Mysteriously disappearing oil?

[idlewild]

Hey all, I have a 2000 Ranger with a 2006 engine in it (engine has about 40k miles on it, truck has just over 140k)... anyway, ever since we put in this engine a year and half ago I've been having off and on problems of there being less than the desired amount of oil when it comes time to change the oil.

Sometimes it's low, sometimes it's not. But recent events this weekend has me baffled...

Two days ago when I came to a stop and the truck was idling in drive the oil gauge would drop, but pop right back up should I either accelerate or drop it into Park.

Took it into Jiffy Lube to get the oil changed and they told me the oil was low, "off stick" was the term they used. They changed the oil and also did a flush/cleaning to clear any sludge out of there. Also replaced the oil filter.

But... today after driving highway speeds for an hour (not together, half hour one way, an hour to cool, and half hour back) the oil gauge was dropping again when idling!!

I got home and pulled up the oil stick, I'm having a hard time seeing as the oil is new and clear, but it does appear to be very low.

I am NOT smelling oil burning at all, there is absolutely no smell. Where could the oil have gone? My dad suggested that the new oil filter might have soaked some up... but my boyfriend disagrees.

I know very little about engines, I know enough to check the oil, radiator fluid, change the air filter and fill the washer fluid but that's about it.

Will be taking it into my auto repair place on monday... but any ideas of what the problem might be and where this oil could be disappearing to... and how much it might cost to fix it.

Thanks in advance!

[BernieB]

If it's not burning it then it has to be leaking. Put a large square of cardboard under the front end when you park it overnight and see if you're getting any drips.

[Cereal Killer]

I agree with Bernie if your not smelling it burn or seeing burn its gotta be a leak

[leolkfrm]

sucking it in the PVC valve a litle at a time....

[Case 7230]

How many miles do you do between oil changes? Do you add any oil between changes?

[idlewild]

Originally Posted by BernieB

If it's not burning it then it has to be leaking. Put a large square of cardboard under the front end when you park it overnight and see if you're getting any drips.

Originally Posted by Cereal Killer

I agree with Bernie if your not smelling it burn or seeing burn its gotta be a leak

Just checked underneath it, it's been parked all night. No oil on the ground, two teeny spots but who knows if that's from my truck or the previous car that parked there. It's rarely parked in the same spot twice since it's free for all parking at my apartment. I'll put a piece of cardboard underneath it tonight to see if anything shows up... but I checked the entire lot just now, in all the normal places I park, no large, fresh oil stains. Could it be leaking while running? I've noticed it the gauge only starts dropping after long periods of highway speeds.

Originally Posted by leolkfrm

sucking it in the PVC valve a litle at a time....

Could you explain more? What's a PVC valve

Originally Posted by Case 7230

How many miles do you do between oil changes? Do you add any oil between changes?

I go about 3,000, but with my busy schedule I often don't get it in (or catch the mileage) till about 4,000 miles... bad I know. And no, I don't add any oil between changes.

My boyfriend is going to come over and look at it, he wants to start it and see if any smoke comes out the exhaust. He said that white smoke would indicate burning of radiator fluid, black smoke burning of oil. Is he correct?

Oh, I don't know if it means anything, but the radiator fuild has dropped a quite a bit over the past couple of months, topped it off with the change. Is that normal or abnormal?

[silverhairdeere]

maybe bad valve seals for the dispearing oil and a leaky head gasket for the antifreeze .

shd

[hotrodpc]

I'd say you are burning the oil and its in such a small amount at a time, you don't THINK its burning it. I'd be willing to bet a 2 liter of Pepsi, that if you took it somewhere and put a sniffer in the tailpipe, you would then see its burning some oil with high readings. 2 good points above. #1, Leo mentioned it, and its a cheap fix and maintencance anyway, so I'd replace the PCV Valve. Although, that may not make a change anyway since the blow by in the crank case is going to get to the PCV valve no matter what. Do you have baffles in your valve cover where the PCV valve goes? If not, if you are having a high mileage engine burning oil problem, baffles do help. 2nd. SilverHD mentioned valve seals above. Which would mean you could likley be burning oil only when you first start it up, then the oil burns off in the first 1 or 2 miles of driving. Unelss the valve seals are very bad, and along with valve guides will make that problem even worse, so you could be burning a little bit at a time, and not enough to smell it or see the smoke out the tailpipe. Then of course, yep you could be leaking it, but in MOST cases that is noticeable somewhere but not always. It chould be sticking and building up on a dirty part of the truck underneath, so the dirty is absorbing the oil and its not getting a chance to leak. If you are losing this much oil in between changes, I much doubt that is your issue. I'd be thinking the PCV vlave, and Valve seals/Valve guide suggestions. But now you know, check your oil frequently. Say every time you fill the tank, check and add as necessary. That dip in the guage you are talking about it normal for low oil and bad actually. Everytime you see that dip to 0, that means the oil pump is not picking up oil and supplying the bearings with oil. Makes for a very short lived bottom end in the motor. If it still runs good. Run it, just be sure to keep the oil level correct.

[bradrhale]

PCV positive crankcase ventilation or valve. i have heard it both ways.

[hotrodpc]

Ventillation??? I think I have heard of it reffered to as that before too come to think about it. Bit it actually is a valve. Since it allows air one way only, but not the other.