E90 6cyl - oil leaks?

[edgesr]

Hi All,

I've had my E90 330i (N53) for a few months now and have noticed a burning smell in the cabin and a puff of white smoke coming from the top of the bonnet from time to time. I only really notice this when the engine is hot am i am in slow moving traffic. I'm thinking that at 60mph+ the smoke is blown away into the atmosphere more easily.

I took it into my specialist and they originally diagnosed nosed the rocker cover gasket as the issue - no trouble, all swapped and i was advised the smell may take a little bit of time to disappear completely. I've now done a several hundred more miles and the issue is still there. I took it back to the garage and the think it may be a plastic sheet beneath the rocker cover that has warped over time and is letting oil out.

Does anyone have the knowledge to know whether this may be the case? I can't find much on line about plastic in this area, other than the valve cover itself. I have said that I won't pay for the rocker cover gasket to be re-done, as it was the diagnosis that is wrong.

Cheers

[CB 987]

Do these have an oil filter housing gasket like the N52’s? My old N52 had it replaced before my ownership, so no idea if this would cause symptoms you’ve been experiencing.

[bmwmike]

I'd find another garage for a second opinion unless you are willing to poke around under bonnet to.

In short it's a typical BMW engine so they will leak like an old bucket at some stage, sooner than you expect though.

Common ones I know about.

Valve covers can crack by cylinder 3.
Valve cover can leak onto exhaust nr cylinder 6 usually.
Oil filler housing gasket.
Rear main seal at higher mileage.

No idea what the sheet you refer to is.

[edgesr]

bmwmike said:

I

Valve covers can crack by cylinder 3.
Valve cover can leak onto exhaust nr cylinder 6 usually.
Oil filler housing gasket.
Rear main seal at higher mileage.

No idea what the sheet you refer to is.

Thanks for that, he may have meant the valve cover and poking around that's the only thing i can see it being. He did mention they get a similar issue with the automatic gearboxes of the same age, plastic warps from all the hot and cold cycles. Your 2nd suggestion could be it, it's definitely near cylinder 6, the smoke rises up near the windscreen on drivers side, almost certainly dripping onto the manifold.

I didn't really have the time to question him properly, was rushing off to work straight after the diagnosis. It's on 80k, so not too high.

[davejf]

edgesr said:

Hi All,

I've had my E90 330i (N53) for a few months now and have noticed a burning smell in the cabin and a puff of white smoke coming from the top of the bonnet from time to time. I only really notice this when the engine is hot am i am in slow moving traffic. I'm thinking that at 60mph+ the smoke is blown away into the atmosphere more easily.

I took it into my specialist and they originally diagnosed nosed the rocker cover gasket as the issue - no trouble, all swapped and i was advised the smell may take a little bit of time to disappear completely. I've now done a several hundred more miles and the issue is still there. I took it back to the garage and the think it may be a plastic sheet beneath the rocker cover that has warped over time and is letting oil out.

Does anyone have the knowledge to know whether this may be the case? I can't find much on line about plastic in this area, other than the valve cover itself. I have said that I won't pay for the rocker cover gasket to be re-done, as it was the diagnosis that is wrong.

Cheers

I’ve had similar for the last 12 months. E92 330i. It came through the vents when the heating was on over the winter. I took the cover off and found it pooled in the plug holes between 3&4. On hard left cornering it would come over and drop onto the manifold creating the smoke.

As the water pump failed on Saturday I dropped it in to the local Indy yesterday evening and asked them to look at that too as I had hoped it might be the valvetronic gasket (cylinder that sits between 3&4) but they’ve come back and said it’s a cracked rocker cover.

If yours is leaking around 6 then it could well be the rocker cover. Shouldn’t be filter as that’s the opposite side of the engine to be dropping on exhaust.

Good luck and I hope it’s not too expensive as mine is proving to be right now!

[willc68]

Just another suggestion, I’d check for oil seeping out of the oil fill cap, might be easier to spot the oil leaking from this area if you remove the plastic acoustic/aesthetic covering. Around the oil fill cap there’s a rubber gasket which gets a bit ropey after a while. As the engines are mounted at an angle the seeping oil runs down the engine cover and onto the exhaust manifold creating the burning smell.

The trick I used was to take the gasket off, clean it up (wd-40 was the suggestion I think) and then importantly reverse it. For whatever reason this then provided enough of a seal for it to stop seeping. Beyond that they can’t be that expensive to replace and worth a shot if the signs point to it being the culprit

[edgesr]

davejf said:

I’ve had similar for the last 12 months. E92 330i. It came through the vents when the heating was on over the winter. I took the cover off and found it pooled in the plug holes between 3&4. On hard left cornering it would come over and drop onto the manifold creating the smoke.

As the water pump failed on Saturday I dropped it in to the local Indy yesterday evening and asked them to look at that too as I had hoped it might be the valvetronic gasket (cylinder that sits between 3&4) but they’ve come back and said it’s a cracked rocker cover.

If yours is leaking around 6 then it could well be the rocker cover. Shouldn’t be filter as that’s the opposite side of the engine to be dropping on exhaust.

Good luck and I hope it’s not too expensive as mine is proving to be right now!

Sounds similar to my issue, I really hope it isn't the cover itself. I only notice the burning when stationary or extremely slow traffic. The only thing I can see being plastic is the CVV which could in theory warp. Got it booked in with Forza Monday so we shall see!

[Biden]

Old one, but what was the issue in the end?

I have similar in my N53 just now... going to redo the PCV tomorrow, but guessing its either gasket or valve cover that's causing this issue.