My '91 940 SE burns a quart of oil every 500 miles. It runs well and ,as far as I can tell, does not blow blue smoke through the exhaust. However, it seems to leak a minimal amount of oil . Is there anything I can do to lower the oil consumption? Should I worry --the car has 150,000 miles. Thanks for your comments.

One quart in 500 miles is alot. Are you sure you don't have a cam seal or crank seal leaking? I have a 100K on my 940 SE and it uses one quart in 5000 miles.

I should have mentioned that the car recently passed the emissions test in Ontario comfortably. I don't know if this is relevant . Thanks for your advice.

It's better to pull out the plugs and see if they are clean.

It they are fouled, then you are burning oil, otherwise you have got a leak.

Have you checked to see if there is excessive crankcase presssure? You might want to see if the flame trap has been cleaned/replaced recently....it would show up as leaking oil from some point. If you have a turbo the seals on the turbo could be on their way out....theck the intercooler hoses for an oily residue to check

Whatever you do, dont add those engine additives to try and help...they'll do more harm than good IMHO