oil in the intake.. some info needed | Ford Explorer Forums - Serious Explorations

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oil in the intake.. some info needed


Jack from JackOffRoad
August 26, 2004
Reaction score
City, State
West Virginia
Year, Model & Trim Level
1993 2dr
I was looking over the top of the engine today and noticed some spots on the dr side valve cover where oil had dripped. I take a look at the vacuum tree and notice that the rubber connectors on the 2 small plastic hoses were swollen, i take them off and there is noticeable wetness from oil in the vacuum tree. I know from searching that one of the plastic lines runs to the filter box and the other to the FPR. I plan on capping the one going to the filter box seeing as the box isnt even in the truck anymore.

Obviously oil getting into the FPR isnt a good thing so I need to try and find whats causing the oil in the intake. It does seem like oil and not tranny fluid so that rules out the trans modulator valve. The pcv valve is new and i did not notice any wetness in the hose from the valve to the intake. The intake gaskets are new, as well as the valve cover gaskets. I know that some oil is normal but this seems a bit excessive. Any help or guidance you guys can offer would be greatly appreciated.

well i just went out and pulled the hose off of the FPR and there was oil there also. so until i can pinpoint the exact problem i replaced the line from the FPR to the vacuum tree with a piece of rubber vacuum hose and placed it on a port facing up on the tree.

still would like to find out where the oil is coming from.. seems to be more than a little spray from the pcv system. is there any other way oil can get in the intake? if the only way is the pcv system than I was thinking about installing an inline filter or seperator like i have seen some on this site do.

I hope I'm wrong, but check your air filter box and the throttle body area. If there's engine oil there too, you might have a plugged PCV valve. However, my experience was that there was too much blowby from the piston rings being worn out. It was bad enough to eventually blow out the rear main seal and the valve cover gaskets. Mine was an extreme case. Hopefully yours is much easier to fix.

I do have a small leak from the rear main, just had the valve cover gaskets replaced, TB looks clean, engine runs great.. its due for a tune up though.

After some more looking I realized that my tranny fluid isnt pink anymore.. its rusty brownish pink, just like the 'oil' that I found in the vacuum lines. So I'm leaning towards it actually being the trans modulator valve.

What are some symptons of the trans mod valve failing?