Instant Low Oil Pressure... Oil Pump Nut?

[seagreen323i]

Dad was driving and said it looked like the car from James bond.

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[MaxVQ]

Thanks to Black Friday sales, it tool almost 2 weeks to get the parts (oil pan gasket + o-ring and power steering pulley)

All bolts are cleaned, as well as engine/oil pan mating surfaces.
I drilled and safety wired the oil pump nut to the sprocket, so this won't be a problem again.

Tonight I hope to get the oil pan on... It is slow progress as I am doing this on my back, with my car on jackstands.
To minimize what needs to be disconnected from the subframe, it is only lowered and not slid out.
This means it is always in my way and I need to reach around / through it to do anything.

Also, I re-timed how long I drove it without oil pressure....it was close to 3 minutes!!
I think the start up will be interesting!!

[philly98540]

Good to use a quality torque wrench when tightening the oil pump nut and tighten to proper spec. My 540 oil pump shaft sheared in two like 8 or 10 years ago directly behind the nut. The oil pump shaft has a reduced diameter directly behind the nut and before the sprocket splines. I believe I must have overtightened it and the stress was too much for that part of the shaft. I think all the BMW pumps are like this. I used a torque wrench when I put it on when doing my guides, but it was not a great torque wrench. I've since upgraded my wrench. When mine broke, it was years after doing the guide job and I was in the garage during a cold start. The light came on and I turned the engine off immediately. I then dropped the pan and found the issue.

[SW530]

Today I dropped the subframe and oil pan.
The nut did fall off and was found in the oil pan!

With a new oil pan gasket and a little loctite red, it will be back on the road

And to think how lucky you were to find the old nut, now you don't have to buy a new one..

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[MaxVQ]

Good to use a quality torque wrench when tightening the oil pump nut and tighten to proper spec. My 540 oil pump shaft sheared in two like 8 or 10 years ago directly behind the nut. The oil pump shaft has a reduced diameter directly behind the nut and before the sprocket splines. I believe I must have overtightened it and the stress was too much for that part of the shaft. I think all the BMW pumps are like this. I used a torque wrench when I put it on when doing my guides, but it was not a great torque wrench. I've since upgraded my wrench. When mine broke, it was years after doing the guide job and I was in the garage during a cold start. The light came on and I turned the engine off immediately. I then dropped the pan and found the issue.

Thank you for the tip. I did use a good torque wrench and will hope for the best

[MaxVQ]

And to think how lucky you were to find the old nut, now you don't have to buy a new one..

I had that thought... but it had to be in the oil pan, as it couldn't be anywhere else

[MaxVQ]

Oil pan is on and torqued. That isn't easy to do by yourself with the car on jack stands!
Tomorrow I will start to bolt up the subframe.

[SW530]

I had that thought... but it had to be in the oil pan, as it couldn't be anywhere else

I was thinking more along the lines of I'd much rather have a nut with new threads as they would be more likely to fit better. The nut found in the oil pan has already came off for whatever reason. One of those reasons might have been a poor fit to start with. The nut was also bouncing around in there for a while not to mention it has a lot of miles on it. A new properly fit nut would ease my mind a lot.

Also, when it comes to loctite.. the selection of what loctite is vital. Some types "fill" space to a certain degree, so you want to get the loctite best for your application. And for sure you'll want to use a primer and like the product itself, there are different primers for different uses. This is a good general purpose primer but there are 7-8 different primers and it might be worth the effort select the best one for your application.

One more thing: Loctite products have an expiration date.. My experience is you don't want to exceed that date by very much.

I do a lot of gunsmithing/gun building/etc.. and it took me a while to become a believer, but having a customers whatever fall off in the middle of a competition tends to make a believer out of you.. But now I have a small plastic toolbox with various products that I keep track of, etc, to make sure I use the right products.

[MaxVQ]

I was thinking more along the lines of I'd much rather have a nut with new threads as they would be more likely to fit better. The nut found in the oil pan has already came off for whatever reason. One of those reasons might have been a poor fit to start with. The nut was also bouncing around in there for a while not to mention it has a lot of miles on it. A new properly fit nut would ease my mind a lot.

