oil pressure on my (potential) 300sd - PeachParts Mercedes-Benz Forum

wheelguru · #1 07-29-2003, 12:10 PM

I have been looking at an '81 300sd, 165,000 miles. compared to by '78 300d it is a dream, once I get over my preference for the 123 body style.
I used the search and couldn't find much that seemed to pertain to this car, Do these have electric instead of mechanical pressure guages?
I have a concern about the oil pressure . Does not seem like it is anywhere near what it is on my 300d. it reads 1.5 at idle with the car warming up, and nudging the accelerator does not kick it right up to 3, only to just over 2. After it warmed up ( a few miles on the interstate at 70mph) it idles at stoplights at just under 1 and glides serenely up to 3 when I start to move. It is at 3 at about 15mph.
Am I obsessing or should I take a pass?
He wants $3500, and will get the AC and bad motor mount fixed before I buy it.

SHARK1007 · #2 07-29-2003, 12:31 PM

My recollection is that you want 3 bar at 1200 rpm or so, much lower at idle.

Have a pre purchase inspection done b an independent, get a litle peace of mind.

#3 07-29-2003, 12:40 PM

I don't think that the readings you are getting are particularly bad although they are slightly lower than what I would consider normal. My 300SD idles halfway between 2 and 3. Under any accelleration at all it pegs out at 3. I would ask when the oil was last changed. From what I've experienced, as the oil ages the oil pressure readings I see at idle tend to decline ever so slightly. It might be time for an oil change. Also, what weight of oil does the owner say is in the car? Is it diesel rated? These might affect the reading. If they don't know that might be a bad sign. You might also want to pull the lid off the oil filter housing and look at the two o-rings on the end of the stem. If they are missing or dried out then that can also affect the oil pressure readings. Also, idle speed settings will affect the oil pressure you see at idle. This, as much as anything, probably accounts for much of the variation in we all report our readings to be. Does it seem to have a low idle speed?

P.E.Haiges · #4 07-29-2003, 01:30 PM

Wheel,

I have found that 3 BAR (45PSI) is at 1400 RPM on 3 MB300SD I have. All have mileage over 200,000 miles.

P E H

wheelguru · #5 07-29-2003, 01:49 PM

THanks for the replies. The tach only works intermintently on this car, but I am sure it takes more than 1400 to peg the gauge, even when it is not fully warmed up. Much as I like it, I think I will keep looking, smaller repairs don't scare me at all, but I want one where the motor will go 75 to 100,000 more miles after I get the car. -Andy
anyone know of a good one for sale?

JPL · #6 07-29-2003, 04:27 PM

hi

yea, when i accelerate in my 35 300SD the preasure meter is pegged.

I'm with ya on the preference for the 123 body style. I still miss my 300CD dearly. Both body styles have thier own set of pluses and minuses, but I always felt the 123 was more stylish.

just my 2 cents

P.E.Haiges · #7 07-30-2003, 01:26 AM

Sorry guys, but I think the 123 looks cheap. The 116 is the best looking MB looking ever in my opinion. Especially with the euro headlights.

I'll probably get the old saying about opinions.

P E H

Stevo · #8 07-30-2003, 02:41 AM

PEH

I love my 123s but I gota agree with you on the 116s. They have to be one of the classiest old MB ever put on the road. If I could only get one with a manual tranny.

240Demon · #9 07-31-2003, 04:16 PM

Watch what you say about 123's...how the hell do they look cheap??? I think the 116 is one of the ugliest cars MB ever made!!