I have a 1991 940 turbo estate which has covered 150,000 miles. Over the past year I've put in 4 litres of oil for approx 5000 miles. This seems a little excessive to me . There are no external leaks and no obvious noises from the engine. Would welcome views as to what to explore to resolve problem.
It's a fabulous motor with a cavenous rear returning approx 30 MPG when unloaded even when towing a large 2.5 ton trailer I get 20 MPG.
Thanks
-- Len Turnbull
Possibly the turbo exhaust turbine oil seal weeping alittle- however you woould probably see blue smoke from the exhaust- unless you still have a cat fitted inwhich case the cat will be burning the oil- no blue smoke.
Practically the only way to check is to drop off the downpipe from the turbo before the cat and inspect for oily excessive carbon type residue in the pipe- but its easier said than done!
Tim..
Apart from the fact that you should not be towing anything over the kerbweight of your vehicle as you will put quite a strain on your transmission. I suspect that this has led to the high oil consumption you are experiencing. You could try thoroughly cleaning the PCV (Positive Crankcase Ventilation) system. Although there should not be a filter in this system due to turbo it can still get clogged up. This will force oil through the most unexpected orifices and could also be a cause of your oil consumption. If neither of these improves matters, you should consider a reconditioning of the engine as the bores are probably a bit oval with all the excess hard work your engine has been subjected to. Is your engine a B200 or B230 series? There is likely to be more wear with the B200 motors than the B230 ones, as the B200 ones are 2 Litres and the B230 ones are 2.3 Litres.
Cheers, Peter.
I disagree peter, both the B200 and 230 are the low friction units which do wear slightly quicker than the B19 and 23 that they replaced, but neither is weaker than the other whether in turbo or non turbo form.
However, yes the OP's PCV system could be clogged and would be the first thing to check...
Tim..
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