In the course of cleaning the flame trap, I just repaired a vacuum leak in the small vacuum line numbered 14 in the attached schematic. Can anyone explain the function of this line, and what problem a vacuum leak would cause?

The engine was leaking oil from the filler cap, which was replaced by my mechanic. I was checking to see if the leakage was exacerbated by a clogged flame trap when I found the leaking vacuum line.

Is there any easy way to confirm the proper function of the oil trap (Part #3)? Are there other possible contributing factors to oil leaking from the oil cap? I should note that replacing the cap so far seems to have eliminated the leaking. The car was losing about a quart of oil every 250 miles, with no signs of burning oil.

 

Not sure what the line does, but issues with any of the vac lines does mess up the computed test monitors, makes SMOG cert difficult and can actually cause engine damage. My parts DVD stopped working, so I don't know what #15 connects to. The filler cap seals do need to be replaced, but I've never seen mine cause anything like 250 miles / quart.

 

The car has now traveled 250 miles since the seal was replaced with zero oil consumption, so the seal appears to have been the culprit. Symptoms were a fair mimic of a bad rear main seal. Oil leaked from under the filler cap and ran unnoticed under the aluminum cylinder head cover within a channel to the back of the cylinder head, and then down the back of the engine block. While in motion, there is no sign of a leak, but there would always be a puddle of oil under the block/transmission seam when parked overnight.

 

Glad the filler cap gasket solved the problem. You can get a similar issue with a leaking right camshaft rear seal.