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I am having a very difficult time finding a leak...and mor importantly, determining its importance.

When I bought the car 3 years ago I was told it had a small oil leak near the front. Sure enough, for the past 3 years I have a well developed oil spot on my garage. The think is, it never loses any more than a quarter to half quart--if that--between oil changes. Car has 138k miles.

There is a smoke smell when the car warms up, and if you look closely with the hood up, you can see light smoke billowing, but I can't tell from where. It's not near the valve cover.

People I know ask me about the "rear main seal." I can't for the life of me find it--on the internet, or where it may be positioned in the car...even though I know about it from other cars.

Any ideas?

Sounds like oil is leaking on to the exhaust mani, check your distributor seal since you're sure its not the valve cover.

Rear main seal is between the engine and the transmission, specifically between the flywheel and block. If it were the rear main seal I doubt it would smoke, rear main seal would have the oil fill up in the transmission bell housing by the clutch, pull off your starter and maybe you can find something to peak into it to look for oil.

I doubt it's the rear main.

I think you have a couple of problems going on here. Either high mileage and your rings are a bit warn and or the more common issue with the 4 cylnder models is the valve guide seals. Which you can only notice "usually" during start up while cold and or getting on the throttle really heavy. That would cause you to burn very little oil. Also check your PCV valve, if bad it will allow oil up into the intake and you will burn some as well as it will gunk up the intake.

With the leak the front main seal is known for being an issue. It is behind the crank pulley. It is kind of a pain in the butt to change but you can do it while the engine is in the car. You need to determine where all the excess oil is so the key points to check are:

- The front main seal
- The rear main seal (how you can do that is see if there is seepage in between the engine and transmission)
- The distributor seal (as mentioned above this is also known for going bad)
- The camshaft seals and or the valve cover gasket
- And the oil pan (sometimes if someone scrapes it on something they can leak or just from being old, also check your copper seal on the drain plug)

You need to find the source before you can determine what the issue is. chances are it is not the rear main but could be any number of the others.

Hope that helps

A poorly tightened oil filter can cause drips onto the exhaust piping.

I have a transmission front seal leak. If your car is anything like mine then years of accumulated oil and road grime probably coat most of the lower engine and transmission surfaces.

Then you go driving and wind blows the grit and grease rearward, creating a pathway for oil to travel along, and eventually it will drip off far from the source.

If you clean the bottom of the car really well it will be easier to spot where the leak is coming from.

Flow will intensify now that there's not a crusty dirt bandaid holding it back... but you'll see its origins better.