Was having a cage installed on the heap, and figured while it was in the shop I'd replace the glasspack with something quieter for the long road-trips.

When they took the glasspack off, they called me and said that I have oil in my old muffler!

When I drive it, I have NO smoke of any color, from the exhaust or anywhere else. I do SMELL oil burning, but there is no smoke, so I just assumed it was a drip onto the exhaust somewhere. Shop's thinking was that the oil in the muffler is blowby past the piston rings, but I have NOTHING indicating loose rings or cylinders; no knocking/slapping, no low oil pressure, and I am not burning through oil, etc. I even asked if it was OIL they found or just water/soot. They were sure it was oil.

It's an XJ, 2001, with 190K on it, original 4.0IL V6. Has plenty of power and acceleration, even rolling 35's on 4.56.

Anyone seen/heard of this before? Any solid thoughts on what it ACTUALLY is? I've seen/heard rings, valve seals, and valve stem guides, but ALL seem to be indicated by SMOKE, which I don't have.

Assuming it is the piston rings, if I keep oil in it, can I just keep driving it, or am I likely to throw a rod?

 

How much oil are you losing between oil changes?

 

I just bought it in July and haven't run it enough to warrant an oil change. According to the dipstick, everything is just fine.

The "oil" was wet when they pulled it off the other day (they said it dripped out onto the shop floor), but it was dry by the time I got there.

The shop is reputable and reliable, I'm just trying to make sense of it.

How do you get that much oil into a muffler without smoke?

 

If your dipstick is fine, then you're not losing enough oil to worry too much.

Most likely, you have a tiny leak in the bottom/back of your engine and it's just slowly dripping to the muffler.

You can fix it (recommended), but if you're not willing to put in the time and money, it's not going to hurt anything either if your dipstick shows that you're full. Except, maybe, your health from breathing in the fumes.

 

My only experience with blowby is in rotary powered mazdas, they consume oil at an alarming rate. A rotary running "perfect" will make a quart disappear in 2500-3000 miles.

I would assume if blowby is your issue you'd see a serious difference on a dipstick.

 

Oil doesn't dry up on floors.

 

That was my first clue!

 

hahaha must been snake oil instead.

 

My feelings exactly, maybe fuel mixed with soot in muffler?

 

Pulled the plugs today and did a compression test. most were 145-150. #1 was 135 twice. Put some oil in the cylinder and nothing changed. (Remember, this is an engine with 190K on it!) Replaced the plugs with fresh ones. Also checked the oil again. Turns out I was down about 3 quarts. Filled that up. She started right up, burned off the oil I put in the cylinder, and now she purrs like a kitten. I definitely have an oil leak, but it isn't blowing by the rings!

 

Here's how to find the oil leak.




I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.

Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.

Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?

A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.

First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

Revised 02-26-2013

 

My guess was just water with a little soot

The "oil" wouldn't dry up on the floor as said above