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My 88 4.0l MJ keeps blowing oil through the breather hoses coming out of the valve cover. I've cleaned all of the sludge from under the valve cover. There's no oil being burned and blown through the exhaust so I know the valves and piston rings are good. I just don't understand why it won't stop blowing out through the hoses. Any suggestions?
 

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I just had my valve cover off to replace the gasket so I did cut off the fluted tubes as suggested in above posting. The tubes already had a hole drilled in them. I don't have a lot of blow over to the air filter but enough to make it dirty. When I got my Comanche the blow over was terrible. When I removed the valve cover at that time it was full of sludge and was it restricting the flow of oil back down to the crankcase. My main problem is the gasket seem to compress over time and I have to keep tightening the hold down screws.
 

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Might try a rubberized cork gasket. I also changed to a '95 valve cover. It help a bunch. You would have to cut your CCV tubes. I also did the big CCV tube update. I was sucking a quart a week. Then it was good. I'd start with the valve cover gasket. Any air getting in that way seems to cause the problem.
 

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On my attemps with this, I found that the valve cover gasket sealing had an affect. Try a FelPro VS50522T. They are about $40. I order one to put on a late '95 valve cover on a '98 XJ. Also, the problem if the oil is going to your air filter, is that there is probably a air leak. The CCV system is not pulling enough air to counter act the suction from the air filter, and the extra air from the leak. So oil goes to the air filter. I did put a '91-95' '90 degree Twist' CCV valve cover on my '88. It helped a lot. I also adapted the big hose CCV hoses from a late model XJ '00-'01.
 
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