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oil in the air filter housing.....


EHess's Avatar
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05-11-05, 01:19 PM   #1  
EHess
oil in the air filter housing.....

I own a 1991, Mazda B2200, 5 speed, that is accumulating oil in the air filter housing. It looks as though it's travelling through a hose that comes off the valve cover. there is a filter, where the hose meets the air filter housing. I did a tune up, pugs and wires, air filter, distributor cap and rotor, cleaned up the air filter housing, and the little filter at the end of the hose. it was running fine, unitl I took it on a 100 mile round trip. After getting to my destination, i felt a problem while idling. By time I got back home, it would stall while idling. When I got home, I noticed more oil in the air filter housing. Half of the filter was soaked in oil. I'm guessing the rough idle may be a fouled plug? it runs fine going down the road, just idles real rough. My main question is, why is this oil getting all up in the air filter housing?

 
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05-11-05, 02:05 PM   #2  
Did you replace the PCV valve? If not, try that first. Don't try to clean it, it's only a few bucks for a new one. If it continues, you will probably need a compression check and may have failing piston rings.

 
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05-11-05, 02:35 PM   #3  
EHess
thanks goldstar. god I hope it's not the damn pistons as you say. the pcv valve, is that the little foam filter at the top of the hose from the valve cover?

 
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05-11-05, 09:11 PM   #4  
I'm not sure where they hid it on your car. It's usually a black plastic or silvery metal cylinder. If you follow the hose to the air cleaner back to the engine, you may find it as the connecting link between the hose and the valve cover or engine block.

 
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05-12-05, 06:53 AM   #5  
the pcv valve...

...won't be at the end of the hose with the filter. fresh filtered air is drawn thru that hose with the filter and flows toward the valve cover to replace the nasty fumes and combustion gasses that are in the crankcase. the pcv valve will be attached to a manifold vacuum source and be inserted into the crankcase...frequently the valve cover...it may screw in.

 
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05-12-05, 07:36 AM   #6  
EHess
thanks carguy. do you agree with goldstar in that the oil in the filter may be caused by bad pistons?

 
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05-12-05, 07:42 AM   #7  
bad pistons...

...or rings. the fact that you have an idle quality problem says that you may have a piston burning thru. the best way to be sure is to perform a cylinder leakage test...a compression test os ok...but doesn't tell the whole story. a leakage test will pinpoint exactly where the compression is going...basically tells you how well the cylinder is sealed.

 
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