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Another oil smell question.

Airsmitty

NAXJA Forum User
Location
Newhall, CA
Here we go!hasta
1991 Cherokee 4.0 Auto 4x4

I'll do this in a Chronological Timeline style!

1. Made a custom air intake out of PVC pipe and a cone filter. Drove for 2 weeks, no problems. Valve breather instead of hose for the CCV.

2.Went to the sand dunes. After a couple days the jeep was low on oil and started ticking. Filled it back up with oil, ticking gone, and the smell starts.

3. Drove home, oil smell and smoke on freeway hills. Drives fine around town.

4. Noticed EVERY valve cover bolt was loose. Tightened. Added oil, forgot to put the oil filler cap back on :doh:. Tons of smoke and the oil smell on my way to a wheelin trip in the mountains. Replaced cap and added oil.

5. Wheeled for hours and hours in the mountains, no oil smell. On the way back, it came back. Little or no smoke.

6. Routed the front CCV into my air intake. Still the smell. Replaced the rear CCV valve and tube(it was clogged!). Smell persists. Put stock intake back on with all the hoses, still smells going up hills.

My next steps are to clean the engine and replace the valve cover gasket, but it's strange to me that it only smells while I'm going up hills on the freeway. If it's truly just burnoff, wouldn't it smell no matter what? Am i missing something?
 
Last edited:
Here we go!hasta
1991 Cherokee 4.0 Auto 4x4


1. Made a custom air intake out of PVC pipe and a cone filter. Drove for 2 weeks, no problems. Valve breather instead of hose for the CCV.

2...Filled it back up with oil....

3. Drove home, oil smell and smoke on freeway hills. Drives fine around town.

4. Noticed EVERY valve cover bolt was loose. Tightened. Added oil, Replaced cap and added oil.

5. Wheeled for hours and hours in the mountains, no oil smell. On the way back, it came back. Little or no smoke.

6. Routed the front CCV into my air intake. Still the smell. Replaced the rear CCV valve and tube(it was clogged!). Smell persists. Put stock intake back on with all the hoses, still smells going up hills.

My next steps are to clean the engine and replace the valve cover gasket, but it's strange to me that it only smells while I'm going up hills on the freeway. If it's truly just burnoff, wouldn't it smell no matter what? Am i missing something?

Sounds like you are losing oil. The oil seems to be going away when you're under load (e.g. freeway, hills) either because the engine is under load and any leak is leaking more or because there is more air flowing thru the Jeep and you're better able to smell it.

Anyhoo, I think you answered your own question. Clean the engine, stop the leak.
 
So I've replaced the valve cover gasket and cleaned the engine off. It's no longer leaking from what I've seen. The main seal is still leaking, but it's been leaking for years and years and this smell has only been around for a few weeks. I'll replace it soon, but I'm afraid it's not the source of the problem. The smell started after I topped it off with oil and while I was going up a long hill at the sand dunes. I was revving the motor pretty hard out there to get up some of the steep hills.

Anyone have any other thoughts?
 
Well! I feel dumb. Found a hole the size of my fist in the top of my muffler. It was heating up the underside of the cab and making it stink!
 
Well! I feel dumb. Found a hole the size of my fist in the top of my muffler. It was heating up the underside of the cab and making it stink!


Doh! Time to screw one of those air-bake cookie sheets between the muffler and the floor pan. And of course replace the muffler.
 
Doh! Time to screw one of those air-bake cookie sheets between the muffler and the floor pan. And of course replace the muffler.

Haha good thinking! I went around town looking for a glasspack but everyone wanted $40+ for what they had in stock. Found a 30" straight pipe turn down that'll replace my muffler until I order something from summit next week.
 
$40 just for the muffler? Last muffler I had was $29 plus $20 to install. It was a hole in the wall place and the guy was perfectly honest and told me the $69 lifetime warranty muffler was the exact same part. The only difference was the warranty.
 
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