Oil leak sealant?

[mestrezat]

Back in the US, in the good old days, if you had stuff to stop all kinds of leaks on engines. The diesel engine on our boat(Ford Lehman 80HP) has developed a leak on what appears to be the back left side. Not sure where but we are looking since the leak went from minimal to problematic over the last two days. We're leaking a good pint during a 50 mile stretch of running her.
When I had a car with a gasoline engine, there was stuff you could add to your oil that would stop oil leaks. Not a perfect solution but I used it and it has worked, at least until I could actually afford to get the engine fixed.
Does something like that exist for diesel engines? I have a bad feeling that the seal at the rear end of the crankshaft has sprung a leak and if I'm right, it's going to mean tearing down the engine to get at it. As we had already left Thailand for the Maldives and had to turn back, I don't want to spend the rest of the season where it's better to get out stuck here as much as we have enjoyed Thailand.

[atoll]

better to fix it sooner than later!
not much between Thailand and south Africa!
getting stuck in the maldives could be very expensive.
the oil addative for petrol engines is the same as for diesels,though for a failed lip seal not sure how effective it will be.
wynn's make something,best google for what is available locally.

[GordMay]

Originally Posted by atoll

better to fix it sooner than later!...
... best google for what is available locally.

Never used it, but FWIW:
➥ PermaTech - Fast and Easy 2-Part Head Gasket Repair Sealer- Oil Stop-Leak Sealer Page

[rognvald]

Mes,

In my youth, I had the great fortune to befriend an old German mechanic that worked most of his life on cargo freighters and could fix anything from lawnmowers to ship engines. I once asked him about an oil additive that claimed to fix rear main seal leaks since I had one on my old Ford Falcon convertible with an inline 6 cylinder engine. His reply was simple and straightforward: "I've never found a mechanic in a bottle." Good luck and good sailing.

[Tellie]

Originally Posted by rognvald

Mes,

In my youth, I had the great fortune to befriend an old German mechanic that worked most of his life on cargo freighters and could fix anything from lawnmowers to ship engines. I once asked him about an oil additive that claimed to fix rear main seal leaks since I had one on my old Ford Falcon convertible with an inline 6 cylinder engine. His reply was simple and straightforward: "I've never found a mechanic in a bottle." Good luck and good sailing.

Agreed!
Anything that can be added directly to the oil fill that will stop a main seal leak will also have the potential stop a lot of other things flowing where they should flow to. Atolls advice is the best.

www.HaldenMarineService.com

[darylat8750]

There is no "fix in a bottle" for oil leaks.

First be sure it is a rear main leak instead of something easier. It does sound like it is.

The rear main seal on the old Ford conversions is the old packing type.
The material actually looks similar to the packing on a prop shaft. I don't know if a lip type seal is available now but when I had that issue with a Lehman 120 hp we managed to replace the seal without removing the engine. We just had to lift it enough to get access to the bottom. I asked Brian at American Diesel if it could be done without dropping the crankshaft and he said many have tried and failed that attempt. You will need to remove the transmission and the timing gear from the front of the engine in order to drop the crankshaft enough to get the new seal in.

[thinwater]

Most of these function by adding a swell agent that causes all of the elastomers to soften and swell. This can stop minor leaks, but it shortens the life of all of the seals. It will only work on seeps.

I wouldn't.

[sailorboy1]

aren't these on the shelf next to to the weight loss pills?

[P27]

I have never had to use this but I have been told more than once that if you have an oil leak to add a small amount to transmission fluid to the engine oil. The transmission fluid evidently causes the gaskets to swell and seal just a temporary fix but I would try as a last resort may be someone else has heard of this or tried it