This year when I turn on the air
conditioner, the car will idle great
for maybe 5 seconds, then it will begin
to idle rough. Other times, it will
idle rough all the time with the air on.
Previous years, idle was the same with
or w/o air. Car idles as a gasoline
car with air OFF. Cools great!
190SL Question:
Car has webers with the "pancake"filters.
Will installing the original silencer
make the car sound much less nosiy?

I realize this a long post. Answer only if
time permits.....THANKS!!

1) the weight of oil you use will affect the oil pressure when warm, I would expect that the oil pressure at idle, in gear, and warm after driving 75 miles would be 1-2bar or 15-30psi range with 20w50 oil in the engine.

2) The rough idle problem could be weak motor mounts(causing you to feel more of the engine vibrations), Loose A/C belt vibrating (have heard them where it felt like the car is comming apart), or possibly an idle rack limiter that the spring is weak which allows the injection pump rack to oscillate too far causing a "rocking" affect in the whole car.

Re: 190SL
That car was made before I was concieved, and I have only had the opportunity to work on one (brakes). Sorry can't help.

------------------
MB Medic
14 year MB tech
7 year shop foreman @ independent MB/Volvo shop

Weber carbs are going to be somewhat noisy unless you construct a box to pull the air from outside the engine area.

------------------
MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH