In my last step to upgrading to my 650 engine, I quickly installed a 3.5 liter aluminum sump / oil pan (pictured below) to replace the 2.5 liter stamped steel one that came with the engine. It has a 10mm female hex head (allen key) plug flush on the bottom. In my haste to install it, I didn't even take the plug out and look at it first. I just slapped it on with new bolts and Permatex Ultra Grey RTV.


Now, after sitting a few days with oil refilled, I noticed it is leaking drops (8 cm puddle under the pan). It's definitely coming from the drain plug and not the top flange or the RTV seal. I gave it an extra 2 mm turn to snug it up the other day, but it's bottomed out now and still leaking.



Does anyone know the best way to stop it from leaking? I thought I read that a Locktite product might work, but I don't want to make it harder to get the plug out for future oil changes. I am not sure what other thread sealer is acceptable for a situation where it will be pretty hot. Is it supposed to have a crush washer on it? Because I stupidly put it on without inspecting it first, I don't know if there is a washer on it now. I'm not able to get to it for a few days, but if there's any odd size washer or gasket, I'll probably have to order it and would like to get that done so I have it when I'm ready to fix it.



Thoughts appreciated!

Uaglio said:

Does anyone know the best way to stop it from leaking? I thought I read that a Locktite product might work, but I don't want to make it harder to get the plug out for future oil changes. I am not sure what other thread sealer is acceptable for a situation where it will be pretty hot. Is it supposed to have a crush washer on it? Because I stupidly put it on without inspecting it first, I don't know if there is a washer on it now. I'm not able to get to it for a few days, but if there's any odd size washer or gasket, I'll probably have to order it and would like to get that done so I have it when I'm ready to fix it. Thoughts appreciated!

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Hi Uaglio, it's a bummer but you will have to drain the sump (into a clean pan and then refill) take out your drain plug clean it with white spirit and either use a suitable fibre washer or try Plumbers PTFE thread seal tape, it comes in different sizes and is cheap to obtain. For the best job use both

Ian.

It should have a copper washer under it. Mine leaked so I put some PTFE tape on the threads but I still get the odd drop. Think I’ll go for a dowty washer next

thank you gents. I'm going to try both a crush washer and thread sealant goop. I see a few manufacturers make stuff specific for oil plugs.



By any chance, would anyone know the inner diameter and outer diameter size of the plug washer?

Had the same problem so i drain it and use some red rtv but the problem is that the surface that the crash washer sits is untreated and not dead flat. I removed it and mill it down so now I am only using the crash washer and seals perfect. They had to machine it in the factory before release it for sale. I also opened the side hole and install a temp sensor.
Thomas

Just a quick follow up. Used a 22mm fiber washer and Permatex thread sealant for oil-exposed applications, and all dry now. Problem fixed.

Uaglio said:

thank you gents. I'm going to try both a crush washer and thread sealant goop. I see a few manufacturers make stuff specific for oil plugs.

By any chance, would anyone know the inner diameter and outer diameter size of the plug washer?

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As others have recommended, use plumbers tape. I did it on the oil pan and the gearbox and it's almost completely stopped it from the oil pan.