M42 running VERY loud (video), low oil pressure light is on

[wazzu70]

Yeah, if pressure actually is zero, then it's gotta be the pump. I'd think anyway. If he got the engine from a friend and it was in running condition, then I can't imagine how the pump would have failed.

Depending on the routing of the oil system to the sensor/oil filter block. Is that the first stop along the path? I cant remember.

If the main galley is before that and its missing a squirter the oil system will not build pressure because there is no restriction. The oil just dumps out the open hole. 0 pressure does not mean 0 flow, it means there is not the right amount of flow restriction.

Maybe remove the oil filter housing block and see if any oil exits the pump when you rotate the crank.

The oil pump is a gerotor driven by the crank snout. Not a lot to fail there.

[kwill22]

Also if the pump is dry It won't prime since your engine has been sitting.
I've had similar experience with the hydro pumps on lifts

You could also try to prime the pump manually by turning the crank. Rig over the lower pan and hold a container of oil to the pickup tube and see if it'll suck.

[bmwman91]

I've said it all along I'm blaming the oil pump

Yeah, if pressure actually is zero, then it's gotta be the pump. I'd think anyway. If he got the engine from a friend and it was in running condition, then I can't imagine how the pump would have failed.

[bmwman91]

Vivek, you put an oil pressure tester on there and saw zero PSI right? Or have you been going based on the stock pressure sender all along? It is entirely possible that the sender is just crapped out and something is up with the tensioner piston. You put a new one in right? Take it back out and see if it is full of oil. If your oil has been circulating then it should be an oily mess. Contrary to one of the suggestions above, the only really safe way to install it is to decompress / expand it and then install it. Putting it in compressed and waiting for the chain to smack the rail around enough to break it loose is asking for broken rollers on the chain...which WILL end up in the oil pump.

[bmwm42]

I've said it all along I'm blaming the oil pump

[kwill22]

We're absolutely positive that the timing is on par right? Just trying to eliminate things

Sorry to hear man, I think a bunch of us have been to the point where we wanted to take a sledge to the car. I know I have.

[Vivek]

Shit dude, really sorry to hear this. I cannot imagine what it is at this point if the oil pressure light is on (and you measured a big zero), other than a completely destroyed or missing set of oil pump gears. You said that this engine was running strong when you bought it, and you didn't swap or do anything with the timing case right? The only way I can think that the oil pump is not operating is if the PO of the engine blew out the gears and sold you a dud.

I know how you are feeling as I was there about a year ago. I had waited a year for a custom M42 to be built and had a valve spring crap out 70 miles in. Pulled the engine and shipped it to the builder to get fixed. Put it back, things were going well, and then another one broke at 1000 miles. I was seriously going to get the head fixed and sell the bastard. Buy a used Civic and get from A to B with no more bullshit. Thankfully, I had some guys on M42Club keep up the encouragement (Warsteiner, wazzu, DesktopDave) and it turned out fine. It took hours of bloody knuckles, sweating and anger to get through it, but it all worked out. You'll be fine too, and in a few months it won't be a big deal for you.

I think I'll pull my oil pressure sender again, start it up, and see if it squirts oil. Maybe I'll pop the oil cap off too and see if I can see anything. Is there anything I can do to make it less bad that my car is pretty much running with no oil circulation? Anything I can lube manually to try to help it out? I started it yesterday shortly after filling it with oil with the hope that at least part of the engine would still have some residual oil on it.

I've already contacted two shops requesting they fix it. One thinks oil pump or timing chain guides. The other hasn't responded yet, but the second shop is less than 100 miles from my house and I have AAA towing up to 100 miles. Also I got the second recommendation from a friend and they're classic bmw specialists.

Anyways, I got the engine from a close friend, saw it running days before it was pulled. I have full confidence it was 100% fine before it was pulled, other than the aforementioned timing chain rattle.

Maybe it's the oil pump, but idk how that would happen. Maybe I installed the timing chain tensioner wrong, and the oil sensor broke or is hooked up wrong so it's reading 0 while it is actually getting pressure. All I know is that I haven't driven my car in 7 months and I'm pissed as fuck. Never been so frustrated and fed up ever.

[bmwman91]

Do as stated and see if oil is flowing to the valve cover. That should answer quickly if oil is circulating or not.

