94 E320 W124 No Oil Pressure at idle
 

Last night noticed oil pressure was 0 when stopped, but just revving the engine and normal driving its 3 bars.

Pulled over, looked underneath and there is a hose loop hanging down in the rear engine or transmission area aft of the engine tray/cover.

Engine runs/idles perfect. I've been plagued with this (see my last thread - M104 Rear Main Seal leak? )

Very discouraged, because I got this car for its reliability and safety. I'm retired vet and going on my 3rd year of unemployment sans a couple of consulting gigs, so we're broke. I'm HORRIFIED this is going to be expensive. This is our ONLY transportation, as my Truck rear end went out 2 weeks ago.

Sorry for the whining : (

Plan to ramp/jack it up and get under it today or tomorrow to see what there is to see, but as my last post states with oil problems like this I feel like these repairs are out of my league. I am willing to try and pull the transmission to inspect the rear main and front trans pump seals.

Is my Oil pump going bad also?

With only 168,000 miles I didn't think these kind if issues would happen.

1994 E320 W124/104 with 168,000 miles. Head Gasket and Wiring Harness replaced by last owner. Purchased at 145,000 miles, car had 80% complete maint records. Keep oil/filter changed. Last nights temp was 31F. Live in the greater Atlanta area (Dawsonville). Running 5W30 oil.

The chances of a real oil pressure problem are virtually nil. You have either a oil pressure sender problem or a lower engine wiring harness problem. The next step is to inspect the wiring that goes to the sending unit. If it's bad, i.e. crumbling and bare, you need to either replace or rebuild the harness. If the harness looks good just replace the sending unit, not very expensive and easy to replace.

PS - the sending unit is at the base of the oil filter housing.

I had the same problem a few years back and it was the oil pressure sender. It was easy and inexpensive to replace. Deanyel is right about the harness to the oil pressure sender...the insulation was flaking and crumbling...about 2 inches of the wire leading up to the sender crumbled as I took it off. Used electrical tape and silicon spray to "fix" the harness. It's been about three years and it's still ok.

Possibly not a problem
 

My 1995 E320 wagon has shown no oil pressure for two years. The gauge reads normally when cold, but 5-10 minutes later, I get zero at idle, and 2.5 to 3 above 1500 prm.
If you let it sit and idle for 5 minutes you would expect a lot of niose, at least lifter noise. not the case.
Most likely it is the sender unit. The shop told me the sender is a ***** to get at, so I decided to foregt about it. Two years later, with 191k on this car, it runs great. I suppose this will be an issue when I sell the car.
Until then, Don't Worry; Be Happy.

Hey Paul, I have a 1995 e320 wagon too..and the oil pressure sender unit was easy to replace and was easy to get at once the car is on lifts. If it wasn't inexpensive or easy to replace...I just would've lived with it like you:)

It doesn't need to be on a lift, you just have to be able to get underneath it.

OK, up on ramps, inspected. Oil coming out from sender, but LOTS of oil running down transmission bell housing drivers side, plus coolant drops both sides of bell housing.

I reinspected upper engine and I believe I was wrong that the head gasket was replaced. I only see evidence the timing belt covers etc were worked on (rtv on seals). Car had front end damage from previous owner, I bet that if they replaced radiator/hood/grill etc some of that was damaged also, or there was timing chain issues before.

So, I'm assuming this is evidence of severe head gasket leaks?

Pictures here

Oil is all over bottom of starter also, but I really cant find where its hitting that. Very tight...

Oil all over the bell housing only indicates that there is a very small leak and its splattering like that because of the wind from driving. If you haven't noticed a great deal of oil loss then don't worry about that. I think the oil pressure sender unit has an o-ring or something, I just replaced mine not too long ago (took only 5-10 mins) and everything is fine now. replace the sender unit first and go from there.

You've got a major cleaning job so you can figure out the source and pace of the leak(s). That's your oil level sensor that's leaking. That's the one on the side of the oil pan. Your lower harness doesn't look good. There are signs of prior repair at the oil level sensor plug. There's still a good chance your oil pressure issue is just sensor and/or wiring. But the leaking fluids are the more pressing issue for now, especially if you're getting coolant that far back.

As far as being a small leak, can't be. I lost almost 2 quarts in last week, so its NOT driving anymore.
I've also already played the clean up game. This has been going on for a while. Its impossible to inspect the rear drivers side while running without taking off the intake manifold etc (unless someone knows how). The rear upper is where I orig thought, cleaned and oil seemed like it was only streaming inside the bell housing. .
This much oil, and now coolant, isn't this classic head gasket for the 104?

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I didn't know you lost that much oil. Nonetheless, clean it up, change the sender and go from there. Why manifest a head gasket job on yourself? Start with the smaller chores first.

I like your thinking... Hoping someone will chime in with the magic place 104's always leak like this other than the head gasket.

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got advice on using heavier oil (15W40 vs my 5W30), and I'm also wondering if it could be the gasket between the exchanger and the block? Apparently its rear block under intake manifold... there is oil all over the bottom of the starter back there and that's where its running from. Difficult/tight to inspect. If so I'd MUCH rather deal with valve cover or heat exchanger gasket.
Again, there is only oil coming from the Drivers side under intake and very back, where its very tight/difficult to inspect. Even wondering if I need a bore scope (ummmm Roy did tell me to get one a loooong time ago).

berryrice, deanyel
 

So, car on ramps; I am lying on my back, doing stomach crunches to gain some altitude. Can I get to the sending unit?

"" Very discouraged, because I got this car for its reliability and safety. I'm retired vet and going on my 3rd year of unemployment sans a couple of consulting gigs, so we're broke. I'm HORRIFIED this is going to be expensive. This is our ONLY transportation, as my Truck rear end went out 2 weeks ago. ""

But it is a 18 year old car that was expensive when new, not too expensive to buy used, but still needs sometimes expensive parts to fix. You really need to take a hard look as to whether this is cost effective transportation for your situation. I've seen too many people with minimal funds try to drive odd / expensive to fix cars with disastrous results. Renault Fuego / Alliance, SAAB 900 , Yugo , Eagle Premier ( Renault sold by Chrysler dealers ) , 90's Pontiac Lemans ( Opel? )

As for the head gasket, these motors leak oil from the front of the head gasket where it hits the timing cover. I'm not sure there is even a oil pressure passage at the rear of the head.

The leak might even be the oil filter housing as these have a removable cap rather than a spin on filter.