W140 - 119 V8 (S500) oil pressure? - PeachParts Mercedes-Benz Forum

bourman · #1 08-27-2008, 12:03 PM

I have a 1998 S500 with 62K miles. I just noticed that the oil pressure has dropped off some from normal. Usually the pressure is at #3 on the gauge and maybe #2 at idle. Now it is at #2 below 45mph and #1 at idle. I'm running 10w30 Mobil 1 (can't find 10w40 anymore except for extended mileage).

What number does your S500 read at normal driving and idle (hot)?

Tks

deanyel · #2 08-27-2008, 12:38 PM

Your "usual" readings were about right. There's about a thousand bad sending units for every oil pressure problem, or maybe it's ten thousand. Try a search. The sending unit is at the base of the oil filter housing, cheap and easily replaced.

bourman · #3 08-28-2008, 01:06 PM

Thanks for the reply. I read a good article on oil tube replacement http://www.peachparts.com/Wikka/M119OilGuides that may be the problem. I guess the bottoms of the tubes can blow out under excessive pressure causing less oil pressure at idle. The symptoms are tappet noise, of which I do not have (yet). I also attribute some of the problem to the 10w30 Mobil 1 I'm running. I tried to find 10w40 or 15w40 Mobil 1, but all I could find was the 10w40 extended wear oil.

BOBB

JimF · #4 08-29-2008, 11:07 AM

Quote:

Originally Posted by bourman

I have a 1998 S500 with 62K miles. I just noticed that the oil pressure has dropped off some from normal. Usually the pressure is at #3 on the gauge and maybe #2 at idle.

Now it is at #2 below 45mph and #1 at idle. I'm running 10w30 Mobil 1 (can't find 10w40 anymore except for extended mileage).

What number does your S500 read at normal driving and idle (hot)?

I think that oil (10W30) is a bit "light" for your car.

I used 20W50 dino oil for years until about 6 months ago, I switched to 10W40 synth oil (Lubro Moly) and I immediately saw the oil pressure change; now it runs at #3 while in motion but after the engine is hot and idleing, the oil pressure as around 1-1/2 which is the min spec for oil pressure.

As deanyel wrote, the numbers sound about right.

deanyel · #5 08-29-2008, 11:50 AM

I guess thicker oil would be a good place to start. The problem with the oil tube hunch is that it's about 3 hours and $75 of gaskets to check it out, and you don't have the classic symptoms of the problem.

bourman · #6 08-29-2008, 12:12 PM

Quote:

Originally Posted by deanyel

I guess thicker oil would be a good place to start. The problem with the oil tube hunch is that it's about 3 hours and $75 of gaskets to check it out, and you don't have the classic symptoms of the problem.

I agree, until I start getting tappet noise, the oil tubes will have to wait! I may have to change oil brands to find 10w40 syn. Been running Mobil 1 for many years and hate to change, but maybe Castrol has a 10w40 syn I can use.
Thanks for the replies.

BOBB

bourman · #7 09-02-2008, 02:44 PM

Quote:

Originally Posted by bourman

Thanks for the reply. I read a good article on oil tube replacement http://www.peachparts.com/Wikka/M119OilGuides that may be the problem. I guess the bottoms of the tubes can blow out under excessive pressure causing less oil pressure at idle. The symptoms are tappet noise, of which I do not have (yet). I also attribute some of the problem to the 10w30 Mobil 1 I'm running. I tried to find 10w40 or 15w40 Mobil 1, but all I could find was the 10w40 extended wear oil.

BOBB

Check out this URL: http://www.whnet.com/4x4/oil.html
Looks like Mobil 1 0w40 or 5w40 is now the right oil for the 119.

deanyel · #8 09-02-2008, 03:33 PM

119 motors are fine with whatever you put in them. It's those sissy next generation engines that require synthetic.

JimF · #9 09-02-2008, 08:07 PM

Quote:

Originally Posted by deanyel

119 motors are fine with whatever you put in them.

Spoken like a man who knows his 119 engine!

I've got to 'fess that my 119 does run better . . . much better . . with synth. I've always used dino oil (20W50) but about 6 months ago, my tech talked me into 10W40 Lubro Moly.

As I drove out of his shop onto the hiway, I could feel the difference. . . no bs! The car runs cooler and, to boot, I'm getting better gas mileage (even w/o the acetone).

That's made a believer out of me for synthetic oil.

deanyel · #10 09-02-2008, 10:22 PM

I'm still stuck on conventional - partly because I've stockpiled it, but also because I've had a couple of engines, a 103 and a 119, leak with synthetic, and stop when it was taken out. But with gas prices what they are, and the declining oil price gap it does seem like the argument gets stronger all the time.

JimF · #11 09-03-2008, 11:04 AM

Quote:

Originally Posted by bourman

Check out this URL: http://www.whnet.com/4x4/oil.html
Looks like Mobil 1 0w40 or 5w40 is now the right oil for the 119.

I made a 'report' from the html using Word. Nice summary for the printer.

Peter Guenther · #12 09-03-2008, 11:47 AM

I switched to synth, on the advice of my service mgr at MB, about 3 years ago, no issues. The 119 engine idles with very low oil pressure, but jumps up with a slight increse in engine speed. They show a graph in the "intro to service" or "service bulletins". The dealer uses 15/40 synth Mobil one, $6 vs 3.50 for conventional.

RConrad · #13 09-06-2008, 12:15 PM

I have a 96 S-320 thats been on Mobile 1, 10w30 since new. At about 70K, I noticed the same problem, had it checked and was told it meets the min. for pressure. I tried 15W50 with little change, so now I take it out out gear at stop lights and at idle it reads about 2 to 2.5. I'am now at 103,000 miles with no problems i know of(nock-nock). Hope this helps.

Ron