What would cause a rear main seal to leak?

The most common cause of rear seal leaks is age and/or high mileage. The seal can also leak due to the vehicle being stored for an extended period of time, or from running the engine low on oil. This causes drying and hardening of the seal leading to shrinking, cracking and tearing of the rear main seal.

What are the symptoms of a rear main seal leak?

The main symptom of a rear seal leak is when your car starts leaking engine oil at a faster rate. If your vehicle has started leaving black puddles on your driveway or parking lot, something is definitely wrong with the situation underneath the vehicle.

What causes a leak in the rear main seal?

Since rear main seal leaks are uncommon on most vehicles it’s very possible that you’ve got another leak higher up on the motor that is dripping down and just looks like a rear main seal leak.  The most common leaks that can masquerade as a rear main seal leak is a valve cover gasket leak, intake manifold gasket leak or a distributor gasket leak.

How to fix a rear main seal leak in a Chevelle?

Drain the oil, remove the oil filter and dipstick , and drop the exhaust pipes from the manifolds (or unbolt headers from pipes). Remove the flywheel dust shield and remove the fuel pump and plug the fuel lines. Rotate the crankshaft so the timing mark on the balancer is in the 6 o’clock (very bottom) position.

Where is the oil pan gasket under the rear seal?

 The oil pan gasket is just below the rear main seal. An oil pan gasket is also usually much less expensive to replace so it’s important to check for leaks in your oil pan gasket before you jump to any conclusions.

Can a 350 SBC rear oil seal leak?

There is a rear cam bearing also that can leak. It is rare but it does happen. Line honed mains on your 350 won’t cause loose seal issues unless somebody did something wrong. After all the line hone should restore the factory bore spec after the caps are clipped.