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blowby and high crankcase pressure - also a possible heater fan repair 850

I have a 95 850 normally aspirated with 112000 miles - I am experiencing high oil usage (around 1 qt per 1000 or fewer miles). There is definite positive pressure at idle when I remove the oil filler cap (especially with hot engine). The dipstick tube gets oil on it too and there is seepage from the camshaft position sensor. I change the oil every 5000 miles and it seems quite dirty for that mileage. I have been cleaning the flame trap about once a year but I have never seen it very dirty or blocked. There is sometimes a little oil settled inside the throttle body and inlet air hose - enough to pick up easily with a paper towel, no more.

I pulled off the hose that draws air from the top of the cylinder head and runs down to the oil separator box. At idle I feel no vacuum on this hose. I can blow air through the hose (with oil filler, dipstick and hose port on head closed off) and it comes out the flame trap but this is not easy - there's some resistance.

I think either there is way too much blowby in this engine or the oil separator and hoses are badly clogged. Has anyone examined their oil separator and found problems? I don't want to get into mechanical issues with the engine unless I can eliminate simpler causes in an otherwise well performing car. I've never detected smoke in the exhaust. I didn't check compression or manifold vacuum yet.

Here's the heater fan issue - some people seem to have these fans quit or not work on certain speeds. I have also had problems. Instead of replacing the fan, resistor, etc., I cleaned up all the wiring connections and also the commutator on the fan motor with very fine 600 grit aluminum oxide paper. Everything supplying power to the motor was very dirty. The fan works great - at least so far.

Thanks to everyone...
ksg






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New blowby and high crankcase pressure - also a possible heater fan repair [850]
posted by  someone claiming to be ksg  on Mon Jun 14 12:02 CST 2004 >


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