Maybe ya'll can better help me understand my situation. I have a '91 XJ with 205k+ miles on it. The engine runs strong, doesn't run rough or misfire, just great. However, Im confused by my oil consumption.

Now, Im not an idiot. Oil consumption is the result of worn rings, walls, valve seals, and Lord knows what else. I run Mobile 1 High Mileage 10w30 religously. The engine seems to love it, and by what I can see I have no leaks using a fully synthetic oil.

I've noticed lately that my engine seems to burn more oil than usual, even though I still have NO smoking from the exhaust or abnormal residue inside the pipe... or is it? I ran 5 qts of Mobile 1 and a qt of Lucas last oil change (1200-1300 miles ago), and so far I have put about 1 1/2 qts of oil in it. But here's the strange thing.. I checked my oil this morning and seemed to be a 1/2-1 qt low. I put the remaning half qt of oil I had in, drove it to college and back, let it sit for about 20 minutes, anc checked the oil again. The reading on the dipstick was actually HIGHER than the reading when I first added the oil (but not overfull. Just more in the safe zone). I checked two more times, same reading!

So, I guess my questions are:

1) What could cause this wierd oil leveling?

2) If I am burning oil more than usual, would it be safe to run 10w40 rather than 10w30 to try and help the old rings/ seals out? Btw, oil pressure is still great 22-25 psi at hot idle, 30+ psi at 1500 rpm, 40+ highway.

3) I've noticed again that I have a residue on the end of my dipstick, about 1/8-3/16" of the way up. It isn't white, but like a chocolate color. Before anyone yells headgasket (like I feared), I have NO coolant loss anywhere. Coolant level in overflow is consistant, and coolant in the rad has no brown residue or what not. I am thinking condensation. I drive city a lot when its cooler, with shorter trips and then drive about 25 miles to LFCC and back Mon-Thur. Plus, the weather in VA has been wack. Hot one day, really cold the next. I know these temperature variations can cause condensation in any system. Ideas?

Thanks for any help!!

 

I hate to state the obvious, but I'm sure you know that oil expands when hot.

Some oil consumption at these miles is normal. Since everything else seems to be OK according to you, I would check the oil every 2 tanks of gas or 500 miles.

Even if you have to add 1 quart every 1000 miles, that isn't excessive.

I wouldn't change to 10W40. It just makes your engine work harder.

 

....wow. I am an idiot. Thank you for stating the obvious, or else I woulda stayed totally oblivious to my ignorance.

Also, it really makes me feel more confident to know that my consumption isn't catastrophic. Thank you!

 

A quart in a thousand miles is still in the normal range by 1991 standards, just keep doing what you've been doing, you'll be ok for a long time as long as there is oil in the engine.

 

I was just trying to give an explanation of what you were asking in question #1. Sorry if you didn't like it or took offense to it.

I don't know what you may or not know.

Example: The first question you have to ask when someone says their vehicle won't start: "Has it got any gas?".

 

No, really. I took no offense. Had you not of mentioned that, I would have never thought about it. I am totally serious when I say thank you!

 

I am sure half my oil consumption is leakage. Perhaps you have some leaks also, especially if you are not seeing a lot of exhaust smoke. Could explain where some of the oil goes.

 

That's another thing I prob shoulda mentioned. I seem to have no leaks (knock on wood). I had one a few months ago, but after replacing the VC gasket it went away. Oil filter adapter o-rings were replaced just a few weeks ago, no leak there. Rear main hasn't been leaving any spots. So far, so good on leaks (again, KNOCK on wood!).

 

second example: first thing you ask when someone says their laptop won't start: does the battery have charge?

 

Sometimes it turns out to be something as simple as that. I honestly would not have thought about hot oil had he not of mentioned it.

 

You're welcome. On the internet, it is difficult sometimes to read the meaning behind the words. And sometimes, people take you wrong in what you type.

Best of luck with your Jeep. I'm not convinced it has an unusual problem, considering the age and miles.

Sounds like you drive it enough to evaporate any condensation.

 

Have you looked in the fill hole to see what the head looks like? Might be some blocked up passages keeping oil from draining back fast enough.
IIRC, Synthetic oil doesnt leave the blue smoke like dino. You could still be burning it.
I would stand behind it at op temp (maybe after a ~50mi drive) and see if you smell burning oil. Smell at idle, and then have someone get in and put it in D and go to about 1200 rpm (load the engine).

1qt/1000 isnt bad, but my 97 with 280,000 doesnt burn any at all and neither does my girlfriends 230k+ motor.

 

Thanks for all the help/ advice guys! I will do the "sniff" test tomorrow!