Hello all, I have a 2006 MINI Cooper S with 70,000 miles. When I start the car after it sits for about 2 hours or more, white smoke comes out for 2 seconds. The white smoke seems to stay around for a while, so I don't think it's coolant, most likely it is oil.

I attempted to do a cylinder leakdown test for the first time. Don't know if I am doing it correctly.

I did not warm up the engine, the engine had been sitting overnight.

Results are as follow:

Cylinder 1: 30psi / 28psi
Cylinder 2: 30psi / 28psi
Cylinder 3: 30psi / 24psi (i added some oil to the cylinder, then read 30psi / 27psi
Cylinder 4: 30psi / 23psi

First, what pressure should i be using for the test ? Is 30psi enough?
Also, cylinder 1 and 2 seems like there are some oil in the cylinder... maybe from the valve stem seal failing... but when i do the leakdown test, i don't know if the oil is giving a better reading for cylinder 1 and 2. I just hear hissing from the engine on all 4 cylinders... I can't decipher is air is coming out of the valve stem seal...

Any suggestions?

Any help on how to diagnose?

 

Yes #4 looks like too much, how long was your test time? Did you do a "warm" compression test as well?

 

I didn't do a "warm"compression test. The car otherwise runs fine except the startup white smoke.

Thanks for all the info on this forum, I replaced all the valve stem seals and now no more smoking on startup. The whole job took me about 2 hours to take of valve cover and replace all the valve stem seals. Here are some images of how I did the job.

The hardest part was tapping the valve to loosen the retainers. I was afraid to drop the valve into the cylinder. I did have air pressurizing the cylinder so that made the job a little easier.

Hope these images help those who might want to tackle the job!