w140 oil pressure - PeachParts Mercedes-Benz Forum

Victor300E · #1 11-24-2005, 04:32 PM

Hello
What are your oil pressure readings on w140 v8? car is 92 500sel. Just changed oil pressure sensor and gauge shows between 0 more toward 1 on idle on 85degree engine and never rises above 2. When I start car in morning sounds like engine knocks for like 15 seconds then pressure rises to 3 and knocking stops.
Thanks for input

duxthe1 · #2 11-26-2005, 01:39 AM

Sounds like you need to get that to a shop, now! Your oil filter housing check valve is sticking. This in turn has caused your timing chain to slap against it's plastic rails after cold starts and break them. Those broken plastic pieces in turn are clogging the intake screen of your oil pump, causing the low pressure. If you don't have that addressed asap it will cost you your engine. There's one on the lot at my shop now with a broken #6 connecting rod caused by the same scenario!!!

Hatterasguy · #3 11-26-2005, 06:14 PM

The knocking bothers me. I wouldn't run the car until you can get a mechanical guage on it to confirm that you have good oil pressure.

Afaik MB specs .3 bar at hot idle. The guage should also peg at 3 bar by 3k rpm.

But the average on healthy engines seems to be between 1.5-2 at hot idle pegging at 3 by 1k rpm.

Remember the M119 is an extremly expensive engine to do any internal work on.

Victor300E · #4 11-27-2005, 04:01 PM

thanks for replys guys. I changed oil (0w40)and filter and new oil pressure sensor. filter looked defformed and full with little particles like metal and plastic. i bought this car because it had broken timing chain guides and broked distributor cap. chain skiped 2 teeth on intake camshaft sproket. i installed new upper and inner side guides, reset timing. didnt checked compression yet but engine sounds very healthy(no bent valves) ecxept knocking in mornings. so after oil change, thank god, oil pressure is up to 2 on hot idle and goes to 3 when engine at 3k rpm. can i change that sticking valve myself? also how hard it is to remove oil pan? i heard you have to lift the engine or something?
thank you for help
victor

Hatterasguy · #5 11-27-2005, 07:32 PM

Pull the valve covers and change the little oil bridges. The caps blow off the ends of them and will cause a lifter like noise.

deanyel · #6 11-27-2005, 10:30 PM

Quote:

Originally Posted by Victor300E

can i change that sticking valve myself? also how hard it is to remove oil pan? i heard you have to lift the engine or something?
thank you for help
victor

I don't know if your oil filter check valve is sticking but it's probably not a bad idea to change it, not too hard and not too expensive. No need to take off the pan though, just the oil filter housing, 3 allen head bolts. You'll need the check valve kit and an oil filter housing gasket. Of course you've got to drain the oil first.

86560SEL · #7 12-29-2005, 12:55 AM

Just did a search and found this thread. I am a bit confused about my oil pressure. As you may have read on my other topic, (getting little/no response).

I have been concerned about my oil pressure gauge readings. I changed the oil after I got the car, the oil was very dirty and the filter was shot and literally had a big hole in the side of it. I put in new oil and a new oil filter and initially, the readings seemed to be the same, if not slightly better- which seems normal. I have been reading that it (gauge) should be at "3" bar by 3000 rpms, but mine is at the "3" bar at about 1700 rpms and it at about "2.8" bar at 1500 rpms when the engine is around 85*C. My concern is when it is at idle, in gear, when the temperature is above 80*C. Today, it was nearly at "0" when it was idling in gear when the engine was hot. When I placed it in park it went to about .3 bar. Before it seemed to me like the pressure was better before I changed the old oil out. I may be wrong. I checked the oil level and it is fine. I also used 15W-40 as recommended by the owners manual. I did use a "purolator" oil filter however. Could this be the problem, or is my engine worn out? Should I put in an additive? Should I go with a thicker oil and a MB filter?

It is a 3.8L V8, with 264K. It still does not smoke, or burn oil, so I guess that is a plus.

Thanks for any advice.

rsmcmahon · #8 12-29-2005, 03:07 PM

Victor,

The 92 500SEL has metal oiler tubes that are not subject to failure as in later years when MB use the plastic oiler tubes. Since you mentioned the car has suffered a failed or broken guide rail, have you removed the oil pan? The reason I mention removing the oil pan is because the broken fragments of the rail will lodge in the oil pickup screen which can alter the engine’s ability to deliver oil.

Take a look at the following TSB’s too regarding engine rattle on startup.