Burning oil

mgroeger

mgroeger

TJ Enthusiast
Joined
Aug 24, 2018
Messages
807
Location
Hurricane, UT
2004 LJ, 4.0, auto, 120k miles
I do have the rear main oil seal leak and I get the little dime shaped oil stain where I park. I can also see I'm a little damp on the driver's side of the engine from a valve cover weep and possible oil pan gasket weep. NONE of this is causing any substantial leaking or oil loss.
After 1k miles I was shocked to be 1 qt low since I had never seen that before. Then I noticed that the filler cap said 10w-30 oil and I had just put in 5w-30. It gets very hot here in the summer, on top of that I off road it and the motor has 120k on it. Is it possible that the engine consumed that qt. because it was too thin of an oil? I have not seen this issue before when it was cooler out.
I do plan on bumping to 10w-40 for the summer and 10w-30 for winter. Also, there is no smoke at start up or at any time when driving. The exhaust does have a slightly richer smell on start up than my wife's 2018 Wrangler but that is to be expected. When I allow the Jeep to warm up in the garage I do get black tiny dot splatter on the floor from where the exhaust hits.
 
Well the tiny black spots could either be just carbon deposits "rinsing" out from the condensation that build up... Or it could be a little oil that's getting past the rings, which would cause oil consumption
 
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Ante_Up said:
Well the tiny black spots could either be just carbon deposits "rinsing" out from the condensation that build up... Or it could be a little oil that's getting past the rings, which would cause oil consumption
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They absolutely look like carbon deposits, I only mention them because I am trying to cover all bases. They have been around from day one when I noticed no movement of oil on the dipstick.
 
Today's catalytic converters can mask oil consumption, no blue smoke when running. If your consumption persists, you may want to consider disconnecting from the manifold (2 bolts) for a quick run just to make sure it's not internal engine wear, rings, valve seals or guides.
 
Burning some oil doesn't really call for concern, my opinion from experience.
Some of the better vehicles I've owned over years required topping off between oil changes.

You can go to a high mileage oil that has additives to reduce the amount of leaking, works for me.
 
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The 5-30 probably had nothing to do with the oil loss. When the engine warms up it is acting like a 30wt just like a 10-30 oil will. The 5wt was/is mostly for mpg purposes believe it or not. Most vehicles will spit a bit of black moisture out the tailpipe on startup in the right conditions. It's mostly condensation from the cooling exhaust the night before. Is this the first you've noticed oil loss? 1 qt in 1k miles would be obvious when changing the oil/filter. Could you have just been a qt low last oil change?
 
Goatman said:
The 5-30 probably had nothing to do with the oil loss. When the engine warms up it is acting like a 30wt just like a 10-30 oil will. The 5wt was/is mostly for mpg purposes believe it or not. Most vehicles will spit a bit of black moisture out the tailpipe on startup in the right conditions. It's mostly condensation from the cooling exhaust the night before. Is this the first you've noticed oil loss? 1 qt in 1k miles would be obvious when changing the oil/filter. Could you have just been a qt low last oil change?
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This is the first I have noticed oil loss. The 4.0 takes 6qts and Valvoline has a 6qt box of oil that I use. I'll be baby sitting now to see what happens. Next weekend I will be using 10w-40, fresh filter and making sire it is on the money.
 
Clean the engine and put the correct 10-30 oil in it. Look for leaks and repair the leaks. A tiny bit of weepage at some of the seals and gaskets is no cause for concern, and also no reason not to repair if you are so inclined. I insist on zero oil leaks because I am anal about lubricant leakage. That sentence could be misconstrued. Myself, I would fix the valve cover gasket and rear main. I had a Chevy truck with an 8.1 in it. Used oil a quart every 1000 miles from day one. Chevy tried to convince me that was normal. It was normal, for that specific engine I guess. Using a quart between oil changes in a higher mileage engine is not a huge deal. Likely it is in the top end. Do a compression test wet and dry and go from there, or add a quart every 1K. If it runs well and uses a bit of oil, not a big deal.
 
