no oil pressure again 400e
 

hey guys.
when i drive my 92 400 e...92000 miles...hard and fast i loose oil pressure...but when i look in the oil fill cap the oil is flowing strong. any input??

What does it show when you check the dip stick? Have you checked the sending unit against a manual pressure gauge?

The dipstick is full and I think your idea about the sender perhaps being at fault is a good start. Can you tell me where it is on this model. Thanks

Brian

Can you describe this in more detail?

What is the pressure at cold startup, at cruise while cold, at cruise and hot, and at idle and hot?

My car has a mechanical gauge with an oil line so I'm not sure where your sending unit is. I would expect somehwere in the area of the filter housing. Any 300E owners able to confirm the location?

pegged at start up cold same same at cruise cold..cool

at warm anywhere from 10 to 30.. same same hot with intermitent flickers that
drop it to zero sometimes. Idles at or near zero then i give it some gas and it rises...then it wont..

That's probably what I didn't want to hear. It is the same that I experienced and the reason I am regrinding and polishing my crankshaft.:mad: It sounds as if you are losing pressure as the oil heats up and it runs out the worn main and rod bearings. My oil pressure was great when cold. But when hot, at idle it would hover at about 1/2 bar (7 psi) and sometimes go to zero. Give it a little gas (maybe 200 more rpm) and the pressure would go up to 1 bar (14.7 psi) or more.

I drove my car 8 months or more like this. I would always keep the rpms up at idle to make sure I always had sufficient oil pressure. A broken timing chain is forcing me to do a complete overhaul. I'm not sure if the two are related.:confused:

The MB spec I guess, is a minimum of .7 bar (10.3 psi) pressure.

Thanks for the reply. Let me share an observation ot two. When I accelerate the pressure goes to normal but will sometimes drop during the acceleration curve erratically. I'm still leaning towards a bad sender but will read more on the lead you've given me.
Thanks again for the input and I'll post updates. By the way the car has only 92,000 miles. Shouldn't have the wear you've alerted me to. I've got my fingers crossed.

Bzoo,

FWIW, I drove a '94 E420 to 300,000 miles and had to replace the oil pressure sending unit 3 times. The first time it did it, it scared the... well, I was SHOOK!

I was driving down the interstate and noticed that the gauge wasn't pegged. Ten miles later it was almost on zero after jumping around erratically. A local independant mechanic actually made a fitting adapter with a tap and die set so that he could hook up a manual guage and confirm good oil pressure. I drove the 100 miles home and had the sender replaced the next day.

A varient of this scene happened twice more (without the panic) while I owned the car. Iwould suggest, however, that you address this ASAP. If it is not the sending unit, continuing to drive the car can only add to the problem.

Best Regards,

Steve

Sorry, I didn't see the erratic part. That certainly could be the sending unit. I just bought a new one by VDO for $56. Thought that since I was rebuilding, I should replace it.

thanks for the info..I tried to find the sendor last night with no luck. going to try a search today I guess to see if there is a picture on line..

If memory serves, mine was on the back of the filter housing.