Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
220 D "1970"
Joined
·
43 Posts
Discussion Starter #1
In the process of fixing up me ride,evidently I brushed against a few wires.
My temperature guage stopped working & the oil guage now wants to read full pressure (It does fall back just a little) but far from correct.
So,I read my manual,It tells me there is a "Oil pressure relief valve"......anyone have any expierence with this?
They say It is located on the oil filter.
I bet this would at least solve my oil guage problem.

All help appreciated
 

·
Registered
E320 wagon
Joined
·
953 Posts
Most engines have a fixed spring and washers /shims to get the correct spring pressure = oil pressure. Other engines have a screw adjustment setting ,normally Clock wise to increase. On high mileage engines higher than normal pressure sounds odd. Maybe your gauge or sensor - sender is bad , do the cheapest fix first . If your crafty check the wires and plug as it could be just a bad crimp or pin in a plug



28 yrs aircraft mech.
 

·
Registered
85 300GD 83 300TD
Joined
·
978 Posts
The 220D has a mechanical oil pressure sender and gauge. It reads full pressure always when running and will drop to 2 bar or so at idle when hot. This is normal. If it does not reach full pressure there is a problem and I have had two MB diesels with failed pressure relief valves as the cause. This again is a low pressure problem and a rare occurance.

-Dai
 

·
Registered
220 D "1970"
Joined
·
43 Posts
Discussion Starter #5
Well,The guage used to read fine at 30 on startup,at least I thought this was a good pressure?
When it caught my eye as maybe malfunctioning...It would register 45,and then barely back off if any at all.
I even drained a little of the oil thinking that I might have overfilled It a bit.
So,this standard guage reads as follows (0,15,30,45)
It should be at the high pressure end all the time (45)?
I thought it should fluctuate more as the RPM's were increased.
I'm a newbie owner so all wisdom is much appreciated.
 

·
Registered
Joined
·
499 Posts
That the thing I like to see in any merc i drive,the oil guage "pegged".It's supposed to be like that.It sounds like the releif valve was stuck open before and now it has returned to normal.
As it says in the mercedes engine manuals,if in doubt,set up a auxillary guage connected to the engie and check the pressure.You only need to do this when you have LOW reading.So stop worrying, be HAPPY![:D][:D][:D]
 

·
Registered
Joined
·
35 Posts
Hey There,
I also noticed a 'pegged' oil pressure reading while running and then having it drop to 30 or so at idle (stoplights). Since this is normal for a 220D how about a 280SE FI 6? Hopefully it's nothing to worry about but I'm also new to the Benz ownership club. I bought it this afternoon.

Thanks,
Scott
"Helga" (The cars personal name since the 1st owner)
1970 280SE Sedan
 

·
Registered
91 350SDL; 84 300d; 71 220D; 68 280S; 93 300d (2); 86 420SEL; 83 280SL (grey); 83 240D;
Joined
·
37 Posts
The temp gauge is also mechanical. when ign is on it sends pwr to gauge to activate pointer.
 

·
Registered
1972 Mercedes 220d
Joined
·
1 Posts
Location

Did you ever find the location of the relief valve?
I'm reading 45 the minute I turn the key to the on position and remains there regardless if idling, rpm, or operating temperature so I assume the line is clogged.
I have purchased the valve but have no idea where it is located on the w115, 220d. I figure it's in one of two locations, somewhere next to the oil filter housing base, or attached to the oil pump inside the pan.
Currently I can see oil being sprayed onto the camshaft so I assume everything is kosher but would rather be safe than sorry. Any help would be appreciated.
Eric
 

·
Premium Member
1973 220D, 1988 300SEL, 1991 300TE
Joined
·
330 Posts
On my 1973 220D - the owners manual recommends 20w50 or 10w40 motor oil. If I use 20 50 the oil pressure gage will be pegged at 45. If I use 10 40 the oil pressure will also peg at 45 unless the engine got hotter than usual (climb a big hill on a hot day) and then it will fall back a little to 40 or so at idle.

So your car sounds normal. The temp gage might have come disconnected - it is not electric it is just a thermal mechanical gage.

The engine should run at 185 or just over the 175 mark and it should not go above the next mark. Even in winter, going downhill, the engine temp should hover around the 175 mark. If it keeps going too high check you radiator flow and if it keeps going low check (change) your thermostat.

Good luck,



Sent from AutoGuide.com App
 

·
Registered
1972 220 D, 1974 450SL, 1995 E300D 2002 S430, 1976 300D, 1986 SDL, 1982 SD
Joined
·
2,708 Posts
All the Mercedes cars are engineered to run at oil pressures above 2 bar (30psi). The standard is to have the thing pegged at a full 3 bar (45psi). In more recent cars, the oil pressure gauge has been deleted, since too many owners got confused about proper pressure.

SO-- Low pressure BAD, pegged pressure GOOD!

Low pressure is an indication that there is a lack of oil.
 

·
Premium Member
1973 220D, 1988 300SEL, 1991 300TE
Joined
·
330 Posts
Well starting in '76 with the w123 the oil pressure in a warm engine will fall to 15 or so with the ending at idle but rise up to the peg as soon as you raise the RPM.

But your engine is normal to be pegged pretty much always.


Sent from AutoGuide.com App
 
1 - 13 of 13 Posts
Top