OM617 - no oil pressure when cranking - PeachParts Mercedes-Benz Forum

OM617YOTA · #1 12-31-2012, 06:00 PM

Greetings all!

I've spent many an hour poring over the information here on your forums, and you all have saved me countless dollars and hours already. Thank you for your help already given.

I now need more input. I've searched your fine forums and have found nothing.

I have swapped an OM617 into a '90 Toyota pickup. It is now time to start for the first time. I've got the glow plugs pulled and have been cranking the engine over while purging the injector lines of air and such, while keeping an eye on the mechanical oil pressure gauge. Not even so much as a quiver, though I've cranked the engine for probably 2+ minutes combined. I pulled the oil filter and took a peek - a bit of oil in the bottom of the housing and that's it. I pulled the turbo oil supply line - not a drop coming out. Pulled the oil fill cap - not seeing anything being flung around the top of the motor. I filled the oil filter housing with oil(knowing it will drain back into the sump) and reinstalled filter+cover/rod. Cranked, no luck.

At this point, this oil issue is the only thing keeping me from reinstalling the glow plugs and firing her up. What should I do next?

Thanks all, truly appreciated.

Edit: The O-rings on the end of the rod that goes down the center of the oil filter are shot and will be replaced. Other posts show people having a slight improvement in hot idle oil pressure after replacing these O-rings. Is this my problem, letting the oil drain right back into the oil pan without going through the filter and into the oiling system?

Not in a huge hurry to start this engine with apparently zero oil flow.

mach4 · #2 12-31-2012, 06:18 PM

Quote:

Originally Posted by OM617YOTA

At this point, this oil issue is the only thing keeping me from reinstalling the glow plugs and firing her up. What should I do next?

I'd check for flow first, suspecting a possible bad gauge. A quick way to check flow is to take the gauge line off at the oil filter and crank. If you've got flow, then swap the gauge or figure out how you can adapt something to test the gauge by pressurizing the line. You could also loosen the top to the oil filter housing and crank, but that would create a bigger mess. If you use that method however you would know how long it would take to fill the housing and get oil pressure.

Double check the oil level.

I don't think the o-rings would cause your problem.

kerry · #3 12-31-2012, 06:23 PM

Is there oil in the sump?

vstech · #4 12-31-2012, 06:36 PM

ya may want to pull the lower pan and inspect the oil pump chain...

engatwork · #5 12-31-2012, 06:37 PM

How was it running prior to the swap?

OM617YOTA · #6 12-31-2012, 08:07 PM

Thank you for the replies!

Yes, there is oil in the sump. 15w-40 Delo 400.

The engine ran fine before it was yanked from the donor car, an '83 300SD w/ 273k on it. Before it was yanked from the car, I started it cold, drove it around the junk yard, let it get up to full operating temperature, checked all fluids, etc. All was well then.

The line from the oil pressure fitting to the gauge is translucent poly tubing - easy enough to see oil in the line, and I've got nada. I'll try pulling the cover on the top oil filter housing and see if it pumps anything up there, though that will probably happen tomorrow.

The oil pump itself was my worse case scenario - hoping there is something else. Should it build oil pressure while cranking, or only after starting?

Thanks all! Please keep the ideas coming. Have a happy and safe new year celebration.

barry12345 · #7 12-31-2012, 08:16 PM

Sounds like the oil pump is not primed. Might help to pour a litre of oil in the filter container with the filter out. After all what else could it be if the oil pressure was fine before you pulled the engine? Almost if not all normal engines in decent condition should cold pump up some pressure with some cranking. I doubt if the relief valve has fallen out of the oil pump but that is another remote possibility.

qwerty · #8 12-31-2012, 08:21 PM

Quote:

Originally Posted by barry12345

Sounds like the oil pump is not primed. Might help to pour a litre of oil in the filter container with the filter out. After all what else could it be if the oil pressure was fine before you pulled the engine?

Agreed. You might even try some of the more viscous oil additives like Motor Honey or STP in the filter housing (element removed.)

kerry · #9 12-31-2012, 08:32 PM

Something's funky here. An 83SD should not have a mechanical oil pressure gauge.

OM617YOTA · #10 12-31-2012, 08:41 PM

I installed a mechanical oil pressure gauge when I swapped the engine. Easier and more direct, than trying to fit the Toyota oil pressure sender to the MBZ diesel. In the future I will probably do this to clean up the interior and use the stock Toyota oil pressure gauge in the dash.

I'd suspect the gauge of being at fault(It's brand new, though that makes no difference, I've gotten more than one new part that was DOA.) if I was getting any other signs that oil was flowing. Oil at the top end of the motor, oil in the oil filter housing, oil at the turbo supply line, oil in the clear poly tubing leading to the pressure gauge, anything.

Thanks all, I truly appreciate the help.

mach4 · #11 12-31-2012, 09:20 PM

Quote:

Originally Posted by OM617YOTA

The oil pump itself was my worse case scenario - hoping there is something else. Should it build oil pressure while cranking, or only after starting?

It will build pressure. When I did a compression test on my JY engine, I got about half a bar for each cylinder within 3-4 compression cycles.

Since the engine ran fine in the junk yard, I think I'd just start it. The possibility of something going south in the interim is almost unmeasurable provided you didn't drop something into the pan or something else catastrophic in the meantime.

I'd be ready to stop it within 3-5 seconds if no pressure shows and have a block of wood handy to slap over the turbo intake in case the shutoff doesn't work for some reason. I'll bet the pump is just cavitating and needs a bit more speed to get its first prime.

vstech · #12 12-31-2012, 09:23 PM

I'd still pull the lower pan and inspect the oil pump. during the swap, you could have gotten some plastic, or something else into the pan, clogging the pickup screen... no Idea, but I'd NOT crank it any more until I verified the pump was clear, and the chain was intact.

qwerty · #13 12-31-2012, 09:31 PM

Quote:

Originally Posted by vstech

...you could have gotten some plastic, or something else into the pan, clogging the pickup screen...

Plastic in the oil pan…never would have thought of that. Not in a million years. Maybe a polyethelene tarp fell down the dipstick tube!!! Missing any tennis balls?

vstech · #14 12-31-2012, 10:13 PM

Quote:

Originally Posted by qwerty

Plastic in the oil pan…never would have thought of that. Not in a million years. Maybe a polyethelene tarp fell down the dipstick tube!!! Missing any tennis balls?

...
I guess it's hard to imagine what could happen during a repower...

kerry · #15 12-31-2012, 10:56 PM

When I change the oil in my 617's it takes a few seconds of running before pressure shows up on the gauge. I've never put a stopwatch to it to compare to how fast it shows up on a normal start but it's definitely longer. I've also never looked at the camshaft while the pressure is building after an oil change so I don't know if oil is spraying on the camshaft during those first few seconds. I'm guessing it probably isn't but most of the pressure is disappearing into the filter canister as it fills up. I've certainly never just turned over a 617 after an oil change to see if I see pressure prior to the engine running. My suspicion is that you are experiencling this lull in pressure after an oil change and that it will be ok after the engine runs for a few seconds.