I know i have a slight misfire on my 8 and believe one of my coils is leaking.

What coils are the best
Bosch

Bremi

Beru (i have one of these its square from the top)

and does it matter if i mix coils?
:D

Shouldn't matter, since ALL of these manufacturers supply OEM parts for BMW. Personally, I would not swap out just one coil, it is very likely that all of them are starting to do the same thing. Better safe than doing that job over and over and over again.

Just my 8 cents worth

Hi thanks for advise i was thinking of testing each coil in my 328 first or connect it to a dianostic. I do have a beru coil but its different from the originals however is for the a m62 engine

It is not very hard at all to check out your coil packs visually. Just take off the covers on each bank and each coil pack individually. It should only be two 10 mm nuts holding on the covers and then two more per coil with a lot of room to get to them. Just remember to reinstall the coils back in the order that they came out.

I had to change the coil packs on now my Mom's car because one of the boots was cracked and not working properly, which caused me to go through three sets of spark plugs before I figured it out. Damn youth and stupidity.:rolleyes I used Bavarian Auto Sport coil packs and I replaced them all just to be sure.

If you can get a good diagnostics report on the missfire, it will tell you what cylinder(s) missfired and change out that coil(s)! If you have had the covers off and found oil around the coil(s) , those would be the first suspects, If the coils are dry, they usually last a long time.

Also if you get oil around the coil boot(s) it is probably VC Gasket time. Most times the coil may be fine but the boot with the spring inside may need to be replaced.

Also if you get oil around the coil boot(s) it is probably VC Gasket time. Most times the coil may be fine but the boot with the spring inside may need to be replaced.

Good point!

Gaskets on BMW are usually one time use only unless they have less them 10K miles on them! One of my pet peeves about BMW!

I have a question for you Mwrench. I tried to send you a message but I don't think it worked. If not please send me an email.
Thanks,
P. Ford

Many thanks for the posts.

I should have joined this site earlier!

I have had the car about three months and bought it as a car to keep to restore and i knew that the covers needed replacing asap and did them myself as i am a perfectionist, i will probably do them again soon to get the covers polished and put back in.

The misfire has been there from day one, and the coils were in swimming in oil. I will sort it once the weather is better and i do have a diagnostic system to determine the problem unless i replace all them.