Greetings,

I just purchased a 1995 4Runner w/147k miles. There is a substantial oil leak. At first glance, it would appear to be the rear main. The valve cover gaskets are certainly leaking.

The oil has recently been changed and the oil found on the ground is very clean. Not as dirty as one might expect for oil running down from the VC's.

I will replace the VC Gaskets and clean it up in attempts to see where the leak is coming from.

I searched on 'Rear Main Seal' and only found a handful of threads.

My question is, what's the typical life span of a 3.0 Rear Main Seal?

 

There isn't a set amount of time nor any sort of typical lifespan. 147k is about right for a seal leak.

However, the valve cover gaskets and valve covers on 3.0's are notorious leakers. The plastic valve covers warp like crazy, and the gaskets do not last 147k (as you are finding out!). Replace the gaskets, clean the engine REALLY well, and watch for leaks.

 

Ditto on the valve cover gaskets. Gravity is not your friend; a leak from the VC will travel downhill, and every leak looks like a main seal. As you (and DeathCougar) point out; you don't know where the leak is until the engine is SPARKLING CLEAN and leaking.

I think the valve cover is a pretty good design, but the gasket doesn't last forever. Read the FSM for where to put RTV when you install the gasket. Make sure the gasket surface is VERY clean where the RTV goes, or the RTV won't stick.

 

Thanks for the replies.

Toyota FIPG FTW!!!