oil pressure question 300SD - PeachParts Mercedes-Benz Forum

Rooster300SD · #1 07-23-2009, 10:51 PM

I have a 1984 300SD. After I start he car should I always wait for the
pressure gauge to show pressure before putting the car in gear?
I never have, but the manual says to wait.

It always comes up to 3 bar right after I start moving.
Am I doing any real damage here?

Thanks,
Jeff

79Mercy · #2 07-23-2009, 10:55 PM

no, just don't rev the engine until the pressure comes up.

Shawn T. W. · #3 07-23-2009, 10:59 PM

I always wait the 2 seconds for it to come up . . . whats the big hurry? You just need to retrain yourself from that bad habit.

What if you "just took off" and then a mile down the road you notice it still hasn't come up yet, better to know, before you go . . .

Rooster300SD · #4 07-23-2009, 11:23 PM

I just started noticing it not going up right away
and I don't know how how long this has been going on.

After starting if I just sit in park it's taking 20-30 seconds to come up.
If I put it in gear it seems to come up more quickly.

If it takes a long time to come up is this a symptom of
some problem? After I get going it's always at 3 bar when
moving and at least 2 bar at idle.

Jeff

Shawn T. W. · #5 07-23-2009, 11:32 PM

Could be the gauge . . . or the line to it . . . or the pump is bled back down, and needs to be "primed" so to speak . . . (never heard of this . . .)

I would not atempt to drive the car until the gauge is showing presure . . .

What weight oil is in it . . .

Rooster300SD · #6 07-24-2009, 12:00 AM

Delo 400 15W 40

Diesel911 · #7 07-24-2009, 12:25 AM

Quote:

Originally Posted by Rooster300SD

I have a 1984 300SD. After I start he car should I always wait for the
pressure gauge to show pressure before putting the car in gear?
I never have, but the manual says to wait.

It always comes up to 3 bar right after I start moving.
Am I doing any real damage here?

Thanks,
Jeff

Did you recently change Viscosity or Brands of Oil?
How often do you do an Oil and Oil Filter change?

It could also be that the Oil Pressure Switch/Sending Unit is going bad.
I replaced on a gas car had stopped working completely and it also was leaking a little.

pawoSD · #8 07-24-2009, 12:39 AM

The transmission can't even engage that fast....give it a few seconds to circulate some oil!

Rooster300SD · #9 07-24-2009, 12:40 AM

I did an oil/filter change a few weeks ago.
Same brand & weight.

tangofox007 · #10 07-24-2009, 08:34 AM

In warmer weather, the oil pressure should come up almost instantly. Cold weather is another story. A slow rise in the summer could be the result of the oil in the filter housing draining into the crankcase due to tired seals on the filter lid pipe.

rrgrassi · #11 07-24-2009, 11:05 AM

The SD uses an elecrtical sending unit. It could be going out. Bleed back from the guage line is not a problem on this set up.

Diesel911 · #12 07-24-2009, 11:27 AM

Quote:

Originally Posted by Rooster300SD

I did an oil/filter change a few weeks ago.
Same brand & weight.

Sorry to respond with more Qustions. But, did you change the 2 little O-rings at the bottom of the Oil Filter Cap stem (#20 and #21 in the pic)?
If Oil goes by them it dumps back into the Oil pan.
There is also a Valve inside of the Stem that I assume could get stuck open (#19 Check Valve) if something got between it and where it seats. (On Member said he pulled some Cotton from the Bypass section of the filter out of his valve.)

macdoe · #13 02-08-2010, 01:05 AM

I have started having this problem after changing to ow-40 synthetic rotella.
why? what have I done? should mention that I did not change the filter, would that have anything to do with it? I think it has had almost ten seconds before the guage moves. I have a mechanical guage. I really don't like the feeling that the engine is about to seize. It has been very cold here so maybe that is why? I am worried.