Oilly Air Filter

39857 · Aug 9, 2004

Does someone know what it means when your air filter gets oil on it, it is happening allot latley.
PS when that baby hit 200k miles problems started popping up like carzy, just did the CPS today and started doing a rear tranny seal...fun fun fun.

Texas ZJ1 · Aug 9, 2004

Wow,

stumped me on this one. My air filter is always oily because of the filter element.

Hunter

39857 · Aug 9, 2004

Texas ZJ1 said:
Wow,

stumped me on this one. My air filter is always oily because of the filter element.

Hunter

Are you saying that the air filter in my 4.0 I6 is supposed to be soaked in oil, I have two vents on the top of my valve cover, one is in the back and the one near the front has a tube going to the air filter box so I assume oil can get over there, but it doesn't look like any air can get through it, because it drips oil, only the edges, the center of the square air filter is still dry.

miataeric · Aug 9, 2004

jeepholic said:
Does someone know what it means when your air filter gets oil on it, it is happening allot latley.
PS when that baby hit 200k miles problems started popping up like carzy, just did the CPS today and started doing a rear tranny seal...fun fun fun.

Sounds like blow-by to me.
Google says: http://www.off-road.com/jeep/cherokee/xjtech/engine/40ltr/blowby.htm

39857 · Aug 9, 2004

That's it exactly thanks so much!!!!!!

Texas ZJ1 · Aug 10, 2004

No, your's is supposed to be dry. I have the turbcity dual air intake. Mine is supposed to be dry hence me saying that you really stumped me on that one.

Hunter

LBX2G · Aug 10, 2004

I asked my high school mechinic teacher about this. He said it is cloged and to replace the ccv valves and not to worry about. and that is normal wear and tear. Nothing to pull ur hair out about.

40033 · Aug 10, 2004

I've had this problem as well on my '94 4.0 I6. It seems under acceleration the front CCV on the valve cover can "spit" oil from the crankcase out onto the air filter. To remedy this problem I have simply removed the hose that goes from the front valve cover CCV to the factory airbox. Placed a breather filter on the front valve cover CCV nozzle and blocked off the airbox nozzle.

No problems or oily air filter in months now

.

greasefingers · Aug 10, 2004

This issue should really be a "sticky" It has been written up several times in great detail. I will tell you what I know: the rear plastic line is connected to the intake manifold. The manafold pulls a slight vacuum on the valve cover and recycles the blow-by gases back into the combustion chambers. The front line is connected to the air filter. From this line, it purges the blow-by gases with fresh air. If the rear line is disconnected or block/clogged, then you do not have a purge in your valve cover anymore. If blocked then the valve cover becomes slightly pressurized, so the oily vapors are force in the reverse direction to the air filter and deposit on the top of the filter. Remove the rear line and clean it with brake fluid. If this CCV line is disconnected, then you may smell and see the vapors.

The two elbows at each end of the 4.0 liter engine are different. The one at the front is a normal elbow(Mopar pn# 53030497 $4.60) This allows a fresh air purge of the vapors inside the valve cover. The rear one is called the vent or CCV valve (Mopar pn# 53030495 $6.10). Gases flow out of this and into the Intake manifold. One end of the CCV vent, the part inside the valve cover, has a metered orifice in it about 1/8" OD. This meters the amount of blow-by gases introduced into the intake manifold. You will also need two rubber gromets for the valve cover (Mopar pn# 2946079 $ 4.35/ea)

slaterny · Oct 17, 2004

misleading thread

I love this jeepforum, but I have an issue with this particular thread. It sounded like what was described here is exactly what was happening to my zj. I clicked on the link that has a detailed description along with specific mopar part numbers for a fix. I went to the dealer and got the exact part, but it didn't fit! It turns out that the link with the part numbers was for xj's not zj's!

Looking at it after the fact, I see that now, but when you are trying to diagnose and fix a problem, I guess you assume that any information under the "Grand Cherokee" forum would be related to just that.

That's my .02

39857 · Oct 18, 2004

The link was directly to an XJtech page, even has a pic of an XJ, and while the problem is the same the part #'s may be different.
About the problem, once I cleaned my vents and made sure I had good vacum in the back vent the problem went away. The valve cover makes a vacum inside, and with out it you will get oil on the air filter.

Meerkat · Oct 18, 2004

greasefingers said:
This issue should really be a "sticky" It has been written up several times in great detail. I will tell you what I know: the rear plastic line in connected to the intake manifold. It pulls a vacuum on the valve cover and recycles the blow-by gases back into the combustion chambers. The front line is connected to the air filter. It purges the blow-by gases with fresh air. Your rear line is disconnected or block/clogged. So you do not have a vacuum in your valve cover; anymore. The valve cover is now pressurized, so the oily vapors enter the air filter and deposit on the top. Remove the rear line and clean it with petrol.

Ask, and ye shall receive....
FAQ entry

:thumbsup:

49670 · Apr 13, 2005

slaterny said:
I love this jeepforum, but I have an issue with this particular thread. It sounded like what was described here is exactly what was happening to my zj. I clicked on the link that has a detailed description along with specific mopar part numbers for a fix. I went to the dealer and got the exact part, but it didn't fit! It turns out that the link with the part numbers was for xj's not zj's!