If its not flowing, you either have a bad oil pump (unlikely) or a big leak in the oil system. One area this can form is if a piston oil squirter off the main galley fell out.

Check the easy stuff first though. Probably something easy :)

Before he changed the relief valve, he put a pressure tester on where the sender is and got a 0PSI reading, and no oil came out of there. If it was a big leak somewhere downstream, I think that he'd at least register something there, no? This is like the M42 caper of the decade right here. Not sure what's at fault, but the culprit sure is a bastard!

[wazzu70]

Do as stated and see if oil is flowing to the valve cover. That should answer quickly if oil is circulating or not.

If its not flowing, you either have a bad oil pump (unlikely) or a big leak in the oil system. One area this can form is if a piston oil squirter off the main galley fell out.

Check the easy stuff first though. Probably something easy :)

[bmwman91]

Shit dude, really sorry to hear this. I cannot imagine what it is at this point if the oil pressure light is on (and you measured a big zero), other than a completely destroyed or missing set of oil pump gears. You said that this engine was running strong when you bought it, and you didn't swap or do anything with the timing case right? The only way I can think that the oil pump is not operating is if the PO of the engine blew out the gears and sold you a dud.

I know how you are feeling as I was there about a year ago. I had waited a year for a custom M42 to be built and had a valve spring crap out 70 miles in. Pulled the engine and shipped it to the builder to get fixed. Put it back, things were going well, and then another one broke at 1000 miles. I was seriously going to get the head fixed and sell the bastard. Buy a used Civic and get from A to B with no more bullshit. Thankfully, I had some guys on M42Club keep up the encouragement (Warsteiner, wazzu, DesktopDave) and it turned out fine. It took hours of bloody knuckles, sweating and anger to get through it, but it all worked out. You'll be fine too, and in a few months it won't be a big deal for you.

[uturn]

If I had seen you post earlier I would have said go ahead and change out the oil pump.... another $50 part + $15 gasket for piece of mind. The two profile gaskets - VR ones don't fit properly, use the BMW ones to seal properly. The tensioner issue, I think you might have stretched your timing chain. To properly install it you have to break it down, compress it two or three clicks in so it stays in(the last click will disengage the piston and it will come back out). Install it then push on the rail to engage it. It'll pop out and adjust itself as needed. There's also the possibility of valve tick because of bad lifters but that could also be because of no oil getting to them. I feel for you man...

[roguetoaster]

I am very sorry to hear that the same issue is back after all of that work.

1. Take the tensioner out, separate it, inspect it. If all is well visually make sure it has oil in it from the get go, reinstall and try again.

2. Assuming the rattle is still there start taking off things you can to check to see where oil is going/not going (VC, oil filter cap, oil filler cap). Maybe even take the cap off and put clear plastic over the opening to check oil sling. If oil is circulating everywhere then IDK what else it could be besides magical low pressure.

I can't remember if you had the front cover off, if not maybe you have something loose or poorly seated in the timing system. Save the bridge driving off thing for later when you find the simple problem that was right in front of you all along.

[Vivek]

Well I would drive off a fucking bridge but I don't have a car to take.

It still won't FUCKING work. I got the new part. Oil it up. Put it back in. New hondabond. New gaskets. Spent a fucking month doing it. I started it up just now and it has the SAME exact issue. Oil pressure light on, loud as fuck chain rattle. Fuck this I'm taking it to an E30 shop and bending over for whatever they're gonna charge me.

Could the new chain tensioner possibly be a dud? I would be so fucking mad if I spent so long replacing a part and it's something else that would take my 5 minutes to replace.

I've run it for about 30 seconds total after doing this. Started it up, it revved to 4k and started dropping, stopped because I didn't wanna fuck it up. Realized I didn't check if the oil pressure light was on, maybe it's just the tensioner getting pressure. Started it up again, revs to 5k, light is on, turned it off. Looked under the hood and realized the throttle cable was not seated, fixed that…started it up again just to check. Idled perfectly, but the rattle is still deafening.

[bmwman91]

Yeah, it is probably a good idea to dip it in some motor oil.

[Vivek]

I should lube the valve before putting it in, right? Stupid questions but I don't wanna screw up something simple on this job by not asking.