Engine and Transmission Tech

EDIT: Probably useful to state that the engine being use is a 3.9L block - buick 300 crank

(Sorry this is so long). I just seem to keep running into problems, so I'm coming here for advice again(you guys have never been wrong!)

I worked out all the small issues I've been having and was hoping to break in the engine today. About a week ago I removed the fiberglass flywheel cover(bought from D&D for use with a BW t5) to show a friend how the HTOB was setup - I guess its a good thing I did this because I noticed a very small amount of oil in the bottom of the cover.

Tonight before I went to break it in I decided I should turn the engine over a few times before starting it, just to double check for leaks. I removed the flywheel cover and sure enough about 1-2ounces of oil had accumulated in the cover. At this time it was late and I was frustrated so I called it a night.

I'll probably end up back out there tonight because I can't sleep with this worrying me haha - I'm just wondering how one can tell if the oil leak is originating at the oil pan seal or rear main seal. I did a quick visual inspection but couldn't quite tell. I'm hoping its just the oil pan seal as I start school in two days and don't know when I can pull out this engine.

Also - The 1-2oz of oil wasn't all that much but that was simply after sitting for a bit and few turns of the key - I'm worried that even 5-10 minutes of driving could cause some significant oil loss.



Edited 1 time(s). Last edit at 08/23/2011 10:18PM by RobertE.

First, does your 3.9 use a neoprene rear seal? I'm going to assume it probably does. 1-2 ounces is quite a bit of oil, more than I would think the bellhousing would hold unless it were sitting at a pretty good angle. But regardless, you really have two areas to check. It's not real likely a pan leak would end up in the bellhousing unless the cover is made in a way that directs it there. (sits below the lip of the pan for instance) And, it's not likely to leak just from sitting. But oil can leak from the oil galley end plugs, the freeze plug at the end of the cam journals, the crank seal, and the pan. The rear main cap also has to be sealed to the block to prevent an oil leak and this is a common source of leakage.

It's always difficult to get this far along and have to do something over. But just remember, if it's worth doing, it's worth doing twice. You have to expect a few of these type things to happen.

Don't disregard the transmission. If overfilled it can leak out the input shaft.

JB

Jim's on the right track Robert,
Many more things than the pan and rear main can leak into the bell housing.
Right off the bat you need to identify the fluid. Is it engine oil, trans fluid or possibly brake fluid from your HTOB.
With several ounces showing up so quickly could it even be coolant?
With the engine sitting, a pan leak is unlikely as the oil level is below the gasket. Unless you have the engine over filled. But even then it shouldn't really leak.
With a mix and match engine the possibility of a wrong dipstick is pretty high.
If it is determined to be engine oil. Try pressurizing the oil system either by spinning up the oil pump or if that is not possible plumb a line into the oil pressure gauge fitting and pressure it up with a small garden sprayer filled with engine oil.
This way you can check for external leaks without running the engine. (the sprayer also makes a great prelube tool for new engines)
Hope that helps
Fred