Question for anyone in the forum.

[lsmalley]

I have a 1990 190E 2.6 and I recently removed the valve cover and cleaned it as well as the gasket. My gasket is probably the original and I ordered one so I could replace it as I have an oil leak (that was minor, but is now not so minor since my recent removal of it.) Anyways, my oil pressure was fine for a few days after, but today I noticed that the oil pressure is really low i.e., at 0 on idle in "Drive" and also at 0 at idle in "Neutral." It used to read between 1 and 2 bars at idle on "Neutral" and 0.X to 1 at idle in "Drive." Is this because of my excessive oil leak because of my badly deteriorated valve cover gasket? I read several other threads on here from members with similar cars as well as other model MBZ's and they mostly all had something to do with the oil sender unit, however no one had ever mentioned to have excessive leakage from their engine which causes me to believe that my circumstances are a little different.

[compress ignite]

'Could be ...
IF YOU'VE LET MOST OF YOUR OIL LEAK AWAY WITHOUT REPLACING IT!

More likely the two rubber o-rings on the Oil Filter cap shaft are old,hard and brittle.

OR your Bearings are GONE and don't hold pressure anymore.

Most Likely ,However, is that you've knocked loose the OP sensor line [Wire].

[lsmalley]

I recently cleaned my engine compartment with Easy-Off (works great and fast!) and I can see that there is now oil from the area around the gasket on rear of the crankshaft by passenger side as well as some oil a little closer towards the front of the crankshaft, but not all the way at the front. My new gasket will come in probably tomorrow so I will see if changing it will solve the low pressure problem. Almost forgot to mention that when I was putting the valve cover back on I snapped off 2 of the eight bolts that hold it together. Any relevence with the low oil pressure?

[junqueyardjim]

Slow down a bit and think this through. Yes your gasket has to do with oil pressure only if you let all your engine oil run out. If you have enough oil to read it on the dipstick, you could be very low on oil, but should still have oil pressure. What with all your messing around you probably knocked off the wire from your engine oil sender switch.. That happens when you clean an engine real good. Gaskets can leak, bolts or screws can get broken, but if you have oil in the engine, you probably have oil pressure when the engine is running. Make sure that you have oil in the engine. If you don't have oil presssure, you engine will sound awful in just a minute or two. Make sure your oil pressure sender has a wire connected to it.

[lsmalley]

Ok, so I am a noob when it comes to finding out things on my own, where is the engine oil sender located in respect to the valve cover gasket? Thank you all for your input in this

[Ivanerrol]

The oil pressure switch is actually under the manifold and under the cruise control actuator. You need to get at it from underneath the car. Cleaning engines is a two edged sword.

Get those broken bolts out. Make sure the new valve cover gasket is on properly and the the cover tightened down to correct torque specs.

[lsmalley]

Ok so I just went back out and looked under the hood to examine the area that I was working around and found that a vacuum line that connects to a black tube that goes on top of the air filter housing and attaches to the valve cover was broken. I put a new piece of tubing on to rectify that issue. I then continued looking around for anything else that may have been disconnected around the immediate area, but found nothing. I next attempted to locate the oil sender unit which I think I found from under the hood. It is a plug that attaches to the rear of the oil filter housing correct? If that was it, it was connected properly and infact it was so far down, that, that was one of the parts that I didn't tamper with when cleaning the engine....I actually covered a few key electrical components that I could see as well as the abs unit and belt and used the Easy-Off around the perimeter of the valve cover and also certain areas that collected gunk like the p/s reservoir etc. I then hosed it off with a medium pressure spray making sure not to let any water get into the spark plugs..... Anyways, I took the car for a test drive a about half an hour ago and the oil pressure seems to be operating as it was before. I drove around for about 45 mins to make sure the engine was at its normal operating temp and it seems fine now. At 2000 rpm it is at 3 bars again, but before I would have to add a little more gas to get it to go up to 3 bars. We'll see how it goes tomorrow. Thank you all for your input I will keep you updated. And yes Ivan, I need to get the bolts out, not sure if I can do it by myself because I fear making a bigger eff up than I already did, so once I get my new parts in I will call my mechanic and see if he can get them out for me.

Thanks again,

- the Noob

[Cal Learner]

Originally Posted by lsmalley

Ok so I just went back out and looked under the hood to examine the area that I was working around and found that a vacuum line that connects to a black tube that goes on top of the air filter housing and attaches to the valve cover was broken. I put a new piece of tubing on to rectify that issue....

That line runs from the shaped breather hose down to the fuel pressure regulator, and allows raw fuel back into the engine if the diaphragm in the pressure regulator is torn.

Originally Posted by lsmalley

I next attempted to locate the oil sender unit which I think I found from under the hood. It is a plug that attaches to the rear of the oil filter housing correct?

Yes, that is the sender unit for the oil pressure gauge in the instrument cluster. There is also a sender unit for oil level, fitted into the driver's (left) side of the oil pan.