[EddyC01]

Hi All,

I am new to the forum after just picking up an 07 330i. Having left the car parked up all week when I took it out of the garage today there was some oil on the floor probably about 2 table spoons worth. It felt and smelt like engine oil and was very clean. The previous owner said the car doesn't use oil and he hasn't noticed it leaking before and the oil level is showing a 3 bars so just above half way, which I will keep a very close eye on.

Ideas on what it might be and potential cost would be welcome (just deciding if I will take out an extended warranty or not, and this would suggest doing so is a good idea).

The car is a late 2007 N53 330i M Sport auto, and covered 48K.

The leak is coming out just behind the front wheels in the centre as can be seen in the pictures. I have checked the engine bay and it looks very clean and dry in there so thinking it's unlikely to be the oil filter gasket. Could it be the oil pan gasket or maybe something else? Any ideas of cost of repair would be welcome!

[Mastermixlee]

Most common issue for oil leaks is the mechatronic sealing sleeve on the auto gearbox... most often leaks and runs along the plastic trimming making it seem like it comes from elsewhere.

This may not be the case for you, but it's definitely the first place I'd look.

Have had the issue myself and it's a relatively easy DIY

[Phil325i]

Impossible to tell from your pics. You need to get it up on a ramp and probably remove the plastic undertray.

[old grey steve]

Difficult to say from the pics(not your fault of course)but the 325i's leak oil from several places.

You've ruled out in theory the oil filter hoiusing: Don't, the oil from the housing(gasket to block)leaks down from right to left along the front then makes its way from the drivers side front of the engine slowly down the length of the engine then drips down over time coating the rear quarter of the block then drips down on to the covers. This issue also effects the N54 as well. Below is a combined orcker cover/oil filter housing leak

ic

Rocker cover gaskets usually leak on the off side rear 3rd half area again oil drops down on to the covers. If you find a rocker gasket issue ensure you get the plugs leaves as well BMW sell these seperatly so you actually have to ask, below is a picture of an oil leak due to a rocker cover gasket issue.



Also on the rocker cover gasket side though rare don't ignore a cracked rocker cover they are made of plastic and I've seen the odd one mainly on the N52 with issues(picture below is of an N54 cracked rocker cover-mine to be precise)they show their hand when the engine warms up as plastic expands the crack then opens up.



We've seen few vac pump issues again oil leaks are from the rear so you'd see oil in the same region.

You'd expect the obvious one to be a sump gasket, having seen loads of the N52/53 engines in our workshop these I have to say re leaking aren't that common, we have however seen leaking sump plugs or rounded leaking plugs due to previous oil changes/ham fisted previous work, usually with this in tow if it's found to be the case best option is oversized plug and you'll be helicoilingbthe sump, not ideal but it's the best route fix. Again on the sump also seen oil level sensor leaks if this is the case simple enough to sort out the sensors around £124+VAT if your cars level sensor has a fault(fairly common)then you've killed 2 birds with 1 stone

We've also seen on the odd occasion the breather pipes saturated in oil(breathers on these are on the near side under and around the manifold area)oil Coates these and air flow etc can push the flow backwards and downwards again coating the under trays as time goes, but I'd say this ones a rank outsider.

Honest option is to get the car inspected in the air covers off if there's too much oil under there coating the block then the first look may be inconclusive, if this was the case the way forward would be to have the underside chemically cleaned and re gist the leak after a few days driving, you'll immediately be able to spot the emergence of fresh oil.

Re the gearbox and the sleeve sure they leak and you may well if yours is an auto have a leak(seen loads)the leaks with these generally seem to coat the plastic sump and as the leak from the plug on the right hand side and air flow pushes the fluid back any oil from the plug will sit on the fins of the gearbox sump or will eventually sits on the gearbox sump cover which is entirely separate to the engine covers so based just on your picture I'd say, sure you could have a gearbox sump,leak, but your pictures if say point towards engine esq. issues. Below is a picture or 2 of a gear box sump notice how the oil clings to the plastic sump






picture below shows the sump this time cover on and you can see the small accumulation of oil staining on the gearbox sump cover, but this is further back than you r picture seems to indicate(but if you have an auto don't rule it out)




Hope this helps

[EddyC01]

Thanks for the replies everyone, great information! and Wo Steve an awesome answer, thank you so much!!!!

I think I will take your advice and get her into a garage pronto, sounds like none of them are major fixes so I will use my trusty local indi.

From the reading I have done it doesn't sound like I need to be overly concerned, I have to nip some friends to the airport tomorrow (40 miles round trip) sounds like I should be ok to make that without causing any damage.

[old grey steve]

Originally Posted by EddyC01

Thanks for the replies everyone, great information! and Wo Steve an awesome answer, thank you so much!!!!

I think I will take your advice and get her into a garage pronto, sounds like none of them are major fixes so I will use my trusty local indi.

From the reading I have done it doesn't sound like I need to be overly concerned, I have to nip some friends to the airport tomorrow (40 miles round trip) sounds like I should be ok to make that without causing any damage.

Its honestly all you can do never assume anything but if its leaking and you've not got Ray Charles giving it a once over these cars aren't bad at all at finding the issue