Noticed a bit of oil on the garage floor in a werid spot tonight after I took my Cutlass out for a drive. It's leaking down onto the transmission cross member on the passenger side. I crawled under the car as much as I can and can't figure out where it's coming from. There is no other leaks or signs of oil that's been sprayed onto the floor pans. Anyone have this issue before?

1971 Cutlass S car 350 Rocket with a 200R4 trans.

 

The intake manifold gasket can leak - often it's one of the corners. Difficult to spot on the rear of the intake manifold, but the corners are common areas of oil leaks. The main bearing seal at the rear of the engine is prone to leak - the seal is made of rope, over 50 years they have a tendency to loosen up after having been saturated with oil for such a lengthy period. One of your best ways to get a handle on the leak is to do your best to wipe down all areas where you suspect leaking and isolate the leak as either transmission oil or engine oil; albeit, it's best to perform this test on one system or the other rather than both at the same time - although you could perform them both at once.

Buy a small container of fluorescent engine oil dye available at nearly all automotive parts supply stores - buy a small pen-light UV flashlight if you don't have a UV light. Add the dye to the engine oil, go for a good 30 minute drive. Using the UV (black) light - IN THE DARK - attempt to visualize the fluorescent dye. It will demonstrate tell-tale signs of leakage. Good Luck. Do the same with the transmission if you suspect it's transmission oil.

 

It's probably transmission fluid possibly coming from the dip stick tube gasket.

 

Thanks for the response. I will look to pick up some of that dye. I'm going to take it out to my mechanic first. I just had a new transmission put into it. The engine was rebuilt last year and there hasn't been any leaks since the one I noticed last night.

 

Thanks. I double checked this morning and it's definitely motor oil.