Low oil Pressure - N54Tech.com

Ninja_Spartan · **Low oil Pressure -** 02-20-2018, 03:21 AM

Hey Guys and Girls

After spending a lot of time looking around I could not find much info on the topic of Low oil pressure for the N54. It would appear that this is a rare issue/fault? Even the dealers I spoke to in NZ have not seen this issue and didn't offer much help.

The low oil pressure comes on when cold followed by the typical vanos faults and 3100. When the engine is warm the low oil pressure light does not come on when I turn the car on.

I have replaced the oil and filter(Castrol 5w-30). The old oil looked fine and I did not see any metallic objects. The oil changed had no effect and I still have low pressure.

From doing an oil pressure test I have the following results.
First startup (Cold) oil pressure came up to just under 1 Bar.
When the engine startup phase finished and RPM decreased to 700ish oil pressure increased to around 1.2 Bar.
When I rev'd the engine up to around 2500-3000rpm the oil pressure dropped to 0.75 Bar.

When testing on my brother's 335i during startup (warm) oil pressure was around 2 Bar at idle. When I rev'd the engine oil pressure went up to 5 Bar which is what I would expect.

I'm a little stumped on this as if it was engine wear on the cam bearings or if there was a leak I would expect the oil pressure to still increase when RPM also increased, not the other way around.

This leaves me to believe it may be a blocked oil pickup?

Currently it looks like I will be taking the sump off the car.

Additional details
There are no oil leaks.
Car has 140k KM. (86k Miles)
Car is 2009 with DCT
MHD Stage 1
Everything else is stock.
Edit: I am from New Zealand (NZ)

If anyone has any ideas to what may be the culprit let me know!!

Thanks.

Vorsprung_CJB · 02-20-2018, 10:13 AM

Failed oil pressure relief valve? There is also a pressure sensor, but if that failed I would expect no reading, unless maybe it is gummed up some how. Could be a pump or pickup issue, or some other rare issue. Let us know what you find with the pan off.

Ninja_Spartan · 02-24-2018, 04:20 AM

Update: After removing the sump I have found bits of what looks like engine serpentine belt blocking the oil pick up quite badly.

There are also some belt fragments around timing change guides.

The previous owner must have broken a belt and some has got behind the crank pulley then through the crank seal. Not sure how this has happened as there are no leaks around the seal.

Will update once it is all put back together.

Cotwell335 · 02-24-2018, 06:39 PM

Belt fragments that get sucked though the front crank seal happens everyonce in a while. You definitely need to check out the cam lobes and cam bearing caps to see if there is any damage. I’ve seen a few engines suffer severe damage from customers driving the car with very little oil being circulated throughout the engine with little pressure. Best of luck!

Ninja_Spartan · 02-24-2018, 07:00 PM

Thanks, Will check out the cams and see if they have suffered excessive wear.

Vorsprung_CJB · 02-24-2018, 07:55 PM

That shredded belt can end up in a lot of places in there. Do some research on what you need to check.

Ninja_Spartan · 04-04-2018, 03:51 AM

Update for anyone that was wanting to know.

Oil Pickup was almost completely blocked with belt fragments and there was also belt fragments around the timing gear. At the bottom of the sump there was a large amount of metal shavings both aluminum color and what looked like a copper/bronze color.

The Engine has been removed and will be dissembled. Hopefully it can be rebuilt if crank and cams are okay.

Vorsprung_CJB · 04-04-2018, 08:20 AM

Wow sucks that the previous owner didn't disclose that. How long has your brother had the car since then?

Ninja_Spartan · 04-07-2018, 04:13 AM

Yep, it sure does suck. I have a feeling the conrods are damaged and possibly the piston pins will be scored. But on the plus side it gives me an excuse to do a built engine.

My Brother has had his 335i for over a year now and he has had no issues with his. Lucky bastard.

Boland01 · 04-07-2018, 05:45 AM

Thank you for the update and sorry this happened. Years back on our E36 one of the cam chain plastic guides disintegrated, blocked up the oil pump and had the same result with the car as you did.

We ended up rebuilding the motor and had to put in a new crank and exhaust camshaft. Once metal fragments get into the engine they will literally go everywhere.

DaveLyd · 06-10-2019, 08:10 PM

Do you have an update on what the outcome of this was? I bought an E70 with the N55 engine a couple of weeks ago with a knock in the engine above 2000 RPM, and found what I now know to be belt material under the valve cover and around the timing chain.

The last project was an E28 535i with a blown head gasket / shredded clutch, and last year I replaced the M52 engine on my teenage son's E39 wagon after he overheated it (in between replacing synchromesh's on my '72 MGB), so I don't mind doing a bit of work, and am in no great hurry - but I'd love to know what ended up happening with your project.