My MX5 has done just over 159,000 miles and it doesn't appear to smoke, however it does have some black deposits on the back of the car when you wipe it over with a leather. I have to do this nearly daily as the car is parked under trees (I put a cover on overnight), so when wiping with a damp leather to get any other muck off, it gets covered in a thin layer of black muck! The last time I wiped it over was around 23 miles ago and today it has more black deposits!

Im not expecting much out of a 21 year old car with 159K on the clock, however I wondered if this was "normal" for an older petrol car!? Otherwise I guess it might be picking this muck off the road? It seems to cover the back of the car (boot, bumper and mud flaps). The car is lowered and does need to have the exhaust replaced as it has a few holes!

Cheers for any advice

How much oil are you getting through would be my first check.

If it's a little bit, then I'd check the breather system and make sure it's not gunged up as a bit of pressure there can cause oil to be forced out.

If the car is a weekend/occasional use or used for short journeys then you'll get some carbon deposits building up in the combustion chamber and exhaust system, (160k. miles can mean worn piston rings). They'll get blown out by a bit of heavy acceleration. The fuel system may also be running rich and contribute to the soot. Cheap oil and petrol don't help. If it's passing the MOT emmisions ok you don't have anything to worry about.

Thanks for the replies It doesn't appear to be using much if any oil at all Its got its MOT soon so its sure to highlight any problems. I was thinking of a de-cat (perfectly legal on a 1990 MX5) but I think I will wait until after the MOT and see what it does emissions wise.

Cheers for your help