It should develop enough pressure to equal a cold engine start. The seal may work OK when the engine isn't running, but when the crankshaft is turning it may not seal as well as it does then the engine isn't running.
How did it go ? Did it work?
My 87 GT has a leak 'sometimes'. Let it idle a heap and not a drop..drove it a bit and still not a leak. Mechanic said it was leaking and I didn't believe him but when i got it home it was leaking a bit. Then changed the oil and it was leaking even more...drove it for an hour or so and it was leaking even more. Cleaned it up with degreaser and hosed it off..drove for 30 min , let it idle for a further 30 min and not a drop of oil????
Could this still be a rear main seal ?
I already put in a new pcv valve and that filter below it....so doubt that is any issue.
Anyone else have a leak that seems to come on more when driving a lot and not when only driving short trips ?
I did order a UV leak detection kit and next time it is leaking I will use that but the issue is I can't get a roadworthy (australia term for safety certificate) if there are any oil leaks at time of inspection.
I only got the car a few months ago and only drove it a few times but believe the engine is in good shape as it does run well. Is the crankcase pressure just controlled but the PCV system? I changed the pcv and that filter below it.
Strange it only seems to leak when driven for a long time and iddling time doesn't seem to do anything to it.
Now this is just me thinking out loud (I know I'm not supposed to be thinking, it gives me a headache) but maybe at idle the oil is not whipped around enough to escape the seal, now add a few hundred rpms and oil flying around, crank spinning furiously and just enough room from an improperly installed or old stiff seal and you have oil escaping! do you know how old the seal is? Have you checked to see if you are building crank case pressure at higher rpms? Hold your hand over the oil filler tube to see if there is any pressure when you raise the rpms up to cruising level say 2k.
I let the car warm to operating temperature and revved up engine and took oil filler lid off and put hand over. I didn't feel anything, no suction no pressure - nada.
The car did pass a california smog check only 500 km ago and doesn't blow any smoke..
It is a very strange thing that it only leaks after long drives. If it was the oil heating up and thinning out then it should do that at idle as well.
The back of the intake is a place to look for oil leaks, most times you notice the oil around the trans bell housing after a drive, I suppose it could seep between the block and the bell housing. There are a couple plugs behind the flywheel that are connected to oil passages but they rarely leak,