My 1994 ford taurus leaking oil - what is the best additive to help stop this leak

Depends where the leak is from. If it is a rotating seal like a rear main or similar, I would try AutoRX.

If it is something like a valve cover, you migh temporarilly seal it with a crude seal swell additive from your local autoparts store.

If the leak is less than 1qt/1000 miles or so, I wouldn't mess with it at all (I espicially wouldn't use any seal swell stop-leaks).

The upside to AutoRX is that it has an overall benificial effect, and they are nice to deal with if it doesn't fix your problems.

I am not sure where it is leaking - but I have tried going from 5W30 to 10W30 and it still is leaking - I have a puddle under the car is all I know - if just oil pan leak or seal - would Auto Rx hurt it at all?

The best thing you can do to stop oil leaks, is found where it comes from and replace the seal/gasket. Additives modify certain fluid properties, do not solve mechanical problems.

I agree that in general replacing the gasket or seal is the best policy. However, I've been convinced that ester based cleaning products can, perhaps 60% of the time fix rotating seal leaks. I would probably degrease the enigine some and look for the leak source, or even use the UV dye...but that's just me. I would also consider snugging up all of the valve cover and oil pan bolts if accessable. You didn't say how much it leaks?

I am more familar with AutoRX than the other similar products on the market, and they also happen to stand by their product pretty well. On the downside, I think it runs something like $20 a bottle (that's if you get the discount for being a member of an internet oil discussion forum, which I think this forum should count).

Oh, if it turns out that you had a leaking pan or valve cover gasket, the AutoRX will have only improved the internal condition of your engine in the process.

how much does it cost to replace all gaskets by local mechanic - maybe chepaer to get a new car.....

Jimjohn,
A good mechanic will find and replace the leaking gasket/seal. He would not need to replace all of the gaskets and seals, but, the only way to find out what it would cost is to take it to their shop and have them give you an estimate.

Yup...when in doubt a good mechanic should use UV dye to locate the leak. It is a fairly simple procedure and a possibility for home mechanics too.