After my oil change, and I also changed the o-rings on the stem of the filter housing cover, at idle I only get to about 1 bar and when hot, it gets to about 1/2 bar.

Running Mann filter and Delvac 15-40

I've run out of the easy fixes............ ideas???

JCD

I don't see the correlation between the o-rings and the oil pressure. If it were bypassing the o-rings it just doesn't get filtered, right? There shouldn't be that much pressure drop if no flow through the filter which you should have done the opposite.

Do you mean 1.5bar driving? I don't know if I'd care to drive on that little of pressure, seems like it'd eat up the turbo pretty quickly. Are you certain it has enough oil in it? Does the oil seem normal? I've heard of pennzoil getting putting the wrong oil in the wrong bottle a while back, could they have put the wrong oil in the container?

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Oil level is correct, oil pressure pegs as soon as I get on the accelerator. I changed the oil.

My issue is only at idle.

You still should be safe at idle with that pressure although most register a lot higher. I wonder if there is a problem with your guage?

__________________
1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Also, ensure your RPM is set properly. I know that a 50 RPM difference higher will yield about .3 bar higher pressure.
Have fun,
Adam

Kept an eye on it on the way home.

Pretty much stays pegged until the engine comes up to operating temp.

Then will drop to 1 bar at a slow roll, i.e. in stop and go NJ traffic, then if I stop it drops to just about O psi. Put it in neutral, it goes up to 1 bar.

At idle, RPM does cycle a little bit. I have the idle adjustment turned full bore.

Bummer,

JCD

JCD,

If you're up for an experiment... take off your oil filter cover, wipe down the rod and o-rings. Maybe move the O-rings around a bit to insure they are not compressed and leaking. Replace the cover and see if the pressure is back. I'm halfway there in the experiment.

A couple of months ago my car had dropped pressure at idle, just like yours. I replaced one of the o-rings and life is good ( the dealer only had 1 the first time around). Lots of local / commute driving but no long trips. I take a 400 mile drive one day and at the end the pressure drops at idle. I take off the cover, clean and that time I replaced the second o-ring. The pressure is back and stays high for another 2000 miles of local driving / commuting.

Last week-end I go on another 400 mile drive. At the end of the day, the pressure is low again. It stayed low at idle today also. I pulled the cover and cleaned the o-rings again. Unfortunately I also pulled a leaking injector hose. I was hoping to clip the end and reseat, but the hose was so rotten I need to get a new one. Can't get a diesel fuel line here in NASCAR city after 5 - probably can get a 9000 rpm forged small block crank on every corner. So I can't restart to test until I get more hose tomorrow. I'll let you know what happens.

Anybody have any other suggestions on what it might be? Seems the person in the other thread replaced a bypass valve?

Chuck

I had an M103 like that. I replaced the main and rod bearings. That did the job.

Spec I believe is 0.4 bar minimum.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Chuck,

I did what you suggested this past weekend.

Issue is still there, but only after it has been run hard and the engine is up to temperature.

JCD

jcd, there are 2 pin holes in the oil filter stem, one near each end. when i changed my o-rings recently i noticed these pin holes were clogged with debris. blew 'em out with compressed air.
not sure if this would help you but may be worth a try.

__________________
1984 300D Turbo - 231k....totalled 11/30/07 RIP

Forgot about the pin holes.........................................

I'll check it tonite.......... keep fingers crossed.

JCD

You might need to ream that hole...and it is pretty small... and the backed oil in there may be hard......if you have safety wire and one of those nifty automatic safety wire twisters you can make one really easy...that is tough wire...

Last time I did it I just used a safety pin. That'l be my first attempt.

JCD

Isn't the inside of the tube hollow......and supposed to stay that way.... like 8 or 10 inches long hole ?

I experienced a similar oil pressure problem shortly after changing the oil on a '79 240D I once owned. The cause was debris in the oil pressure relief valve. The debris was the remains of a slowly disintegrating vacuum pump.

When the shavings were removed from the valve, it operated properly and the oil pressure returned to normal. There remained a mystery, however, which was the presence of a dozen or two small ball bearings in the sump screen.

The mystery was solved when the vacuum pump failed totally some months later. Though I should have, I never did removed the oil pan a second time to recover the rest of the vacuum pump.


Phil

'84 Euro 300D
'85 300D