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post #1 of (permalink) Old 10-12-2002, 01:29 AM Thread Starter
 
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Oil in the air cleaner?

I've got an 88 grand wagoneer. Oil is sucking up through the vent tube that runs from the oil fill cap to the air cleaner housing and is leaving oil sitting around the air filter. Also the cap on the oil fill tube allows the oil thats being sucked through the vent tube to fall out onto the intake manifold. Anyone know how i can fix this? Also, would it hurt to just get rid of that vent tube and get a better cap for the fill tube? I'm not running most of the emissions equipment on the motor either if that can effect it. Thanks.
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post #2 of (permalink) Old 10-12-2002, 10:56 AM
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Re: Oil in the air cleaner?

There are caps that will fit the tube and they have breather holes at the bottom.
I think you should solve the problem though, because I don't think your carb would be trying to breath through the manifold if it had free air flow through the cleaner.
It sounds like you retained the original air cleaner and it may be that the vacuum operated diaphram/s may not be operating correctly to allow proper air flow. I believe they are controlled by the thermo switch which routes the vacuum to open the diaphrams which adjust the vented air flow.
For all that you can certainly switch to a K/N filter, but you'll loose your exhaust manifold heat (which is nice in the winter if it gets very cold where you live) and be more likely to consume water that may fly around your engine compartment on fordings. Also, you can't fit a very tall K/N under the hood without a body lift, I believe my filter was about 2" tall.
Also, be sure that your pcv is functional and clean.
post #3 of (permalink) Old 10-12-2002, 02:10 PM Thread Starter
 
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Re: Oil in the air cleaner?

I pulled the vacuum diaphragm off the air cleaner housing and have the door for the exhaust heat held open with a screw that i put through the rivet hole that held the vacuum diaphragm on. So air flow "should" not be a problem.

My first thought was the PCV, but i just replaced the pcv and all the vacuum lines. I'll check it out though. Thanks[img]images/graemlins/crazy.gif[/img]
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post #4 of (permalink) Old 10-13-2002, 10:37 AM
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Re: Oil in the air cleaner?

If it is not a matter of restriction of air flow through the air filter assembly then the carb is not "sucking" oil up through the breather tube. The breather tube is designed to vent the manifold up to the carb not to transfer oil.
Oil is being pushed up with vented manifold pressure possibly because of increased crankcase pressure resulting from piston ring blow by (have you done a compression check lately?) or possibly the manifold has been removed and replaced without a lifter valley pan gasket being installed. If the valley pan gasket was not installed (some mechanics leave it out believing it causes coolant leaks and simply RTV the manifold to the heads and lifter valley using only the two end seals) then those gases venting up from the lifter valley through the manifold will carry oil with it. The valley pan gasket would stop the oil from rising through the manifold while allowing gases to rise and vent.
In either event if you merely cap the breather tube it will continue to vent oil if you don't fix the problem, only it will purge oil onto the front of your engine instead of the just into the air cleaner.
If there is another reason for oil to purge with the gases I have never heard of it, and if anyone else has a suggestion I'd appreciate learning more myself.
I've never heard of a manifold being so gunked up that the PCV passage was clogged, but I suppose you shouldn't rule that out.
Let me know if you get it solved.
post #5 of (permalink) Old 10-24-2002, 12:12 PM
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Re: Oil in the air cleaner?

I have a 78 waggy with a 360ci which is doing the same thing. Someone before me has removed the pcv system and the tube for the exaust emisions. since there is no pcv valve could that be the reason for the oil blowing into the air cleaner?
post #6 of (permalink) Old 11-07-2002, 10:31 AM Thread Starter
 
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Re: Oil in the air cleaner?

I drove my wagoneer 275 miles one way trip twice this week and had no problems with oil getting in the air cleaner housing like it had been[img]images/graemlins/smirk.gif[/img]? I haven't replaced anything since i asked about it other than the fuel pump.
I figured I'd also mention that it got 17.34mpg on the down hill part of the trip and 17.19mpg on the up hill [img]images/graemlins/smile.gif[/img] Thats the best this jeep has ever gotten and with 201,000 miles on the motor too. Maybe it was all the tune up work i've done to it or the new fuel pump, or maybe I finally learned how to control my right foot [img]images/graemlins/wink.gif[/img]
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post #7 of (permalink) Old 11-07-2002, 10:37 AM
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Re: Oil in the air cleaner?

It sure is nice when jeeps fix themselfs ! Congrads. Also congrads on a 360 with 200+K. That gives me hope that mine will run strong for quite some time. 166K on mine, and I only drive about 8 miles a day to and from work. 4miles each way. But it is winter now and bring on the ski trips.
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post #8 of (permalink) Old 12-07-2002, 03:11 PM
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Re: Oil in the air cleaner?

This is more common then you might think, once you get around some other fsj's. The most common problem is the excessive blow by from bad rings or valve guides. But, if your pcv system is not functioning properly it will blow oil out the fill tube and into what ever you have it hooked to. If you have it "open" like a breather cap it will spray all ove your engine, thanks to the fan. It is possible (i have seen ot only once) that the "slotted" vent like things on the underside manifold baffle will fill up with cooked oil, and clog. A visual inspection would require the removal of the intake, but it should be easy enough to check the PCV with vacuum and see that it is clear and that the valve is functioning properly. I would think your problem may have been a stuck PCV valve if it was only temporary. 17 MPG???? I'm green with envy. [img]images/graemlins/shocked.gif[/img]
post #9 of (permalink) Old 12-07-2002, 08:27 PM Thread Starter
 
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Re: Oil in the air cleaner?

That 17mpg was a freak thing. It usually gets 15-15.5mpg on a long trips and 11-13mpg on short trips. Its been running better lately because of a long overdue tuneup that I gave it in the summer. I would think I calculated it wrong but not both ways. The last time I made the trip it got 15.5 down hill, 15 up hill, and no problems with oil in the air cleaner. [img]images/graemlins/smirk.gif[/img] It started spark knocking under load though so that will be my next thing to fix. [img]images/graemlins/tongue.gif[/img]
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