I have a D16A6, that has some sort of ghost in it... I have just started driving the car after cleaning it up. I took it on a 80 mile trip and it drove great, no over heating, strange sounds, but a tiny amount of white smoke at high RPMs before shifting gears. I was not to concerned about the smoke since is was so light, but decided to check the oil levels before taking it to school the next day just to be safe, and good thing I did!!! before the 80 mile drive the dip stick had oil right below the max fill line, and in the morning it did not show anything on the stick.. where did this 3 1/2 qts oil go? checked the radiator, its clean green. filled it back up with oil and it has sat a week in my garage, and there are zero leaks under the car. I am picking up a compression tester this after noon to test the engine. Any ideas about what it could be? Just incase I am forced to pull the engine to attempt my first rebuild, I picked up a "running" D15B7 long block to drop in while I fix up the A6.

 

best guess is oil getting past the rings. it does seem to be a large amount, but a hone job and set of rings really isn't so hard or expensive. worth it to try IMO

 

can a compression test diagnose that, or do I have to tear into it?

 

A leak down test can tell you which is more worn. valves and or cylinder walls/rings.
I don't know what's involved in this test though. But it's what I read.

 

 

compression test will show a leak
But you won't be able to distinguish between the valves or rings being the culprit.

 

How many miles?

Probably a combination of bores being worn right out and valve guides being hot dog down a hallway.

 

You need compression and leak down tests to figure out what might be going on. White smoke is typically antifreeze. But, you probably have a bad oil control ring(s). That will cause it to burn oil at high RPM but not necessarily smoke much at all during low RPMs.

 

Getting ready to do a compression test now, and starting a build thread :D First sign of bad juju, number 4 (closest to the dizzy?) has what appears to be rust built up on the threads. no sure what it means..

 

I see a rebuild in that engines future, lol. The compression numbers you posted on that other thread - the high numbers are low. So, yeah.

 

anecdotal: I've seen oil rings completely packed with carbon at only 130k miles from an otherwise healthy motor with good compression test results. it only used about a qt between changes but after a thorough cleaning and some fresh rings it's gone 100k without using a drop.