Practically Classics Forum

I have been having a problem with my 124 merc.Its a 3lt six and it has a smoking habit.It will puff away every now and again when stuck in traffic or at idle but not all the time.Last year I was stuck on the M5 and it smoked most of the oil out of the sump but other times it will run happily for months without a problem.It passed the mot the last two years with no emmission problems but two weeks after the last it started to smoke again.Is there a breather or valve that i'm missing out on???? I thourght it was the head gasket but it uses hardly any oil and the water never goes down or any emulsion.Ahy ideas other than nicotene patches?

Worn valve guides or hardened inlet valve stem seals probably, does it also smoke going down long hills or on the overun
Worn rings/bores usually show up as high oil consumption and crankcase compression i.e. fumes from the breather and possibly oil leaks.
Don't know wether the 123 6 has stem seals but the good news is they can sometimes be changed without removing the head, using the rope trick.
Look up in PC archives from last years mags on how to do this

When I had my S124, I found the guys over at www.mbclub.co.uk to be an invaluable source of information & support - not to mention occasional cheap bits Might be worth a look...

DILWEBLEY wrote:I have been having a problem with my 124 merc....Last year I was stuck on the M5 and it smoked most of the oil out of the sump but other times it will run happily for months without a problem... I thourght it was the head gasket but it uses hardly any oil and the water never goes down

You're contradicting yourself here. Is it actually using a lot of oil, or is it just smoking? If it's smoking but not using oil, you may be sucking in brake fluid into the vacuum system through the brake booster (or servo in British English). This may be caused by a leaky master cylinder and sucking in a hydraulic oil like brake fluid will cause your car to smoke up a storm.

If you're valve seals are leaky, you'll notice a puff of smoke mostly upon start up. If you're seeing it all the time, then you should expect to be burning a lot of oil.