Measure at oil temp 80C.

 

Thank you so much.
So, our cars don't have oil pressure warning sensors? Some mechanics told me if I have low oil pressure, it will pop up on middle screen

 

That’s pretty low, 10psi at idle.

 

Have you measured yours?

 

Is the rattling from the front of the engine like a timing chain, or all over the engine like lifters?

I had lifter noise, very loud all of a sudden after never having noticed it before. Could hear it with hood closed 30 feet away. I got the oil changed which helped a little, but it wasn't fixed. Then I added a quart of Marvel Mystery Oil (a gallon of it is cheap at Walmart) to the engine oil (still within range). And then the problem got better and better. It seems to be carbon buildup over the years, but I don't know why I suddenly got it real bad and all over the engine. Just changed the filter only and it had caught a lot of crud, so I'll run a while with the new filter, then change oil + filter.

I am slightly concerned about running too long with MMO in the oil, because it could degrade those 2 O-rings that are only accessible with timing cover removed. I don't know how safe MMO is for those. For that matter, how safe is Liqui Moly?

At the same time I got very concerned and what if it was the timing chain? So since we have only one timing chain and an external tensioner for it, I changed the tensioner. Don't have to open the timing cover. I'm at 160K miles and it might prevent a future problem. Engine runs nice now.

I had planned to remove and clean the oil pan with the oil change, which should really do after flushing the engine, but that's a big job on the W163. Front suspension has to come apart as I recall.

 

This is the bottom of the oil pan. no signs of goo.
My sound is not a lifter, all ticking is from injectors I think.

Strange whine, appears 0:25

youtube.com

After the oil change, I had a 5 minute of strange whine gone.
I was happy, revving checking the sound and suddenly it reappeared again. (0:25 in the vid)
This engine doesn't seem like it is abused since the inside of the pan was clean. I am pretty sure this is from the oil pump.
the serpentine belt and accessories are dead quiet. The moment of truth(oil pressure) will be revealed tomorrow, but I am just worried to drive the car around.

Yes, LQM flush works. But I don't have a tool to lift the engine to take off the lower pan.

Maybe I should try changing the tensioner. I am unsure oil pump is also connected to the chain tensioner. Is that alternator out job?

 

Let's make sure what this thread is about. OP question was about testing oil pressure.
I have provided WIS document about the test in post #2. Take it or leave it.