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

[Vivek]

Well I saw no real signs of damage on the valve, but I really have no clue what to look for. Hopefully it's just the valve and it'll be all good upon reassambly.

[bmwman91]

It is good that you got the updated parts in. Was the old one stuck or jammed at all?

Considering how long the thing sat for, I wouldn't be surprised if the inlet felt pretty dry.

If this wasn't it then I am totally stumped. The only other thing I could think would be that there are no pump geats in the timing case, but if it was running fine before and the case was not off at any point then that is not a possibility.

[Vivek]

Anyone? I'd like to assemble this ASAP but I don't wanna put back together and find out it's like the oil pump or something else.

[Vivek]

Okay FINALLY got both pans off. The lower one took forever because I couldn't get it to separate. On the upper I stripped one of the torx bolts on the bell housing and that took a couple days to remove. Fucking pain in the ass. Anyways, here's some pics:
Oil pickup:


Gasket around the oil pickup:

Oil pickup port. Note that it looks/feels completely dry. Would a stuck relief valve cause that?

And here's the valve I pulled out


Parts I have ready to go on are new OEM upper and lower gaskets, new tube of hondabond, and all 4 parts of the valve (upper, lower, spring, circlip). The valve is the updated nylon design.

[roguetoaster]

If you need to pry on the pan there are tabs on the front you can lever against (as you pry you can stick a utility knife blade in the area that opens). That combined with a few taps from a rubber mallet should take it off.

Just don't use a chisel or screwdriver between the sealing surfaces except as a very last resort.

[bmwman91]

I don't know of any really easy way to get the pan off with the adhesive. Sounds like some brute force is in order.

[Vivek]

I'm running castrol regular oil 20w50. I pretty much smeared it around everywhere over the gaskets on both sides. I'm pretty sure it was all around every bolt hole and lines in between the bolts. It's now a bitch to get the lower pan off. Is there any way to do it other than hammering a chisel in there? And since I took the lower pan bolts out, I'm pretty sure my issue is that they weren't torqued enough. I'll need to find the spec for these bolts and a wrench that'll do it.

[bmwman91]

What kind of oil are you running? Synthetics will just leak a lot and it is tough to avoid if you use stock paper gaskets. RTV / Hondabond will help, but not stop it. The only way to be sure is to skip the gaskets and just use some Permatex Ultra Grey gasket maker, which is also a 24 hour process since you can only finger-tighten things at first and then torque it down after it cures. Doing that also makes it damn hard to get things apart again in the future. I would not skip the gaskets though since that changes some tolerances here & there.

Did you run the Hondabond stuff all the way around every bolt hole? Only running it around the outside will lead to some leaks.

Another common leak spot is where the two rubber profile gaskets butt up to one another on the passenger side. Oil pools there and will run out of the small gap a soon as you turn off the engine. You should clean that area with some alcohol and smear some Permatex Ultra Grey RTV over it and work it into the gap. Let it cure for 24 hours or the engine vacuum will just suck it into the timing case area.

For reference, my MM 2.1L M42 has less than 5k miles on it and it weeps oil like crazy (1qt / 1000 miles). I am running Castrol 10W-60 TWS oil which is an awesome oil (damn well better be for $18/L), but it weeps like a motherfucker. I am switching back to Castrol 15W-50 since it doesn't leak nearly this much.

[Vivek]

Another thing. It looks like my brand new oil pan gaskets have been leaking. I'm working on pulling my pan so they'll be replaced, what should I do differently to ensure they don't leak? I used VR paper gaskets with hondabond on both sides. I believe I guesstimated the torque specs because my wrench doesn't go low enough, but I'll have to double check that. If they're safe to torque to 20ftlb I'll do that upon reinstallation.
Lower pan:

Upper:

Timing case could be leaking slightly, I didn't touch those gaskets. but this is leaking a LOT.

Amount of oil leaked after about 1 minute total of running

[Vivek]

If I pull it all apart I might as well replace it. The valve itself is only like $15, the two gaskets that I'll definitely need to replace if I pull the pans cost that much each.

[bmwman91]

Sure. Hopefully the valve is the issue so you don't waste $40! I usually try to pull things apart before buying parts, but waiting an extra few days isn't always an option.

[Vivek]

Well, I'll pull my pan in the next week and update with pics. I'll make an order for the valve parts right now. Thanks so much for your help so far.

[bmwman91]

Yeah the bypass is the round thingy with the circlip in the lower left of the photo.

The oil pickup is attached to the upper pan, and the oil passes through the hole to the right of the bypass in the photo. You absolutely need to make sure that none of the threads in the timing case are stripped. One failure mode on these engines is that the bolts holding the upper pan to the timing case fall out, and then the gasket that seals the oil pickup route between the timing case and upper pan implodes. So I guess that could have happened too, although it seems like you would get a little oil flow.

[Vivek]

It was dry for maybe 2-3 months I think? Could have been a little longer. My only thought is maybe the rattle before it was pulled was caused by a failing bypass valve not getting adequate pressure on startup

So in this pic is it the little black circle in the bottom left held on by a circlip? I'm totally blanking but where the hell is the oil pickup? Edit so I think the pickup is attached to the upper oil pan. Is there anything special I have to do when installing the pan to make sure that works? Could that be my issue?

[bmwman91]

Yeah that sounds about right. I have only ever replaced the bypass parts with the timing case off of the car, but I think that you should be able to do it with just the oil pan out of the way.

If it was running fine before and nothing got changed on the engine during the swap then I really don't know what it might be. I can't see any reason why the bypass would choose to poop out now. How long did the engine sit for?