Where does all my oil go?
woodi
Wagonist
So I am starting to get frustrated and lost with this and am not sure where to look next. I have a DOHC ZC I swapped into my car last summer. The engine runs fairly well but devours oil. Say a quart every 1000 miles or so. Shortly after I did my swap I noticed blue smoke on startup so I figured my valve stem seals were bad and must be what was causing my oil loss so I replace them without removing the head. Now no blue smoke at startup but oil still disappears way too fast.
I checked compression and get 170-180psi in all four cylinders. Replaced the PCV last summer trying to troubleshoot some other issues.
I've crawled all around looking for leaks and haven't found anything. I replaced the rear main seal before putting the engine in and can't see any other obvious leaks.
The other day I came down a long hill engine braking in third gear to a stop sign at the bottom. Accelerated out of the stop sign and dumped a big cloud of blue smoke. That makes me pretty sure that I'm burning the oil not just having it drip out of somewhere but how could it be getting in there? Oil gets pretty dirty and black looking quite quick as well. Even though I still have good compression could my oil seals just be shot? Any ideas as to how it could be leaking into the cylinders? I've pulled the sparks plugs and none of them look particularly bad either. I'm getting stumped.
I checked compression and get 170-180psi in all four cylinders. Replaced the PCV last summer trying to troubleshoot some other issues.
I've crawled all around looking for leaks and haven't found anything. I replaced the rear main seal before putting the engine in and can't see any other obvious leaks.
The other day I came down a long hill engine braking in third gear to a stop sign at the bottom. Accelerated out of the stop sign and dumped a big cloud of blue smoke. That makes me pretty sure that I'm burning the oil not just having it drip out of somewhere but how could it be getting in there? Oil gets pretty dirty and black looking quite quick as well. Even though I still have good compression could my oil seals just be shot? Any ideas as to how it could be leaking into the cylinders? I've pulled the sparks plugs and none of them look particularly bad either. I'm getting stumped.
Comments
Sounds like rings to me
The good side is that for now you don't need to change oil except for the oil filter at each interval.
Have a friend follow you around to see if blue smoke comes from the rear @ the stop signs.
Good Luck
I never really thought of it like that!
I thought that once and the oil that didn't burn stayed in got really nasty and mixed with the oil I added Started wearing things out fast.
Now, take about 1 oz of oil per cylinder, and drop it down the spark plug holes. Do the 1st cylinder, and then turn the engine over for a couple seconds. Screw in your compression tester, and do the test over. Before you crank the engine for test #1, put your 1oz of oil in #2. This way it'll get spread around while #1 is being tested. Repeat this for the other cylinders. If you get a substantial increase in compression numbers (25-50 psi) then you'll have a pretty good idea that it's the rings.
You might think "my compression numbers without doing it this way are pretty high", and it does sound to me like they're pretty good numbers. What you may not know though is how accurate your gauge is. It could be reading high. This test will show the improvement (or not) from better sealed rings.
Maybe I put too much oil in. I just poured a little down the spark plug holes...not much. But when I was hitting the button on the side of the compression tester to let the air out oil was spurting out too.
So I changed my oil which needed to be done and added some auto-rx engine cleaner (which I did lots of reading and reaserch on and may help me out if my problem is in fact stuck rings not just completely worn out rings). We'll see how that goes and hopefully it'll help things enough to get me through the winter. Once it warms up in the spring I can start thinking about rebuilding or swapping again.
Oh and on one final note when I started her back up after the oil change last night with the oil I dumped down onto the pistons she was a smokey mis-firing mess until I took her for a run around the block and blew it all out.