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Blow back

supsa

NAXJA Forum User
Location
seattle
The blow back to air filter is running oil all over the place. Vacuum line are clear. Anybody know ?
 
Thanks I'll check the crank case. Also don't know which one of the Timbertamers saved me at Evens last month. Just needed my tire back on the beed. They came for a night run. I thought I was on my way to Burnet store. Thanks Timbertamers
 
hope this helps



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Jim Grant's Tech Tips

[FONT=Arial, Helvetica, sans-serif]'90 Jeep Cherokee, Oil Loss Through Valve Cover[/FONT]
[FONT=Arial, Helvetica, sans-serif]Q: I've been losing oil (not burning) in my ‘90 Jeep Cherokee with a 4.0 liter engine. The very top of the valve cover always has a lot of oil on it from the rubber grommet type hose connection to the end of the cover. I ran the engine while looking at the cover and noticed some oil bubbling around this rubber grommet/plug. I'm assuming that this is where the PCV valve is located. This rubber connection leads back through a system of small diameter plastic pipes to the air cleaner. I do see oil or evidence of oil around this system. I'm suspecting that the oil is being blown up and out of this rubber plug type connection in the top of the valve cover and then it just runs down the top of the valve cover and eventually down to the ground. It is my understanding that there is a known historical problem with this engine regarding the valve cover gaskets. But I don't see that the oil is going out of the gasket, as it looks like it's blowing past this rubber plug/connection. Does this sound familiar or common? What is the solution? Obviously I could replace this ventilation system (and PCV valve if that's what it is) but I don't really want to spend the money for plug and chug mechanics. Nor do I want to be ripped off by the Chrysler dealer. Can you give me some answers, suggestions or referrals?[/FONT]
[FONT=Arial, Helvetica, sans-serif]A:[/FONT] [FONT=Arial, Helvetica, sans-serif]Plug and chug mechanics? I like that one. You’re problem is a common problem and it is easily fixed. Your Jeep doesn’t use a PCV valve persay. There are 2 hoses from the valve cover of your engine. The larger of the 2 travels to the air cleaner box. The smaller hose/tube which is mainly plastic travels to a fitting on the intake manifold. The most common problem with this system is the small plastic tube and/or the fitting on the intake manifold becoming restricted and plugged with deposits. The fix? replace the plastic tube and be sure to clean the fitting on the intake manifold. Don’t waste time trying to clean the plastic tube it just doesn’t happen. With a little plugging and chugging your Jeep won’t be blowing oil bubbles any more.[/FONT]
 
Also may not hurt to take your valve cover off and completely clean it. I have this exact same problem. Read some posts on here and in the jeepforum FAQ and recommend changing the CCV grommet/hose from the valve cover to intake manifold, as well as the breather hose from the front of the valve cover over to the airbox. The breather hose comes as two seperate assemblies (from a jeep dealer that is) and they eath run about $45. CCV grommet and hose are only $16. Try this first. The oil, time, heat and gasses all cause this grommet to break down, and I'm pretty sure it's supposed to be not only clean and clear, but also a certain size (3.2mm i believe.) Taking the valve cover off and really cleaning it may not be a bad idea either. Getting the gunk out of there will eliminate a variable in the question. Good luck, and keep us posted if you get it your problem to go away. I can't wait to fix my blow-by problem, as I am running without my filter right now just because I would be practically soaking it in oil after after drive.

-Chris
 
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I'll open it up and clean it out. It is geto rigged from a wrecking yard. THe first thing I did was replace the valve cover gasket and clean out all the vacuum lines. It worked for a while. For now I'm running with out the filter. Any of you guys fromWA going to Evens this weekend
 
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