low oil pressure on idle when engine warmed up

[wynanddb]

Had a look at the filter, no metal filings :)
HAving the oil checked is a good idea, maybe its getting contaminated with diesel from a faulty injector.
Running 15W40 as per Daimler/Chrysler specification - TIA (this is africa ;)) - was about 100 deg F this weekend here, 38 deg C
When I assembled the engine, the oil non return/pressure valve was very loose in the timing cover, so I am planning to replace it, as well as inspect the bearings. While I am at it, take the turbo to a reputible shop to have it checked.
All of this will have to wait till Jan next year though, on my way to Mozambique for the holidays :)

[Old Crows]

OK... its SA! Not different than Texas in the summer with over 100F on many days. Probably 125 just above the asphalt....


Hey... I don't know squat about these engines....

BUT! I'd check to see that you have completely filled the cooling system. Do these motors have an 'oil-water' inter-cooler for the engine's oil? If the inter-cooler has an air bubble trapped in it the oil temperature may not be regulated closely.... thus the loss of pressure due to higher than normal oil temperature when the engine goes back to idle.

Yeah... I know.... probably not right.....

[talkinghorse43]

Originally Posted by wynanddb

I think I should add a gauge to that port, I am finding it a bit difficult to orientate myself as to where the port is. Would you mind having a look at the two attached pics and indicating as to where I should look?

As far as the nozzle is concerned, I inserted new nozzles, if one did come out, wouldn't the pressure be low even on startup?

PS. The fotos is before the rebuild..

Another thing, I havent used a 50/50 mix of water and coolant, just a very light mix because I wanted to check for leaks first, could it be that this allows the engine to run just that slight bit hotter which would just thin the oil enough to give a low pressure reading at idle when the engine is hot?

The port is just below the oil cooler.

What pressure do you see on startup?

How hot is the engine running?

[wynanddb]

Originally Posted by talkinghorse43

The port is just below the oil cooler.

What pressure do you see on startup?

How hot is the engine running?

Thanks, I think I am going to get a guage for that port, it looks like a lot better place to get the actual pressure.

On startup the pressure starts at 0 and within 5 seconds is up to (1/2), the guage is not marked in psi, but marked in 5 segments. 5s after startup the pressure pegs right in the middle (1/2), stays the same for about 5 miles of driving, when coming to stops it goes down to (1/4). After 5 miles when I stop at home she goes doen to Zero, if I flick the accelerator she'll come back to about about 1/8, once cooled down a bit the oil pressure returns to normal.

The heat gauge is marked in what I think is degrees C, and she runs between 90 and 100 degrees C thats 194 F to 212 F

One thing that bugs me is that when I reasembled the engine, the oil non return/pressure valve situated in the timing cover was very loose (if you held the timing cover with this thing to the bottom it would fall out). As far as I understand this valve keeps oil in the oil filter when the engine is switched off. (picked that up from a Dr A post). So what is the chances that as the oil gets thinner its actually making its way past the sides of the valve returning oil to the crankase through the timing cover rather then pumping it up into the engine (or partially at least)?

[talkinghorse43]

Originally Posted by wynanddb

Thanks, I think I am going to get a guage for that port, it looks like a lot better place to get the actual pressure.

On startup the pressure starts at 0 and within 5 seconds is up to (1/2), the guage is not marked in psi, but marked in 5 segments. 5s after startup the pressure pegs right in the middle (1/2), stays the same for about 5 miles of driving, when coming to stops it goes down to (1/4). After 5 miles when I stop at home she goes doen to Zero, if I flick the accelerator she'll come back to about about 1/8, once cooled down a bit the oil pressure returns to normal.

The heat gauge is marked in what I think is degrees C, and she runs between 90 and 100 degrees C thats 194 F to 212 F

One thing that bugs me is that when I reasembled the engine, the oil non return/pressure valve situated in the timing cover was very loose (if you held the timing cover with this thing to the bottom it would fall out). As far as I understand this valve keeps oil in the oil filter when the engine is switched off. (picked that up from a Dr A post). So what is the chances that as the oil gets thinner its actually making its way past the sides of the valve returning oil to the crankase through the timing cover rather then pumping it up into the engine (or partially at least)?

Here's another picture (post 76) of that port from rlent's "Was Ist Das" thread:

http://sprinter-source.com/forum/sho...ght=das&page=8

Even though not knowing what the units are, those pressure values sound low. Mine when cold at anything off idle is pegged at the relief pressure of 85+ psig, and that's with a thinner oil (0w40) than you're running.

That's running a little hotter than mine usually runs (180-200F), but then I rarely drive with the outside temp that high.

I've never had my engine apart, but the valve you're describing could be OK if it's simply meant as a check valve to stop backflow. But, to be sure, I'd PM the good Doktor (abittenbinder).

[wynanddb]

Ah, got the location thanks, when I am back from leave I'll be hooking up a decent gauge there, permanently...

Send the good Doktor a PM :)

If all else fails I'll replace that valve, as well as check the big-ends (although I doubt theyd be cooked after only 10 miles, unless they ran dry or the crank wasn't cut correctly)

[abittenbinder]

Originally Posted by wynanddb

One thing that bugs me is that when I reasembled the engine, the oil non return/pressure valve situated in the timing cover was very loose (if you held the timing cover with this thing to the bottom it would fall out). As far as I understand this valve keeps oil in the oil filter when the engine is switched off. (picked that up from a Dr A post).

So what is the chances that as the oil gets thinner its actually making its way past the sides of the valve returning oil to the crankase through the timing cover rather then pumping it up into the engine (or partially at least)?

Even if the back-flow valve was completely missing, it would not affect idle oil pressure once pressure had built up (from a cold start). Pressure build up time would be affected but not the pressure, once filter housing had refilled.

Doktor A

[wynanddb]

Ok, Doctor A said that vavle would not influence the oil pressure, even if it was missing. So down to bearings, or maybe Turbo, or guage, I guess. Not ruling out the oil cooler just yet, but if it was faulty I would have expected some oil in the water...

[Aqua Puttana]

Originally Posted by wynanddb

...
Not ruling out the oil cooler just yet, but if it was faulty I would have expected some oil in the water...

If you mean a leak in the oil cooler I would think that if that were leaking to the point of lowering oil pressure even in a 10 mile drive you would notice significant loss of oil level. FWIW. vic

[wynanddb]

I was more thinking in the line of oil cooler blockage