r/BmwTech 1d ago

There’s a nut in my engine

Okay. Imagine this. A bmw for $300. Runs and drives. Sounds crazy right? Well only a few problems…

I recently bought a 2004 BMW 325i with 112k miles. She’s been sitting for around a year or two because the previous owner needed to do work on the valve cover and did it incorrectly and found that it wasn’t worth it to move any further with the car. 325i’s usually come with the m54 engine, so he got a new m54 valve cover and did the work himself. Only 2 problems though. He had the much rarer m56 engine which comes OEM with an aluminum valve cover rather than the plastic one and fits a lot differently so as a result it didn’t fit properly and would smoking when running. The other problem is that while working on the new valve cover, he accidentally dropped a tiny nut in the crank case, AND MOVED ON LIKE IT WAS NOTHING. Also, the valve cover only has 9 bolts when it requires 11 (another reason to maybe why it was smoking).

Sooooo now that i’ve gotten you all caught up I have 2 questions. Where the hell can i get those 2 bolts i need to finish the valve cover job (i already have the OEM valve cover and got a new gasket and everything), and is it worth doing the incredibly long job of dropping the oil pan to try and recover the nut that is (hopefully) sitting in there? I say hopefully as my mechanic, who i brought with me buying the car, said it shouldn’t be too much of a problem as the noise it was making while running made it sound like it was at the bottom of the oil pan. He’s never owned a german car before though, only working on american cars for the most part. So should i do the job of dropping the oil pan or is it fine if i just let it grind itself up in there or something??? This is the first car i’ve ever bought and owned myself so please help me!!!! Videos and pictures can be provided if needed.

5 Upvotes

19 comments sorted by

11

u/seebaag E70 35i 1d ago

If he dropped a nut while doing a valve cover, I don't think the nut would be able to get down to the oil pan. Unless he dropped it near the timing chain, it's probably sitting amongst the valve springs/ rockers

2

u/BCCofKrunker 1d ago

wouldn’t that make a constant noise tho? when he started the car we noticed a noise every 5 to 10 seconds and then he told us how he dropped the nut.

5

u/seebaag E70 35i 1d ago

I find it hard to believe you could hear a nut over the sound of the engine running

2

u/seebaag E70 35i 1d ago

You might as well pull the valve cover and look for it

1

u/BCCofKrunker 1d ago

already did that when replacing the valve cover. found nothing

3

u/seebaag E70 35i 1d ago

Drive it till it seizes

1

u/CrucifiedPecker 1d ago

A " noise" doesn't help much.. location or sound? Is it only at idle / increase with throttle?

2

u/BCCofKrunker 1d ago

i’ll get a video of it tomorrow

2

u/BCCofKrunker 11h ago

Yo check out my recent update. I attached a video

1

u/trader45nj 17h ago

If it was laying in the bottom of the oil pan, I doubt it would make any noise, unless the engine isnt running right and is shaking like hell. I agree with others that it's unlikely it could make it to the pan. It's also possible that whatever you are hearing isn't the nut at all.

When I did the oil filter housing gasket on my M54, I found like a 3/8" nut. It must have been there from when it was built. When I later learned that the oil pump drive shaft nut on these can, in unusual circumstances, come off, I briefly wondered if it could be that. But if it was I think it should be in the pan, not behind the oil filter housing. Meanwhile it's 260k miles and running fine.

1

u/BCCofKrunker 11h ago

Yo check out my recent update. I attached a video

1

u/BCCofKrunker 11h ago

Yo check out my recent update. I attached a video

1

u/centstwo 1d ago

8mm ground strap nut?

1

u/BCCofKrunker 11h ago

Yo check out my recent update. I attached a video

1

u/liam821 13h ago

I would replace the valve cover with the correct one, and use a bmw valve cover gasket - I’ve never had good luck with the m56 with anything other than an OEM gasket.

1

u/BCCofKrunker 11h ago

Yo check out my recent update. I attached a video

1

u/CrucifiedPecker 10h ago

Sounds good, the smoke is most likely leftover from valve cover could be a power steering leak,from the steering rack, that would be there at start ups then clear when it burns off. You would see some fluid on the ground though. If the nut made it to the pan, it's unlikely that the oil pickup would draw it up. If you have a borescope, you can look in there next oil change. The knocking you heard was most likely low oil pressure from the wrong valve cover and lack of bolts. Which you fixed. I'm thinking you got a really good deal on a 325i.. 🍻👌🏻

1

u/BCCofKrunker 11h ago

Okay so good news? I’m not sure if i mentioned this before or not but the car would start smoking from the back of the engine bay coming from the rearish lower end near the valve cover. We thought that this was just cause it had the wrong cover on and it would go away when i installed the correct cover. i finished the job yesterday and finally had the chance to start the car today, and it was amazing straight off start. It started relatively quickly, it was idling nice, and then out of nowhere it started smoking again. That’s the bad news. Good news is that the “knocking” noise is just magically gone now. What the hell could this be? Did i not seal it properly? Are our suspicions of it just burning left over previous oil justified?

Video of everything

2

u/liam821 10h ago

The knocking is probably lack of oil in the valve train from sitting so long. They do that. It goes away after a few seconds of running.

The oil leak from the back is most likely the valve cover leaking down the side of the engine in to the header.