After driving my '95 3.0 4x4 PU for the past 110k miles (I'm at 178k total), I think I've partially figured out my oil consumption issue. But the larger question is WHY?

Here's the deal:
When the oil is at the full mark on the dipstick, I drive 500 to 1,000 miles and I find that the dipstick is at 1/2. My normal routine would be to add oil and keep going. Over the last few months I decided to see how long it would take to get down to the low mark. Well, after 2,000 miles, it's been sitting happily at the 1/2 mark. I added oil to the full mark, drove to Chicago and back (about 400 miles total) and the dipstick is reading 1/2. I'm very careful about being consitent in my oil readings. Same place, waiting 10 minutes after parking.

So why is this? At an oil change I add 4.8 quarts with a new filter. Goes right to the full line. Why would it lose 1/2 quart and then stabilize? There are no oil leaks on the engine and I'm not visibly burning oil. I'm running Mobil 1, though I saw the same behavior with Amsoil.

Any ideas? Anyone else experience this? I'm not worried about issue, just wondering why.

MadCityRich
'95 3.0 PU 4x4
4.88 gears
big rear bumper
tasteful scratches

 

do you fill the oil filter with oil before you put it on? It will suck down about half a quart just for the oil filter.

 

Won't account for what he's seeing, as he adds oil to bring it up to the fill mark and then it drops 1/2 again, etc.




Fred

 

If it's not leaking, it must be burning.
I would check compression in cylinders and take a look at spark plugs while you do that.

 

Don't foget if your crank case beather is plugging up, and or you have to much pressure in the crank case ventilation or overfill the oil, It will blow into the intake hose. This is most likely is were that oil is going, and it gets burned up in the combustion proccess. Turbo motors burn oil this way. Take off your intake hose and look in there to see if there is a light coating of oil. mY 92 3.0V6 has this from were the crank case ventilation tube dumps into the intake hose. It's normal part of emissions.