Where does lost oil go???

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For the guys running an extended life synthetic, specifically Mobil1, where does the lost oil go when you have add 2 quarts over the 10,000 miles? I would have to think it's built up on the engine somewhere? Please advise. I am leery of the extended life oil change intervals even with a filter change at 5,000 miles. Thanks.
 
Yep, if not leaking on the ground its going out the exhaust.

Now the question comes back to acceptable oil burn, in 8 to 10,000 miles even the tightest motor will normally use a 1/2 quart or so.

Then you have loose motors that may burn a quart every 3,000 miles. That or any worse I consider an oil user to an oil burner.
 
It's over a 1000 degrees in the combustion chamber and there is a thin coating of oil on the cylinder walls that gets vaporized in the process.
 
Originally Posted By: bubbatime
It's over a 1000 degrees in the combustion chamber and there is a thin coating of oil on the cylinder walls that gets vaporized in the process.


Sounds like the NOACK test testing at 250 is pointless if it is a 1000 degrees...wow just...
 
Originally Posted By: Mackelroy
Yep, if not leaking on the ground its going out the exhaust.



I think that sums it up nicely. However the engine comes to burn the oil, whether via rings, valve stem seals, or PCV carryover, it ends up going out the exhaust.
 
I think lots of it must end up on the ground. Look in the spaces in any parking lot. Also, look at any dip or irregularity in a city street surface. There are always dark patches where some automotive fluid was shaken off.
 
Surprising the amount that gets caught up in the PCV flow. Lot of oil in misted form from agitation inside an engine. I have a PCV oil catch can on my pickup engine. In 10,000 miles, I have only used, maybe, a quart. In that same time frame, the PCV oil catch can has captured almost 16 oz of of junk out of the PCV line from going to the intake. Can only imagine how that would have looked coating the intake valves, etc.
 
Usually it's bad valve-stem oil seals but could also be rings in engines that are in really bad shape. It could also be the PCV line if the PCV valve is stuck or you overfill. Then there are leaks.

Base oil burns and gets out of the exhaust but some of it becomes varnish and gunk. On top of that the metal additives (detergents, moly, etc.) don't burn and form oil ash. Some of the oil ash permanently remains in the cylinders and on the spark plugs. Also, some additives, especially ZDDP, are poisonous to the oxygen sensor and catalyst, and reduce their lives. With diesel particular filters (DPF), ash going through the exhaust end up being caught in the DPF, eventually helping to clog it. For that reason, for DPFs, they require newly introduced low-SAPS oils (ACEA Cx categories) that are not readily available in US as there are few diesels here.

1 qt in 5k miles is a little high but not bad at all. I would have liked it to be less than 1 qt in 10k miles, but hey, everything in life experiences wear and tear and therefore slowly but constantly ages.
 
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