Date: Thu, 07 May 1998 10:26:27 -0500 From: colin hobbs <chobbsnopsamst.com> Subject: Re: Cure for smoking 900i (1985) ???
Robert, ok for starters is it a turbo? turbo's (when old) will feed in oil. I would check the installation of the valve guides. When old or improperlly instlled they will allow oil into the cylinder. (hey everyone makes mistakes) The mechanic replaced the compression rings. (good) but did he replace the Oil control rings? they are the 2 rings just below the compression rings. and if bad will allow massive amounts of oil into the combustion chamber. (remember all cars burn oil. you just want to minimize what oil it burns. normally it burns so little that you never notice because the rings and valves and head gasked are in working order) I suspect that somehow the oil control rings are bad or the compression rings were installed wrong. here is a good way to test the compression rings. check the compression. and then squirt oil in the cylinders if the compression improves dramatically then i would suggest that there is something wrong with the compression rings. ask the mechanic if he replaced the oil control rings. Robert Clark wrote: > I have a Saab 900 1985 (8-valve injection). The car spends long periods out > of use (sometimes several months) in a basement garage. > Recently, on starting after standing for about five months, it started > smoking badly from the exhaust - a cloud of bluish-white smoke when going > back on to the throttle after being on the overrun (eg after a downhill > stretch). The car has done 120,000 miles. Obviously it is burning oil. > A Saab-trained mechanic changed the piston rings and honed the bores. He > also fitted special seals to the valve stems. When the engine was put back > in the car it still smoked. > The mechanic then had the head pressure-tested. The test confirmed that it > is not cracked. But it still smokes. > Can anyone suggest a possible cause? > > Thanks > Robert Clark > England
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