engine and drivetrain Smoke coming from the engine bay

[1965ek]

Hi,

I have a -74 Tii.

Today I was trying to locate the source of an oil leak. Normally I have one drop of oil on the floor after parking the car. Finally I discovered that the oil pressure sender unit was leaking.

When doing this the car was on idle and in the sun I saw that smoke was coming from the engine somewhere. I have a big problem to locate what the source for the smoke is but at first I thought it came from the injectors. I have changed the fuel lines but using a flash light I cannot really see any leak anywhere looking at the injectors nor anything coming from the fuel lines. So this was my first thought but I cannot find anything visible telling me whats wrong. The reason for me changing the fuel lines was actually the same reason. (I saw smoke which smelled a bit like fuel)

This has now drawn my attention to the oil pressure sender unit. Could oil be dripping on the manifold creating the fuel smelling smoke? I cannot see anything dripping but I thought that maybe oil is a bit sticky and can smoke from the manifold without me seing anything dripping.

What do you think?

[SteveJ]

Yes. That is very possible. I had the same problem on our E46. The back corner of the valve cover gasket was leaking. Each drop of oil fell on the exhaust manifold and was burned off. We only smelled the oil smoke, never saw a drop on the floor.

Use some carb or brake cleaner spray to clean up all the suspected leak spots. Go for a drive and then take a look to see if there is any oil where you just cleaned.

Valve cover gasket, exhaust manifold studs, oil pressure sender, distributor shaft o-ring. All common leak spots, as well as the front timing covers & timing chain tensioner plug.

[1965ek]

Yes. That is very possible. I had the same problem on our E46. The back corner of the valve cover gasket was leaking. Each drop of oil fell on the exhaust manifold and was burned off. We only smelled the oil smoke, never saw a drop on the floor.

Use some carb or brake cleaner spray to clean up all the suspected leak spots. Go for a drive and then take a look to see if there is any oil where you just cleaned.

Valve cover gasket, exhaust manifold studs, oil pressure sender, distributor shaft o-ring. All common leak spots, as well as the front timing covers & timing chain tensioner plug.

Thank you. Oil is coming from the oil pressure sender unit. That is very obvious.

I will dismantle the sender unit and see if there are replacement parts available in the local shop. (I guess that if the thread is the same you can use a standard sender unit?)

[JohnS]

I had the same thing happen on my 73tii a long time ago. The oil leak on the pressure sender progressively got worse until it was like a Volcano bubbling out oil. That's when I figured out where the leak was. I thought I was going to have to rebuild the engine and then it turned out to be a simple and cheap replacement of the oil pressure sender. A stock replacement sender unit is around $6.00.

John

[1965ek]

I had the same thing happen on my 73tii a long time ago. The oil leak on the pressure sender progressively got worse until it was like a Volcano bubbling out oil. That's when I figured out where the leak was. I thought I was going to have to rebuild the engine and then it turned out to be a simple and cheap replacement of the oil pressure sender. A stock replacement sender unit is around $6.00.

John

That is great news John. I was a bit afraid that I would have to rebuild the engine. I have orederd the BMW specific washer closest to the head (I think it is a combination of a washer and a o-ring) but that was before I saw the leak from the oil sender unit. Did you buy a universal on or a standard oil sender unit?

[JohnS]

It was one of the standard ones that I think was made by Bosch.

Try part #61-31-1-354-274

or part #61-31-1-351-799

I think there are two different types a course threaded one and a fine threaded one. Not sure which part number is which kind. You should be able to unscrew your old one and tell which kind by looking at the threads.

[1965ek]

Thank you Sir!

A new one is ordered and willbe picked up tomorrow. Both realoem and the part store had the same thread in their books. M10*1..

I hope that I will have a completely dry car tomorrow evening.