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Oil in Air Filter


January 23, 2002
Reaction score
City, State
Central PA
Year, Model & Trim Level
96 Explorer XLT
I just purchased a 1996 XLT explorer, and after starting the general maintinence I notice a substatial amount of oil in the MAF, and in the filter. After closer inspection I found the source of the oil was from the hose that connects to the air intake to the oil filler spout. I have no idea why or how oil is getting from through that hose to the air intake?

The only thing i can think of is that that oil returns are plugged, and the oil is backing up, and thus overflowing into this hose.

Any help or suggestions are greatly apperciated.


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Just a shot but it may be you have alot of pressure in your crankcase to blow oil up into that tube. What does the oil press guage say? I would check your PCV valve. It should rattle when you shake it.

It could be something else though

it is a pcv related issue..... accumulation will happen over time....put that much sounds like a pcv problem.....

PCV issue

I thought of that too but when i check the PCV valve it seemed to be open (it rattled when i shook it) none the less i did replace that. Any other ideas?

Thanks guys


You may not wanna hear thins

How excess an amount of oil are we talkin' here? If its alot, its blowby from a tired engine. If thats the case, its time for a ring job. Run a compression test and see what you find out. You could keep the oil out of the intake by hooking a little breather valve to the end of the hose and capping off the inlet on the air intake, but if its blowby the only fix is a rebuild. Sorry, hope I'm wrong.



I hope your wrong too! :) I just purchased a compresion test gauge and will be doing that this weekend. I'll know for sure the health of the engine when i'm done.

Thanks again for the help !


check Compression and have a question

Okay, In my quest to stop moving oil to the air intake through the tube from the oil filler i've done the following:

1. Drained and refilled oil to the correct levels
2. Changed the PCV valve
3. Checked the compression
(New plugs and Wires while i was at it)

Now the question is what is the proper compression for the OHV engine? My engine tested at 150 ftlbs to 162 ftlbs for all 6. The pressure came up quick so i know that is a good sign but is the actuall compression good? All that i've read is that the lowest reading needs to be within 75% of the higest reading. Just wanted to know if anyone knew what the actuall compression should be.

Thanks in advance


Honestly I'd say that compression is pretty good... Hum... Well, I honestly, if the new PCV valve doesn't fix the problem and the compression is good, I am out of ideas :eek: . If it still dumps alot of excess oil into the intake, I'd put a breather on the end of the hose just to keep the intake clear.

Well, I am gonna drive it for the week and see how if any oil collects there now. But i am going to sleep better knowing the compression is good.

thanks for all the help


What kinda pvc is in there. I have seen many that rattled but were from Autozone and such and were bad. I put a Ford part in and have seen no problems. Something else to consider is how you drive the vehicle. Do you drive hard. If you do that will cause it too. My wife has a 97 Explorer and she drives like a tipical women slow and easy. I drive like a man fast and hard. I have a 91 Explorer. My filter is always oily. If you drive hard that will cause it too. One more thing you can do is unhook the hose that goes from the oil fill tube and start the truck up. Put your finger over the hole. If you feel alot of pressure you got a problem, then try the same thing at 2500 rpm. If you feel very little pressure you are ok on the engine rebuild.



I just wanted to thank everyone for the help. It seems after a week of aggressive driving that my oil issue has finally been solved! Yeap it was a bad pcv valve. I put the new one in a week ago and have driven it all week and not a drop of oil in the air intake.

Let this be a lesson to all, that even though they rattle doesn't mean they are still good. The one that was in it still rattled but after replacment the problem has been solved.

Thanks to all who responded. This is a great forum.