Also, when it comes to loctite.. the selection of what loctite is vital. Some types "fill" space to a certain degree, so you want to get the loctite best for your application. And for sure you'll want to use a primer and like the product itself, there are different primers for different uses. This is a good general purpose primer but there are 7-8 different primers and it might be worth the effort select the best one for your application.

One more thing: Loctite products have an expiration date.. My experience is you don't want to exceed that date by very much.

I do a lot of gunsmithing/gun building/etc.. and it took me a while to become a believer, but having a customers whatever fall off in the middle of a competition tends to make a believer out of you.. But now I have a small plastic toolbox with various products that I keep track of, etc, to make sure I use the right products.

Thanks for the info/tips.

I decided not to use loctite, even though I just bought some for this.
Instead, I drilled the nut and safety wired it. I like the idea of me being able to easily remove it, if required.

[ross1]

Three minutes is a long time to be running without lubrication. Will be a dry start too on top of all the other abuse/miles unless you prime it.
My advice would be to pull the plugs and spin it with the starter until pressure builds enough to turn out the warning light, rest the starter and crank it a while longer to try and get some up to the valvetrain which is the asshole of the oiling system.
Good luck, fingers crossed for you.

[MaxVQ]

Good advice, but with my garage being 4C/40F, I'm doing everything I can to get it done quickly... The engine oil is warming up in my house, I'm going to pour it in and start it. An extra 5 seconds of no oil pressure won't make any difference. If there is damage, it is already done.

[ross1]

Good advice, but with my garage being 4C/40F, I'm doing everything I can to get it done quickly... The engine oil is warming up in my house, I'm going to pour it in and start it. An extra 5 seconds of no oil pressure won't make any difference. If there is damage, it is already done.

Do yourself a favor. If you won't remove the plugs at least crank it with the fuel pump disabled until the light goes out. The last thing your bearings need now is a dry start.

[seagreen323i]

That's like saying "my ankle is already broken from jumping off of this let's do it one more time" prime the engine lol

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[MaxVQ]

Ideally, I should crank the engine over before starting, but I'm not going to.
At this point it is just like an oil change and it will take 2-3 seconds to build pressure.

Before this happened, I was deciding to scrap the car or fix it up. It has 260,000 miles on it, lots of rust on the body and one of the rear factory jack points have rusted away.

My prediction is that everything will be good... then I will consider spending $10,000+ on body repair and paint to make it almost like new.
AND if I decide to do that, the engine is due for a rebuild anyway.

Tonight I will bolt up the front subframe and the other required items to be able to start the engine.

I do appreciate everyone's input and you are all right about what should be done.
I've been working on cars for 40+ years and I am doing a test to see what happens if I do everything I wouldn't normally do.

[KeysCoupe]

Its not like a start-up after an oil change. When doing an oil change, the system is still primed and mostly full of oil. Your car, on the other hand, lost oil pressure, and pumped most of the oil out of the system. It will take a bit more cranking to catch prime and fill the galleys.
If it were me, I’d be cranking over the engine with the fuel pump disabled until the oil light goes out from pressure. Then try to fire it up.
It sounds like you just want to roll the dice by not following good advice.
-Donny

[MaxVQ]

Its not like a start-up after an oil change. When doing an oil change, the system is still primed and mostly full of oil. Your car, on the other hand, lost oil pressure, and pumped most of the oil out of the system.
-Donny

How is the system still primed? When changing the oil, all of it drains out of the oil tube pick up and partly out of the oil pump, as well as oil the filter.
As for "pumped out of the system" how does that happen when the oil pump has stopped turning?

Again, before this happened I was thinking of scrapping the car due to high milage, leaks and rust.
If I am wrong about the engine being OK, then the decision is made.
If all is OK, then we can all learn about how durable the wonderful M54 is.

If you watch a few videos on Youtube of engines being run without oil, you will see that at wide open throttle they do live for a few minutes or longer.
I was mostly coasting at idle with a bit of 2,000 RPM to keep moving.

Think of it this way, instead of following the normal/proper methods, we can learn what happens if we don't.

[sleuth255]

I'm just wondering why you don't just pull the fuel pump fuse and crank it until the oil pressure light goes out first. Its so easy to do. I believe F22 and F31 in the glovebox are all you need to pull. Easy PM FTW I say with no downsides, especially after having done all that work to fix the oil pump nut first...

