Has anyone have experience with Oil Leak Stop additives?

[Idle]

I have a Volvo MD 2040 engine at around 3000 hrs. There is oil leakage for some time. The amount is not serious but annoying. The mechanic has seen the leak from crank posterior seal.
Will an oil stop solution help?
Can it cause any harm to other parts of the engine?
I would appreciate any advice.

[alamoana]

I would not go crazy about it. I would repair of when possible. A small leak will not be an issue as long as the oil is topped up. Good luck

[Don C L]

I don't know of any oil additives to stop leaks, and I probably would not use it even if there was one. I would agree that if it is minor, just get pack of absorbent pads and give the engine a diaper and change it and check the oil every day. Just like having kids.

[wholybee]

I have had some success with stop leak additives for automatic transmissions. Certainly not a miracle cure. It only works on very slow leaks, and takes several months to work, if it every will.

Edit:
To be clear, I mean stop leak additives for transmissions, in transmissions. I am not suggesting you use an ATF stop leak in your engine. But I might expect similar results of an oil additive in an engine.

[Scubaseas]

Lucas Engine Oil Stop Leak. Sometimes works, Sometimes not. Can't harm the engine as long as you have oil in it. Your best bet would be to replace the seal. Seen it work maybe 20% of the time on early Volvo automobile engines. Make sure your crankcase breather is not blocked in any way.

[Shrew]

Originally Posted by Idle

I
Will an oil stop solution help?

I would only consider something like that as a "Get Home" emergency work-around. I would not consider that a solution, nor would I consider it if I was in port with a mechanic and parts available.

For now, I'd check the fluid before and after running the engine, topping off as needed. I'd also keep a mental note of the volume of oil leaking over time, with an eye to recognizing whether the leak is increasing.

[Scubaseas]

For a leaking rear main or crankshaft seal usually the closer to "full" you are the more the seal will leak. If nearer 1/2 or 1/4 from "add" it will usually leak about 50% less. Depends on the engine but generally true from my experience. As long as you have oil in the engine , keep the bilges clean and not discharge the oil overboard it's up to you what you do about it or how you treat it. I'm sure you'll get advice ranging from only hire lab coated professionals to throw some sawdust in it (don't do this). You can buy a lot of oil and engine diapers for what a boat yard will ding you to change the rear crankshaft seal. Your boat. Do as you wish. Me? I'd change it but I might buy myself some time by putting the goo into the engine. But then I do all my own work and I work cheap for myself.

[Ballsnall]

Originally Posted by Idle

I have a Volvo MD 2040 engine at around 3000 hrs. There is oil leakage for some time. The amount is not serious but annoying. The mechanic has seen the leak from crank posterior seal.
Will an oil stop solution help?

No, not on an oil seal, they may help with leaky gaskets.

Can it cause any harm to other parts of the engine?

Generally safe, I haven't heard of any direct damage other than the through internal cleaning required on rebuild.

A crank seal is an easy fix, just replace the seal.

[skipperpete]

That 2040 rear shaft seal is not your average lipseal and is about 5” in diameter. To replace it requires the removal of not only the gearbox and flywheel but also the flywheel housing which often proves quite difficult to separate from the engine block due to the sealant required for that joint ........so if it’s a minor leak just do the absorption pads but if it gets worse, be prepared for a slightly more complex than usual seal install. Oh , the seal is about $30 from Parts4engines but I suspect way more from Volvo. [ATTACH]

[Madehn]

Agree with will help with gaskets but not with seal. I would put it off if only leaking slightly. Sounds like this one is a PITA to do. How hard is it to pull the whole engine. From the sound of the job if possible I would pull the whole thing and do a quick self rebuild while at it if I HAD to do it. Best of luck.

[Idle]

Thank for all the responses. The leak is not quite an amount in my motoring hours. What I collect from your advices is “ It is unlikely that additives will help. No need to be fastidious, leave it to time and get the seal changed when needed. “ By the way the breather is not clogged due to my mechanic.

[SailingHarmonie]

The way these "stop-leak" products work is they contain a solvent that intentionally attacks and swells rubber parts. The hope is that they then make better contact with things and the leak stops--like magic.

The issue is even if they work, they work by softening and swelling the rubber parts. This of course leads to dramatically shorter life for ALL the rubber parts, not just the one that is leaking. Consider it a temporary fix at the very best, and a DFI at the worst.