Smoking engine

Hey guys n girls, I'm pretty new to the whole bmw thing so please be patient.

For some unknown reason I am occasionally getting a burning smell coming from the engine bay of my 325. Sometimes when I open the hood I see a little bit of smoke coming out of the plastic cover on top if the engine, sometimes there is no smell and no smoke...

Does anybody know what could be causing this? Doesn't appear to be leaking any oil anywhere so has me pretty confused!

Looking forward to your replies

Brodie

Originally Posted by Brodie325i

Hey guys n girls, I'm pretty new to the whole bmw thing so please be patient.

For some unknown reason I am occasionally getting a burning smell coming from the engine bay of my 325. Sometimes when I open the hood I see a little bit of smoke coming out of the plastic cover on top if the engine, sometimes there is no smell and no smoke...

Does anybody know what could be causing this? Doesn't appear to be leaking any oil anywhere so has me pretty confused!

Looking forward to your replies

Brodie

Well there has the be something on the engine that is causing this. A leaking VCG (valve cover gasket) will put oil on the side of the engine and it tends to smoke I believe. Did you check the sides of the engine and the plastic under cover? If the oil leak is small there won't be any oil dripping under the car, it will all stay in the plastic cover. When it is cool, put your hand on the sides and back side of the engine block to see if you get any oil on it. Also, take the bottom plastic cover off with a phillips screw driver and inspect it for oil drops.

If coolant is leaking, then you need to check your hoses and coolant level. If that's below minimum, then you may have a leak.

Thanks heaps for the info, I know it ain't a coolant issue so ill take the cover off and look for the oil spots, was just reading another post it sounds like the valve cover gasket...

Is this something that will cause major damage if I keep driving it?

Originally Posted by Brodie325i

Is this something that will cause major damage if I keep driving it?

Not so long as you don't let it get low on oil. Just keep an eye on the dipstick until you have a chance to fix it. Many E46 owners either are in your position, or they're about to be.

Originally Posted by Wolrab

Not so long as you don't let it get low on oil. Just keep an eye on the dipstick until you have a chance to fix it. Many E46 owners either are in your position, or they're about to be.

+1. It's not critical, but you should replace the valve cover gasket when you get the opportunity. If you are slightly handy you can do it yourself with no real special tools except a small inch*pound torque wrench, spark plug socket (in your car's trunk toolkit), and a couple other common tools. Keep a few quarts of LL-01 oil around to top off if the level gets low.

There are tons of members on this forums who have replaced their VCG with success, and many who made mistakes and posted them so you can learn what to look out for/what not to do (hint: don't try to do this without a torque wrench). Read about it until you're exhausted of it, then read some more. Then do the replacement yourself. While you are under the valve cover, I think it's also a good opportunity to replace the VANOS seals too, even if they seem okay. It'll save you time down the road and you won't have to buy a new VCG again.

You are describing a valve cover gasket that is leaking. This is a common ailment. Small amounts of oil can drip onto the exhaust manifold and this makes smoke. Sometimes the smoke is heavier than other times.

The oil that's coming out is not under pressure, so it isn't spraying out it is just dripping. Oil is pumped under pressure to the top of the motor where it then flows by gravity to the bottom and begins the journey over again. Your leak comes from oil that is pooling at the rear of the engine before it flows down through the many drain holes that take the oil to the oil pan.

You can have this leak for a very long time and not do any damage beyond getting serious oil stains on the side of the block/cylinder head, and the exhaust manifold. Eventually you will have oil stains on your garage floor.

Cheers for the info guys, are the vanos seal easily replaced? And where is a good place to get the seals n gaskets from?

As the guys stated it's a typical sign of a failing valve cover gasket. It's not a terrible hard diy, HERE is a link to one of the more detailed diys for you to read over. You'll need to pay attention to the build date on your car for which valve cover gasket set you need as there is a vin split in 09/2002.

For cars build before 09/2002 you need BMW part number 11129070990.

For cars build after 09/2002 you need BMW part number 11120030496.


The vanos gasket (BMW part number 11361433817) isn't terribly hard to change out. Depending on if you want to go ahead and do an anti rattle kit, change all the seals, etc it can get pretty involved. HERE is a link to a great diy and parts list for the E46 double vanos.

Originally Posted by Brodie325i

Cheers for the info guys, are the vanos seal easily replaced? And where is a good place to get the seals n gaskets from?

You can get kits from various manufacturers. Read around the forums and see what people have used with success. For the VANOS seals, many people seem to buy the Besian Systems VANOS kit. They make a seals kit and another kit that fixes a rattling noise. I would just get both.