[ross1]

How is the system still primed? When changing the oil, all of it drains out of the oil tube pick up and partly out of the oil pump, as well as oil the filter.
As for "pumped out of the system" how does that happen when the oil pump has stopped turning?

Again, before this happened I was thinking of scrapping the car due to high milage, leaks and rust.
If I am wrong about the engine being OK, then the decision is made.
If all is OK, then we can all learn about how durable the wonderful M54 is.

If you watch a few videos on Youtube of engines being run without oil, you will see that at wide open throttle they do live for a few minutes or longer.
I was mostly coasting at idle with a bit of 2,000 RPM to keep moving.

Think of it this way, instead of following the normal/proper methods, we can learn what happens if we don't.

The oil was flung out of the bearings by the crank's rotation, not to mention a wee bit of pressure offered by the con rods, lifters bled down from being compressed, the cam journals which run in bare aluminum would have lost oiling too.
Seems like you are trying to convince yourself and others here that running it without oil pressure did no harm. Perhaps you are right but I think you are a fool not to spend a few moments that could potentially save the engine rather than prove your point, or not.
Good luck, I'm outa here
Oh, if it blows up there is another guy here who can rebuild it in situ.

[JimLev]

[SW530]

+1 Could you at least run a video of the process for our curious minds..

[sleuth255]

+1 Could you at least run a video of the process for our curious minds..

Same please! I have an M54 in my car too and I'm very interested to see how it goes.

[SW530]

Same please! I have an M54 in my car too and I'm very interested to see how it goes.

He could market a pay per view..

[MaxVQ]

Seems like you are trying to convince yourself and others here that running it without oil pressure did no harm. Perhaps you are right but I think you are a fool not to spend a few moments that could potentially save the engine rather than prove your point, or not.
Good luck, I'm outa here
Oh, if it blows up there is another guy here who can rebuild it in situ.

I'm sure there is some additional wear, but not enough to make a difference or to hurt engine life. Time will tell.

Just because I have my own theory and don't take your advice, doesn't mean you have to walk away and say "I'm outa here"

Your advice has been spot on, but like I said, since this engine has 260,000 miles on it, I'm going to do what I normally don't do, see what happens and learn from it.

[MaxVQ]

Yesterday was the moment of truth!

Everything is bolted back up and double checked.
I didn't prime the engine, as this is no different than an oil change.

The engine started right up and the oil pressure light was off in 2 seconds, just like a normal oil change.

There was no rod knock, but the valvetrain way much louder than normal. I suspect this is due to the lifters needing some time to fill with oil. Driving with no oil pressure would of pumped it all out.

After 5 minutes of idling, the valve train was about 50% quieter and I went for a 10 minute drive.
No abnormal engine vibration, good throttle response and no knocking at wide open throttle and shifting at 6500 RPM.

At the end of the 10 minute drive, the valvetrain noise is back to normal, with just a little of the normal tick from the fuel injectors and valvetrain.
As with many things, time will tell if all is ok.

I wish to thank Castrol 5W40 Edge Synethetic oil (BMW Longlife 01 approved) for a job well done.

With this said, isn't it nice to know, if you have to drive your sweet six E39 for 1-2 minutes without oil pressure to pull over somewhere safe, you probably haven't killed your engine.

[ross1]

Yesterday was the moment of truth!

Everything is bolted back up and double checked.
I didn't prime the engine, as this is no different than an oil change.

The engine started right up and the oil pressure light was off in 2 seconds, just like a normal oil change.

There was no rod knock, but the valvetrain way much louder than normal. I suspect this is due to the lifters needing some time to fill with oil. Driving with no oil pressure would of pumped it all out.

After 5 minutes of idling, the valve train was about 50% quieter and I went for a 10 minute drive.
No abnormal engine vibration, good throttle response and no knocking at wide open throttle and shifting at 6500 RPM.

At the end of the 10 minute drive, the valvetrain noise is back to normal, with just a little of the normal tick from the fuel injectors and valvetrain.
As with many things, time will tell if all is ok.

I wish to thank Castrol 5W40 Edge Synethetic oil (BMW Longlife 01 approved) for a job well done.

With this said, isn't it nice to know, if you have to drive your sweet six E39 for 1-2 minutes without oil pressure to pull over somewhere safe, you probably haven't killed your engine.

Glad its okay