W115 oil pressure question - PeachParts Mercedes-Benz Forum

JordaanDMC-12 · #1 11-19-2009, 01:16 PM

Quick question about oil pressure on my 70 220D

I was picking my sister up in Santa Clarita about 150+ miles away and my oil level was halfway on the dipstick and while I was driving on the freeway my oil pressure was up and all was well but as I saw traffic ahead I put in the clutch to brake and my my oil pressure guage dropped to the zero. A bit suprised I pushed the accelerator to make the pressure rise and then as traffic became stop and go my oil pressure went back up at idle to the middle.

I noticed that if I drive for long periods of time at higher speeds and then decelerate the oil pressure will drop really low almost touching the zero, but if I give the car time to settle it'll be normal and be halfway..

Is this normal?

79Mercy · #2 11-19-2009, 04:36 PM

Its normal for the oil to drop down a good bit after driving fast but not all the way to nothing. The manual says .3 Bar at idle and 3 bar by 3000 RPM(in my opinoin that is not enough). Both of my cars will never drop below 1 bar or 15 PSI after driving at highspeeds for a long time but peg at the top when I speed up.

What kind of oil are you using?

strelnik · #3 11-19-2009, 08:04 PM

Quote:

Originally Posted by 79Mercy

Its normal for the oil to drop down a good bit after driving fast but not all the way to nothing. The manual says .3 Bar at idle and 3 bar by 3000 RPM(in my opinoin that is not enough). Both of my cars will never drop below 1 bar or 15 PSI after driving at highspeeds for a long time but peg at the top when I speed up.

What kind of oil are you using?

Oil viscosity and frequency of change have a lot to do with this.

Ian White · #4 11-19-2009, 08:06 PM

Run 20w-50 then you'll have oil pressure!

79Mercy · #5 11-19-2009, 08:11 PM

Quote:

Originally Posted by Ian White

Run 20w-50 then you'll have oil pressure!

You might get oil pressure but you wont get the added soot control and zinc because there isn't a diesel rated 20W-50.

Ian White · #6 11-19-2009, 08:18 PM

Quote:

Originally Posted by 79Mercy

You might get oil pressure but you wont get the added soot control and zinc because there isn't a diesel rated 20W-50.

Actually a european company has something... Check it out:

http://www.eneos.eu/product/pdf/PB-ENEOS-20W50.pdf

79Mercy · #7 11-19-2009, 08:28 PM

thats the first 20W-50 diesel oil I have seen.

Ian White · #8 11-19-2009, 08:32 PM

Quote:

Originally Posted by 79Mercy

thats the first 20W-50 diesel oil I have seen.

Me too

Skippy · #9 11-19-2009, 10:19 PM

.3 bar (about 5 psi) at idle is ok, but normal is much higher. Both of my diesels will get down to about 1.5 bar after they get good and warm. What kind/grade of oil are you running?

JordaanDMC-12 · #10 11-19-2009, 10:33 PM

I'm using Castrol GTX Diesel SAE 15w-40

It's the most inexpensive at autozone.... Is this the problem?

I'd love to use 20w-50... anything that might last longer! I forgot to mention that when I started the trip I checked the dipstick and it was halfway but I got back from the trip and it's at the min line! again!

I have pretty bad blow by but damn, I'm loosing more than half a quart of oil in a 180-200 miles trip?! what the hell??? That much oil comes out from my blow by on top?

I used to get only Delo but they don't sell quarts just the jugs and they're pretty expensive...

Skippy · #11 11-19-2009, 10:37 PM

The oil sounds like a decent enough choice. Are you sure your oil isn't just leaking out, maybe from the cooler or cooler lines?

JordaanDMC-12 · #12 11-19-2009, 10:47 PM

Quote:

Originally Posted by Skippy

The oil sounds like a decent enough choice. Are you sure your oil isn't just leaking out, maybe from the cooler or cooler lines?

Good to hear I'm not using the worst oil lol I was afraid of that. As far as I can tell I'm not leaking from anywhere else but the oil filler cap and the tube that comes out of the valve cover (don't know what's called) It leaks bad out of there but I can't see more than a quart coming out of there.

I'm going to degrease the engine tomorrow and see if it leaks from anywhere else. I just replaced the bottom oil cooler line and the top one is dry. And I know for a fact the bottom one is tight!