GEDaggett

Is there a spot on the M104 block to hook up an aftermarket oil pressure gauge. I am nervous about my dash gauge not working. I want to hook up a temporary oil psi gauge till I can get the other issue figured out and resolved. Any info would help.
Thanks

Gary

Real1shepherd

Curious...what's your issue with the stock gauge? Mine reads maximum while in gear & moving, but drops to zero at the light or while idling. It started doing that really early in its life though....I would have figured it out by now, but the ex had the car all these yrs. I would think that wherever your oil sending unit is on the block, you could substitute a metric threaded adapter and hook up a temp gauge. Warm up the engine, rev it, record the psi and then at idle-that should give you a realistic output of your engine oil pump.

That's how I've always checked actual engine oil pressure in the past-don't see why the 104 would be different.


Kevin

GEDaggett

At start up it does it's diagnostic where it goes full pressure and thhn drops down to 0 even at full throttle it shows no pressure. I removed the oil fill cap at idle to check and there is a good amount of flow but I just want to have a real time monitoring of PSI. It is something I have done with all my rebuilds because If your on the highway and loose oil pressure you may not realize it till it is too late. Typicall there is a port or a spot to put a fitting into. I may have to put one in place of the stock Oil pressure sending unit in order to get a good reading.

Brian_I.

My oil pressure gauge goes up when I'm driving but kinda flutters around while idle, any thoughts on that? I know I have a small oil leak but could that be the cause of the fluctuations?

Real1shepherd

That's what I was saying; if you can't find a plugged port in a oil gallery somewhere, just use the old sending units'.

I gotta think it's Benz problem, because mine has been doing this forever-dropping to near zero at idle. It's BS though, because if you're going to have a oil pressure gauge, it should work full range.

Kevin

GEDaggett

Well my situation has entered a little different stage than the sending unit bug. I have low flow to the cams and it has started making a bit of noise so I shut her down. i am going to be making a pressure testing unit with a new oil filter cap and getting an actually psi reading at the filter housing. Apparently there are are three things that can happen causing this outside of the oil pump. I ruled out oil filter clog as I started her up without the filter and pressure did not pump up. I also think that I ruled out total oil pump failure as I started the car without the oil filter cap and it filled up the res in a hurry.

The following are my potential issues that I see. There is a pressure bleed off in the oil filter housing that can stick open and bleed off pressure. I will be replacing this first. There is also delivery tubes that go directly to the cams and oil them. The seals on this can fail and that will be next if the oil pressure bleed off doesn't fix it.

Any other suggestions would be welcome. I will update with status.

Real1shepherd

Whoa....you do seem to have a real potential oil delivery problem. Follow your instincts on this one and don't run the engine more than you have to-definite NO on a trip somewhere.

DO keep up posted, as this is extremely relevant to us all-what you find as the cause. Nothing can kill an expensive engine faster than oil delivery failure.

Kevin

GEDaggett

Soooo, I tested oil pressure with a tester I made with a spare oil filter cap and a parts store aftermarket oil pres gauge and it came up to 80 psi and stayed there. It also had a very nice 5 psi per second bleed-off after shut down showing a good sealed system and a strong oil pump. So that led me to investigate the condition of the cams and get a look under the valve cover to look at the chain guides to see if I was misdiagnosing the sound. I was absolutely shocked to find a bolt sitting in a very precarious spot next to the exhaust cam sprocket. Closer examination showed that I had 1 bolt come loose and was flung up into position in the absolute only place that kept it from causing a catastrophic event in the timing system. I had a second bolt 50% removed and only one partially loose. The noise I heard that I thought was the cam was actually the cam sprocket coming loose and wobbling on its remaining mounting bolts. Needless to say I dodged a serious bullet. I will take a picture of this whole thing and post it in a new thread next week as I am astonished at how the whole thing happened. The good news is I will replace the bolts, torque then down and be done only having spent about $10.00

Real1shepherd

! If we're talking about the same thing here.....these 103 engines have two front camshaft bearing bolts that are KNOWN to strip out-usually fixed on a thorough head job. You can repair them easily enough with Heli-Coil kits for the proper bolt. Maybe we're talking about something different here. Are you talking about the camshaft sprocket bolts themselves?

Kevin

GEDaggett

m104 engine. cam shaft sprocket bolts on the exhaust side. one of them came completely out and then the other two started backing themselves out. I don't know if I had my torque wrench set incorrectly or just missed one of the bolts but it backed itself completely out. I figure I was about a couple of miles away from a complete catastrophe. I am very glad I was going all Columbo on this or I never would have seen it. Luckily the receiving threads are still good.

2oCLKoo

Replacing the oil pressure sending unit switch sensor just below the filter housing.
I've located it, and it looks like I need to use an open ended wrench. Any tips? 17mm works I found!

symtomps
car cuts out after driven 1 hrs on highway or 45 in some light traffic.
my pressure drops to 0 on idle.
at start it is at 3 and then goes to around 2. Idle and 3 when driving. Until it gets hot
goes to 0 and bounces up to 1-2 on side roads traffic. Only on highway I can keep it up to get home after driving and reach in normal temp.
I have done coolant service and I put some 0w40 this august so I know I should of run 10w50 or so. Thanks looking for the right wrench or procedure needed.
sorry about old post.
1993 w201 2.6 190e

2oCLKoo

About head gasket.
oil mixing with coolant.
I've changed the coolant.
or any ways to solve the low idler at stop when engine is warm to optimize temp mine is 80 after coolant change.
any tips on how to fix the car from stalling when the oil pressure drops or is this a pressure so sending unit issue it seems.

any tips for me I'd appreciate
new to w201