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Goatman said:
How many miles till next weekend? Is the oil level continuing to drop, or is it stabilized?
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So, as noted it's been about 500 miles since I last checked and I'm down almost a qt again!!! WTH. No smoke, no strong odor, no leaks, I'm at a loss. I need to get different oil in it and I am def going with 10w-40 instead of 10w-30. 120k miles on the engine and temps in the 90s w/ high humidity, the old schooler in me says to go with that.

Here's a question though, I have a 1" brown dog motor mount lift. Does that change the angle of the engine enough to affect the reading on the dipstick?
 
You're saying this only started after changing the oil. Check the oil filter; is it screwed on firmly? It's possible the gasket from the old filter stuck to the engine, so the seal is compromised? If you weren't burning oil previously and you merely went to 5w-30, that doesn't make any sense.
 
bromel said:
You're saying this only started after changing the oil. Check the oil filter; is it screwed on firmly? It's possible the gasket from the old filter stuck to the engine, so the seal is compromised? If you weren't burning oil previously and you merely went to 5w-30, that doesn't make any sense.
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Agree... it doesn't make sense. My garage floor is clean, at this point it is going to be a matter of a fresh oil change and baby sitting. Frustrating to say the least.
 
I live in a brutally hot region. I use 10-30 with great success. My advice you are welcome to ignore is to use dino oil and stick to what belongs there. 10-40 shouldn't hurt, but I doubt it will plug leaks or stop burning. Before you change oil, do a wet and dry compression test. Maybe a cylinder leak down will point you in the right direction should you get questionable results. A missing quart of oil would make a significant mess.
 
Flivver250 said:
I live in a brutally hot region. I use 10-30 with great success. My advice you are welcome to ignore is to use dino oil and stick to what belongs there. 10-40 shouldn't hurt, but I doubt it will plug leaks or stop burning. Before you change oil, do a wet and dry compression test. Maybe a cylinder leak down will point you in the right direction should you get questionable results. A missing quart of oil would make a significant mess.
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Thanks. All I use is dino oil since that is what has been run in this since day one. When you say dry and wet I assume you are saying dry = after engine has been sitting and is cooled off and wet = engine at operating temp?
 
You would pull all of your spark plugs and run a compression test on each cylinder, annotating the results on paper. If you have any cylinders with low compression, squirt about a teaspoon of oil in that cylinder and retest the compression. If it is your rings that are worn, you should get a good jump in compression on the wet compression retest. If there is little to no change, you may have bad valves. Check Youtube for the process, you may find it better explained. 120K is not a lot of miles on a 4.0, but parts can go bad. I had a tight engine, no leaks and ran well, but a couple lifters chattered occasionally. I found a ridiculously low mileage engine for $500 that had a very gentle life. I ended up swapping out the engine, tranny and transfer. I couldn't resist. My old engine only had about 90K on the clock, but it was not pampered by the previous owners. The quest for mechanical perfection is part of the fun of the hobby in my opinion.
 
I use 15w-40 in the summer. It is recommended for use in the engine in some areas where it is more common. I don't think it's going to do anything but you could go there without thinking twice. 10w-40 seems like not worth the effort to me. I have a large RMS leak and don't loose anything significant over 3K. You might pull the intake breather hoses that go to the valve cover and see if anything strange is going on. Sometimes the plastic piece in can get damaged and you can suck oil into the intake. That's the only easy fix I can think of.
 
Any chance to pull an O2 sensor PRE catalytic and see what the inside of the exhaust looks like? A quart in 500 miles is extreme oil consumption. There should be a ton of carbon in there. If it is clean then???? Do you have any elves or neighbors that could be f-ing with you? To go from 0 oil usage to 1 qt in 500 mi is only explained by elves or a broken valve guide or oil control ring.
 
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