Oil stop leak products - which one works?

I?m no expert, but I wouldn?t have thought a main bearing seal leak is going to cause significant oil consumption. Ring wear and consequent high crankcase pressure could well be responsible for high consumption and main bearing leak.

Oil additives to stop oil leaks sound like snake oil to me.

Tim

I've had cars with leaks from these seals when other things have been OK. Remember that oil is fed at pressure to the bearings, so they need reasonably good seals.

On my Velocette singles I used to route the oil tank breather (which vents crank-case pressure) into the primary chaincase. Some mist would find its way out on to the front sprocket of the rear chain, which was useful.

+1 about additives, I have never heard of one from reputable sources. In the old, old days when a lot of us were driving wrecks it was common to go up a grade or two to reduce consumption. One source of consumption was oil being sucked down worn inlet valve guides; there were no seals there in the old days.

Pulley side or flywheel side? I assume pulley end.

Is it not possible to drop the engine down slightly for access to the pulley and pulley seal?

I didn't know they even existed!

No such luck. It's dripping from the bell housing. As it's an automatic there is no issue having oil on a torque converter.

Oh, that's a bugger.

Any chance of a drilling the housing and adding a pipe fitting, pipe and pump so you can re-use the oil? :-)

I have used one of those seal expander fluids on power steering with limited success. Didn't stop the leak but reduced it.

Interesting. I can see how something that softened and increased the elasticity of a lip seal that had become hardened by temperature might work. My impression is that you don't see as many hardened seals as you used to (or as many oil leaks). I suspect manufacturers are selecting higher performance rubbers as people have become less tolerant of leaks. (As an aside, the reduction in oil consumption from better bore finish and ring design over the past 50 years is astonishing, to my mind).

Think the big difference is cars no longer have cast iron blocks with the pistons running directly in that. Either liners made out of much better steel - or of course chemically treated ally bores.

Much the same as the cylinder heads. You don't need routine valve grinds these days either - unlike when they were cast iron. And I've no doubt modern oils help too.