oil ?

Scott Lusted · **Joined:** Tue Oct 27, 2009 9:52 am **Posts:** 215

OK. So I noticed this evening when changing the oil in the Jeep that it actually burned a quart over the last 6k miles.

I know this is more than acceptable but it just started this last oil change interval.

It has 121k miles on it. Ran Mobil 1 since 20k w/ 6k mile oil changes on Wix filters. Last year I switched to Quaker State Full Syn since I can get it for free from work. This is probably the 3rd oil change with QS and then I noticed the oil consumption.
I checked the other bottles in the case and they look similar to what I ran the previous change.

Pulled spark plug and everything looked normal. No oil in coolant either...

Any ideas?

Has anyone had oil consumption just show up that fast?

JamesShort · **Posted:** Fri Jun 04, 2010 10:25 pm

1qt in 6k isn't bad (besides the point..I know.....but most mfgs will say that 1qt in 1500 miles is their threshold...yes absurd I know).

Sometimes when changing oils it takes time for the engine to get acquainted to the new friction modifiers, VIIs, add pack etc....I know it seems odd to say but there are many cases of similar behavior. Just stick it out a few more OCIs and see how she handles it.

Did you make changes in the viscosity/grade?

Have you replaced the PCV valve recently?

Scott Lusted · **Joined:** Tue Oct 27, 2009 9:52 am **Posts:** 215

Yeah, I realize the consumption is well within acceptable limits but just seems strange that it just showed up.

I have always used the recommended 10w-30 so maybe this oil is just a little thinner or easier to burn off.

I am going to change the PCV when I replace the leaky valve cover gasket today. I doubt I am leaking a qt between OCI's since it is only slightly wet down the head. I've spilled a qt on the garage floor and it makes a huge mess...
Could a bad PCV valve raise oil consumption?

Thanks!
Scott

Chris Halweg · **Posted:** Sat Jun 05, 2010 7:08 am

A bad PCV can increase the leakage around seals or even blow them out. I'm not sure on a Jeep but on our Volvo you will get smoke coming out of the dipstick and oil cap seal tends to blow first and the rest will follow.

DickRasmussen · **Posted:** Sat Jun 05, 2010 7:31 am

Did the type of driving change? (i.e. more short trip around town, more high speed heavy load, more idling, etc.)

Dick (who remembers when 2500 miles per quart was really good)

Scott Lusted · **Joined:** Tue Oct 27, 2009 9:52 am **Posts:** 215

OK. So I took the valve cover off and everything looks just fine. On the 4.0 I6 it doesn't have a pcv valve to replace other than a component with a small hole to meter the flow into the intake. I'll clean it really good but it doesn't appear to be clogged. since I can blow air through it.

Driving habits are roughly the same. I did have two pulls (twice to CMP) this OCI but I did four last year without any issue.

Yeah, I think I'll just keep an eye on it. It just seems strange to suddenly show up without much warning. Did a compression check this morning and everything is rock solid. Almost factory #'s.

Perhaps it has been a gradual increase but only in the last few months have I really started checking the level since the cover was leaking.

JamesShort · **Posted:** Sat Jun 05, 2010 9:18 pm

Yes there can be large difference in viscosity in Xw30 oil. For instance M1/PP 10w30 is damn near a 20 weight (as in 500 miles of driving and you effectively have yourself a 10w20. German Castrol 0w30 is a very viscous 30 weight (12.1 centistokes at 100degC). Rotella T5 10w30 (what I use in the WRX) is also a thick 30 weight (also 12.1 cSt).

PP (pennzoil plat) is made by Sopus which makes Q horsepower so it wouldn't surprise me if Q HP is similar in viscosity.

Anyway, like I said, hold out a few more OCIs, your engine might learn to love the QHP. If not you might want to try one of the thicker 30 weight oils.

Scott Lusted · **Joined:** Tue Oct 27, 2009 9:52 am **Posts:** 215

Just as a followup to the thread I started.

As it turns out, the slow leak around the valve cover gasket appears to be the source. It wasn't a bad leak, but just anough to keep things wet. After changing the gasket, I have been 3000 miles and the oil level hasn't moved.

-Scott

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