Very Thin Oil - What can cause this?

[RickO]

I bought a 1999 Mitsubishi Montero yesterday and was changing the oil today and noticed it was very, very thin. Like has something in it besides oil, thin. It didn't even run out evenly like oil - it gushed out like gas. I knew immediately something isn't right. Am I over looking another fluid besides gas that could be leaking into the oil. It is a manual Tranny also.

It did not smell like it was antifreeze and it did not look milky. just very thin. My rototiller had a float issue and was getting gas in the oil this past summer and this oil I drained from the SUV today looked exactly like that. Smelled kind of gassy also.

... .So assuming it is gas, what can cause gas to get in your oil. Fuel injected 2.4L four C.

I checked the radiator and it is not low and it is very green and looks like what it should - even tested it and it floated all the balls to -40.

Any help would be appreciated

 

[Egon]

Check what the oil looks like after the change and some mileage.

 

[alchemysa]

Ive got a Pajero 3 litre V6. I think thats pretty much the same vehicle. I can't really imagine how gas could get into the sump.

 

[SPYDERLK]

It might just be a 0W oil... Thinner than youre used to. Try torching a little of the drain oil. If it burns readily after you light it it has some gas.
larry

 

[Willl]

What was the oil temp ?

 

[Reg]

ONE possibility would be flushing oil, though why someone would LEAVE that in is a bit puzzling.

If it was a big ole V8 with hydraulic lifters I could (half) understand someone trying flushing oil to loosen up a noisy stuck lifter,,,, hmmm, I doubt that it has hydraulic lifters, though the previous owner might have seen his Pappy put flushing oil (or diesel fuel) in to fix "engine noises" (-:

Are there any symptoms that the previous owner might have been chasing ?

Yeah, I'd run it for five miles and see how it looks.

 

[RickO]

ONE possibility would be flushing oil, though why someone would LEAVE that in is a bit puzzling.

If it was a big ole V8 with hydraulic lifters I could (half) understand someone trying flushing oil to loosen up a noisy stuck lifter,,,, hmmm, I doubt that it has hydraulic lifters, though the previous owner might have seen his Pappy put flushing oil (or diesel fuel) in to fix "engine noises" (-:

Are there any symptoms that the previous owner might have been chasing ?

Yeah, I'd run it for five miles and see how it looks.

..HMMMM, now that you mention it.. It does have a bit of what I think sounds like a lifter tapping at hard excelleration. nothing I was really worried about because it isn't that bad. Maybe they were trying to fix that.

I've never heard of flushing oil but I will say, I put Full synthet and it is very clean on the stick... so I if it was a flushing oil it did a good job. I was planning on taking it for a good long drive tomorrow. and will keep checking the oil.

 

[Matt_Jr]

If it doesn't smell like gas, then it's probably just a low viscosity oil like 0w20 or 5w20. If it does smell like gas, you have a bad coolant temp sensor, leaky injector, or an injector wire to the pcm shorted to ground, or a bad pcm. Antifreeze causes it to thicken up and turn milky. My guess is you changed it while it was hot too. Don't worry about it. Just look in the owner's manual and put the right stuff back in it. Next oil change, report back and let us know what you find.

 

[RickO]

If it doesn't smell like gas, then it's probably just a low viscosity oil like 0w20 or 5w20. If it does smell like gas, you have a bad coolant temp sensor, leaky injector, or an injector wire to the pcm shorted to ground, or a bad pcm. Antifreeze causes it to thicken up and turn milky. My guess is you changed it while it was hot too. Don't worry about it. Just look in the owner's manual and put the right stuff back in it. Next oil change, report back and let us know what you find.

I drove about 100 miles today and checked it again after it sat for a couple hours... same level and color and smelled like oil. Maybe it was just some real light weight oil seems normal now.

.. anyway thanks for the comments.

 

[Western]

I had a friend that bought a pickup years ago, same problem. He and I went over to the residence where he bought it to see if we could get some mechanical answers about the thin oil. The resident was gone but the neighbor saw us and asked what we where doing, my Buddie explained it to him and asked if he could pass along his concern to the previous owner, (way before cell phones) turns out the seller and his neighbor put transmission fluid in the oil to "tighten the rings"...go figure