New here so here goes advise appreciated

[johnkent1966]

Got a 318 2004 was running ok, took it for a drive Engine light came on no power, got it scanned and multiple misfire came up, got a compression check and middle two cylinders were very low 65-70 respectively.
The car misfires badly now but doesnt overheat on the gauge.
I was thinking of tipping some engine restore down middle 2 cylinders to bring up compression, my mechanic suggested worn pistons or chain
Had the plugs out there are covered in black soot and not very clean coil packs are also ok, i have noticed when removing expansion cap there is pressure even if its cooled right down or even the next day
any ideas of what to try next
cheers

[dworthy]

Welcome to the Forum!

A compression check is just the start, you will need to have a leak-down test performed to see if it is the head gasket, leaky valve or bad rings. If it was a bad chain, it would be on all the cylinder, not just two.

[johnkent1966]

Welcome to the Forum!

A compression check is just the start, you will need to have a leak-down test performed to see if it is the head gasket, leaky valve or bad rings. If it was a bad chain, it would be on all the cylinder, not just two.

thanks for reply, do you mean low compression on all the cylinders if the chain was bad ?

I was toying with the idea of whacking some engine restore down the 2 low compression cylinders to bring them back up, its lumpy now and just about drives, is it true theres no water ways between the middle 2 cylinders as it doesnt overheat or show any signs of contamination in the expansion tank or on the dipstick, just a little on the filler cap but thats condensation

[bmwdirtracer]

Hi Darin, glad to see you again, I've missed seeing you for a while!

John, as Darin suggests, you need to do a cylinder leak down test. You should do this with all plugs out, and see whether the pressure from cylinder 2 blows out cylinder 3, and vice-versa. It seems likely that you've blown a head gasket.

[dworthy]

Thanks Chris, been working a new job and that takes a lot of my time as of late.

OP, you could attempt to put some resto down those two cylinders, but again without proper diagnostics completed, you could be wasting time/money.