Any idea what this leak is?

[CitizenKane]

Firstly as with all my posts here I’m pretty clueless about this stuff so apologies if this is a stupid question.

Below are some photos of the under carriage of my 2006 318Ci taken from the front. The car has been leaking oil and coolant for a while now, but I’ve never diagnosed the source of either leak.

Do these photos give any indication of where the leak might be coming from, or does it not narrow it down at all?

Any help much appreciated.

[318 iS Cosmos]

How bad is the leak? A few spots on the ground every so often? Do you have to top up the oil and coolant regularly?

My advice would be to jack up the car, remove the under trays and clean any of the oil off the engine and then monitor


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[SmokyMo]

Could be anything. Need to remove the cover.

[CitizenKane]

How bad is the leak? A few spots on the ground every so often? Do you have to top up the oil and coolant regularly?

My advice would be to jack up the car, remove the under trays and clean any of the oil off the engine and then monitor


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It's not pumping out but it's not great, I need to top up both probably every 6 weeks or so, although the coolant top ups are getting more frequent recently.

[CitizenKane]

Could be anything. Need to remove the cover.

Hmm that's what I feared

[318 iS Cosmos]

It's not pumping out but it's not great, I need to top up both probably every 6 weeks or so, although the coolant top ups are getting more frequent recently.

Any mayo like substance under the oil cap?
The plastic trays are very easy to remove once you have access to a trolley Jack and axle stands.


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[CitizenKane]

Any mayo like substance under the oil cap?
The plastic trays are very easy to remove once you have access to a trolley Jack and axle stands.


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Nope no mayo.

I don't have access to a jack or stands unfortunately, but I feel with this car it might have been wise to invest in some!

[CitizenKane]

Interestingly I’m still getting that noise on startup which I’m pretty sure means my cam chain tensioner needs to be replaced (as per this thread: http://www.bmwhaus.ie/vbulletin/show...-this-noise-is)

I wonder if the two things are connected in some way.

[318 iS Cosmos]

Tensioners can weep oil alright, did you check the timing chain for any slack? To be honest, these cars are well known for oil leaks around the rocker cover & oil filter housing but you should be able to see these from the top of the engine.

[Dave]

Tensioners can weep oil alright, did you check the timing chain for any slack? To be honest, these cars are well known for oil leaks around the rocker cover & oil filter housing but you should be able to see these from the top of the engine.

That's a weird design, is the tensioner in an oil passage on these? Figured it would have have been behind a sealed timing cover.

I would have thought:
1. Rocker cover gasket
2. Oil filter housing gasket
3. Rear main oil seal
4. Front main oil seal
5. Sump gasket.