M20 320i Oil leak from upper front of engine with photos

[MatBiscuits]

Hi all, I have a 320i coupe with just 74k miles which has this fairly persistent oil leak, runs perfect and looses very little... a drip or two every 24hrs, but I would really like to get it sorted as everything else is spot on.

I have cleaned it all down now but just hoping someone may be able to suggest where I could start looking, the main engine gaskets look fine and the filters not leaking, it looks to be coming from the front upper engine block area just in front of the exhaust manifold?

Any suggestions greatly appreciated, thank you in advance.

[dworthy]

Welcome to the Forum!

Typical places for a leak like that are in this order:

Valve cover
Rocker shaft seals
Camshaft seal

Pull off the dizzy and look behind it to check for leaks.

[82eye]

yup those are the three that would do it. dig down to the camshaft seal and replace the other two on the way.

[MatBiscuits]

yup those are the three that would do it. dig down to the camshaft seal and replace the other two on the way.

Welcome to the Forum!

Typical places for a leak like that are in this order:

Valve cover
Rocker shaft seals
Camshaft seal

Pull off the dizzy and look behind it to check for leaks.

Excellent, thank you both for the replies :-) I have removed the splash guard tray and spent the day degreasing and cleaning so the block and head are clean now.

I've ordered some UV dye and a black light torch so hopefully I'll get to the bottom of it. It looks like there is already a bit if seepage around the front corner where the block meets the head so probably going to need a new head gasket too.

[richardodn]

Excellent, thank you both for the replies :-) I have removed the splash guard tray and spent the day degreasing and cleaning so the block and head are clean now.

I've ordered some UV dye and a black light torch so hopefully I'll get to the bottom of it. It looks like there is already a bit if seepage around the front corner where the block meets the head so probably going to need a new head gasket too.

That's probably just oil from above that's dripped down and seeped along the seam. The most likely spot for a head gasket oil leak is on the exhaust side of the engine between the #3 and 4 cylinders. It'll look like a slightly dirtier area dripping down the side of the block.

[digger]

my guess is the valve cover, but while you are there the D bungs should be replaced all quite cheap and simple. if that doesnt cure it then wait for the next TB to invesigate further if its a small leak.

when doing the VC gasket check the rocker shaft lock is seated correctly as the VC can get hung up. i use a very light skim of non hardening aviation cement on the gasket and a bit of black RTV on the D bungs Also use a torque wrench to torque the nuts and check them a few times after heat cycling a few times as the gasket relaxes and bolts loses some tension

[Yahweh]

After you reseal the whole motor try some RTV (Grey Right Stuff) on that top M6 bolt holding timing cover on going into cylinder head.

[MatBiscuits]

Just wanted to report back and say thanks for all the guidance, turned out there was three leak locations haha! The dye worked a treat, rocker cover, front cam seal and the bottom oil pressure sensor. All stripped down, cleaned up, I fitted a new timing belt, water pump, cam seal, rocker gasket, thermostat, belts, oil and filter change, spark plugs and D plugs.

Now absolutely spot on, a week of running and not a single leak... hurrah! Thanks again.