2002 E46 320i - I have a small oil leak, what is this nut for?

[scottr 11]

Hi All, hoping someone will be able to help me here. I seem to have developed a small oil leak, and i have no idea what the nut it's leaking from is for.

I drove in the gate today after a bout of 1st birthday shopping and noticed the car smelt a bit funny, almost like electrical burning. Then after parking in the garage noticed smoke coming out of the drivers side of the bonnet. Suspecting an eletrical fire I immediately backed out of the garage away from the house and jumped out. No fire ensued (yay!), and after further inspection (after removing a headlight) I'd found small portions of gritty looking oil over the cam pulse generator, the tube thing beneath it (I can't seem to find out what it is, but it had a plug at the end of it) and gritty drip marks over the radiator hose, which is under the tube thing.

Now I think the smell and smoking was a combination of oil + radiator hose as nothing looked melted and nothing started smoking after i'd let the car run for a bit. The engine bay's fairly clean, except for the area around the leak point. It looked like it had been accumulating for a bit (there's not a great deal there, but it looked like it was fairly old) so I think it finally reached critical mass.

I gave the area a bit of a clean and ran it for a while to see if I could find a leak. I found a nut on the head that developed a small amount of clean oil on it, but wasn't convinced that it was coming out of the nut (it was just a nut attached to the head that didn't appear to be holding anything down) so gave the area a clean and tried again. I went for a drive to grab some beers (all that effort was thirsty work) and when I got back I checked again. Yup, the only new oil appeared to be seeping out of the end of this nut.

I had a look on realOEM and couldn't find much about it, does any one know what this random looking nut is for, and why it woudl be seeping oil?

Thanks!

Scott

[Greg111 13]

By the looks it is one of the nuts holding the timing chain cover, same as the nut above the cam sensor.

[scottr 11]

By the looks it is one of the nuts holding the timing chain cover, same as the nut above the cam sensor.

Hi, thanks for the reply. yeah looks like it might be part of that. The oil seems to be seeping out down the thread itself, which is a bit strange. Maybe it's not tight enough or perhaps the gasket behind it is bung. Either way i think the vanos is starting to show it's age (rough idle when starting from cold, lack of power down low, poor economy) so I might take it off and replace the all the seals at some stage over the next month or so.

Thanks for your help!

[Greg111 13]

Yes, either the nut is loose or the gasket behind the timing cover has had it. Sounds like the Vanos seals have perished also.

[Allanw 1071]

Do your rocker cover gasket when you do the Vanos - You may have a slight drip onto the exhaust from it. A radiator hose isn't hot enough to create the smoke - the exhaust is! If you're doing the work anyway, the rocker cover gasket only take about 2 minutes, as you have the cover off anyway.

[scottr 11]

Do your rocker cover gasket when you do the Vanos - You may have a slight drip onto the exhaust from it. A radiator hose isn't hot enough to create the smoke - the exhaust is! If you're doing the work anyway, the rocker cover gasket only take about 2 minutes, as you have the cover off anyway.

Yeah I will do, spent the last day reading up on how to replace the vanos seals and it doesn't look too painful, I just need to acquire more tools and some parts. Has anyone here had a go at replacing the vanos seals? I'm humming and hahing about doing the water pump while I'm there but I might just tackle one thing at a time.

I couldn't see any oil seeping out of the gasket and the exhaust looked pretty clean., the only source I could find was what appeared to be slowly coming out of that nut and dripping down onto the radiator hose and a bit onto the alternator.

[Greg111 13]

Quite a few people on here have done the seals including me, different engines have different Vanos systems so the method is different. They're not hard but if you're in doubt get someone who knows how.

[Allanw 1071]

Yeah I will do, spent the last day reading up on how to replace the vanos seals and it doesn't look too painful, I just need to acquire more tools and some parts. Has anyone here had a go at replacing the vanos seals? I'm humming and hahing about doing the water pump while I'm there but I might just tackle one thing at a time.

I did mine recently: Thread Here.

[scottr 11]

I did mine recently: Thread Here.

Awesome, good read, sounds like it was a worthwhile fix for you. I'll probably buy the fan tool though as I'm not quite keen to swing a heavy hammer around that much plastic. Will purchase bits and pieces over the next few weeks and give it a go.

[scottr 11]

Well the nut was tight enough so I took it off and gave both it and the area around where it mounts a good clean. Put it back on and went for a drive and all seems to be well. Will see how it goes over the next couple of days.

[Greg111 13]

Awesome, good read, sounds like it was a worthwhile fix for you. I'll probably buy the fan tool though as I'm not quite keen to swing a heavy hammer around that much plastic. Will purchase bits and pieces over the next few weeks and give it a go.

Putg a 32mm spanner on the viscous nut and just smack the top of the spanner with a hammer, couldn't be easier.

[hotwire 352]

Putg a 32mm spanner on the viscous nut and just smack the top of the spanner with a hammer, couldn't be easier.

Reverse thread of course

[KwS 2425]

Putg a 32mm spanner on the viscous nut and just smack the top of the spanner with a hammer, couldn't be easier.

Exactly how i did it, easy as pie.

[Greg111 13]

Reverse thread of course

Goes without saying

[scottr 11]

Goes without saying

Have ordered a 32mm spanner along with some other tools from amazon. Will be ordering the seals etc shortly. Looks like i'll be going the hammer way., couldn't bring myself to pay 30+ USD for a metal bar with two holes in it

[Allanw 1071]

Have ordered a 32mm spanner along with some other tools from amazon. Will be ordering the seals etc shortly. Looks like i'll be going the hammer way., couldn't bring myself to pay 30+ USD for a metal bar with two holes in it

If the pulley spins under the belt, get another hand to squeeze two sides of the belt, thereby tightening it - hold the pulley a bit tighter A couple of good hits will usually do it anyway. Once I had a long enough spanner, it was easy as.

[Greg111 13]

Two or three hard smacks on top (not the side) of the hammer and it'll unwind, little bit of pressure to the your right and smack.

[scottr 11]

Cheers thanks for the advice guys.,