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-   -   Keeps losing oil, but no leaks...where's the oil gone..? (http://www.jeepgarage.org/f203/keeps-losing-oil-but-no-leaks-wheres-the-oil-gone-62951.html)

CAJeep 07-17-2013 12:39 PM

Keeps losing oil, but no leaks...where's the oil gone..?
 
I have a '02 GC Overland (149K miles) and seems to run OK, but for some reason, keeps going through oil like it's gas...

I noticed it was below the ADD marker on the dipstick about a month ago, so I added 2 quarts, checked it about 2 weeks later, and the level was back down to that same spot, below the ADD marker. So I added another quart, was above the ADD line, then a few days later, back below. I've done this a few times over the past three weeks and same result.

I see NO external leaks whatsoever -- nothing on the ground, nothing coming out around the seals around the engine, no signs of it spraying back along the transmission, etc. Basically can't find any external leaks.

So I'm thinking it must be an internal leak, right? But I have no smoke coming out of my exhaust and the car seems to run fine. One thing I noticed is that it seems to heat up to normal temperature more quickly than previously, but it doesn't go beyond the normal temp level, and this quick heat-up might be because it's summer and a bit warmer out lately...who knows.

Any ideas out there on where all this oil could be going...? Could it getting into the cylinders and burning up in the engine, but not showing smoke out the exhaust...? Any way to verify this?

Thanks for your advice.

BobTinKY 07-17-2013 01:56 PM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
I'm probably the least mechanical person on this site... but if it was my vehicle i would get an oil sample and a coolant sample and have them analyzed. I know the oil can be analyzed by sending it to Blackstone.

CAJeep 07-17-2013 02:21 PM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
Good thought on the coolant check. I forgot to mention, I also thought it might be leaking into the coolant, but the color is bright green, no brown-ish tint whatsoever, so I ruled out a leak into the coolant system. But maybe that was incorrect...?

AZhiCntry 07-17-2013 04:13 PM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
Quote:

Originally Posted by CAJeep (Post 859904)
Any ideas out there on where all this oil could be going...? Could it getting into the cylinders and burning up in the engine, but not showing smoke out the exhaust...? Any way to verify this?

Thanks for your advice.

If it's not leaking out it's going out the tail pipe. Check the EGR system. Have a leak down/compression test done on the engine. Even though you say it doesn't smoke it can be burning oil. A good mechanic can tell what's going on from the way the engine responds to a leak down test.
Have you had some one follow you closely while accelerating quickly and letting off the throttle abruptly. Smoking when accelerating indicates bad rings and smoking upon quick deceleration indicates leaking valve guide seals.

lstowell 07-17-2013 04:54 PM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
Quote:

Originally Posted by CAJeep (Post 859976)
Good thought on the coolant check. I forgot to mention, I also thought it might be leaking into the coolant, but the color is bright green, no brown-ish tint whatsoever, so I ruled out a leak into the coolant system. But maybe that was incorrect...?

If the oil gets into the coolant, you tend to get a rather nasty looking emulsion in a hurry as the water pump beats the oil into the water.

Valve seals, crankcase ventilation system, etc. could be letting it into the engine where it gets burned without obvious blue smoke out the exhaust.

Slow leaks don't seem the culprit, but just in case, there is dye you can get and put in the crankcase so a blacklight can see leaking areas that might not be obvious.

Noting the engine type might allow someone familiar with the "feature" to comment.

Frango100 07-17-2013 06:10 PM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
I would start changing the PCV valve. A stuck open valve will cause more then normal oil vapors to be sucked into the engine inlet.
I had quite some oil consumption on my 4.7 and also didn't see any smoke from the exhaust when accelerating, but finally saw it when decellerating and especially at night with an other car behind. Also when idling for prolonged time and then driving away, was showing a short but obvious puff of smoke.
The exhaust was getting black as well, while it normally was greyish. Pulling the plugs didn't reveil anything, as clean as could be.
I finally changed the valve stem seals and the problem was fixed. Just a USD 40 por the seal kit, but many hours of work to get them changed, especially the aft 4 cylinders.

Dirish1 07-20-2013 08:28 AM

Re: Keeps losing oil, but no leaks...where's the oil gone..?
 
My jeep has a possible rod or main bearing knocking due to a seemingly random oil consumption issue. One week it lost 2 quarts another 1 then all the sudden after passing someone on the E-Way I get a knocking under loads. Checked the oil and it was not even on the dip stick. Took 3-4 quarts to get it to SAFE. Never had a puddle or blowing smoke. I found the leak when pulling the tanny inspection cover. A rusted out oil pan so rusted thru that it was weeping oil but not when sitting in my parking spot. careful cleaning and observation of the area of the rusty old oil pan showed it was weeping and saturating the rust in the surrounding area and I asume that airflow when driving was wisping it away like an expensive air oiler lol.

My point is that even an odd occurrence can make odd things happen and it may take a lot of sitting under your Jeep gazing at it b4 you find whats causing your issue.

Be one with your Jeep and it will tell you what it needs.......


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