Looking at it after the fact, I see that now, but when you are trying to diagnose and fix a problem, I guess you assume that any information under the "Grand Cherokee" forum would be related to just that.

That's my .02

Hi...

On the bottom of that detailed description of how to deal with the problem it said that it was for Cherokee/Comanche Jeeps only... But I guess it is "misleading" in a way if you don't read the whole article.

Have a good one guys...

53894 · May 24, 2005

Exact Problem!

FIRST OFF.
In a CCV (Constant Crankcase Ventlation) there is no one way valve like in a PCV (Positive crankcase ventlation) on a V8. The 2 plastic fittings on top of the valve covers are elbows only. What limits the airflow is the oriface size (brass fitting). The purpose isn't to pull a vacuum in the crankcase but to maintain a slight low pressure so blowby gasses will not cause performance problems with the engine. It all works good but usually gets 0% maintenance, so by the time the adverage Jeeper gets it the system isn't working correctly.

When I bought my '94 ZJ 4.0L, it had an oil smell while driving.
When I check under the hood I noticed a oily vapor coming out around the CCV gromets on the valve cover. Closer investigation showed that all parts of the CCV system was pretty much shot. The brass oriface that screws into the intake was totally clogged so it couldn't have worked anyway.
Went to the Jeep dealer parts counter and discussed the problem. It turns out it is very common on Jeeps with the 4.0L and they knew all the part numbers by heart when I told them the year. The breather tube was out of stock but they pulled one or a XJ and said to turn it around backwards and it would work. The bends in the plastic tube are in different places for a XJ. Everything was less than $50 and I installed the parts and had a working CCV system.

54374 · Jul 8, 2005

i worship this thread... i thought i was screwed. my local mechanic told me i was going to need an engine rebuild.

Brian's 97 ZJ · Jul 8, 2005

GettinStuck,

I wouldn't use that mechanic.

- Brian

53755 · Jul 9, 2005

Anyone know if you can just pull the two elbows off? I tried, and it seems like I'm going to break something they are so tight.

Scottso699 · Jul 9, 2005

you can pull of the elbows - the front one is the same size diameter as the outside the rear one has a pinhole sized hole at the connection to the valve cover - when this pin hole gets clogged the vacum from your air filter starts to pull oil from the valve cover rather than the rear one evening the pressure between the valve cover and intake manifold - I had the same problem with my 95 ZJ 4.0L - just popped the rear elbow off - cleaned it out and replaced the rubber grommet and plastic hose connection (it desintigrated on me) and it solved the problem.

Brian's 97 ZJ · Jul 9, 2005

The elbows may also break when you try to take them out. They press pretty tightly into the grommets and they will become brittle over time. I was unable to take mine out without breaking them.

Here's the Catch 22 that I ran into: I wanted to remove the valve cover before I tried to remove the elbows, so that if they broke, plastic wouldn't get into the valve train. Except the proximity of the rear elbow to the cowl didn't allow me to lift the valve cover over the rockers far enough to get the valve cover off.

HTH :thumbsup:

- Brian

greasefingers · Jul 9, 2005

Dai_Ryu said:
Here's the Catch 22 that I ran into: I wanted to remove the valve cover before I tried to remove the elbows, so that if they broke, plastic wouldn't get into the valve train. Except the proximity of the rear elbow to the cowl didn't allow me to lift the valve cover over the rockers far enough to get the valve cover off.

HTH :thumbsup:

- Brian

Now that's funny :rofl: Stop using your brain and get a hammer man! You smash that freakin thing then remove the valve cover and spend the rest of the afternoon cleaning all of the bits out!!!

66654 · Dec 31, 2005

So does anyone have the correct part #'s for a ZJ or is this thread dead?

Woody · Dec 31, 2005

Go to a dealer, they can look it up. This thread has now been reincarnated twice.:brickwall

dos0711 · May 11, 2006

Because it is an awesome thread!

sastanley · Nov 20, 2006

Yup..thanks for this thread. my rear tube broke off at the valve cover this weekend when I attempted to clean it.

For a 1993 ZJ, as of Nov 2006, the front tube is $12 and the rear tube is $16 from my local dealer. I am picking them up today.

greasefingers · Nov 20, 2006

That’s because every 4L engine on a ZJ, will dump oil on top of the air filter at some point in time. Same thing with the oil pressure sender. It’s garbage and will leak. Both the CCV valve and the oil pressure transducer should be on the 100,000 mile maintenance schedule. (as a replacement part)

sastanley · Nov 20, 2006

greasefingers said:
That's because every 4L engine on a ZJ, will dump oil on top of the air filter at some point in time. Same thing with the oil pressure sender. It's garbage and will leak. Both the CCV valve and the oil pressure transducer should be on the 100,000 mile maintenance schedule. (as a replacement part)

My ZJ has 208K on it...I bought it with 191K on it. The previous owner was not what I'd call a 'regular maintenance' type of guy. I am finding all kinds of goodies

:wave:
Also on the list:
rear main seal
rear wheel bearings
getting the play out of the steering

Oilly Air Filter

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