Sealants:

[cannuck]

I bought an M-F 1440V (Iseki) with E3CD-T engine that had been run without coolant. Minor bore damage, one scuffed piston, all rings fully annealed. Wanted to be sure the coolant passages were clean when hot tanking head and block, so pulled all of the 3/8 pipe plugs out of the head. They had a heavy, black sealant in the threads that obviously did very well sealing the cooling passages. I can not find sealant recommendation in manual, and dealer has no clue - plus of course anything from M-F once they have your money, you are on your own. So: need to find what sealant and/or what sealant chemistry is on those plugs. Also, what is used on no gasket surfaces by Iseki.

 

[dfkrug]

For coolant pipe plugs, I would use a pipe dope rated for 250F or better. I like RTV silicone, even tho it is not a thread lube.

Head gaskets, nothing. Other paper gaskets, either nothing or any automotive gasket sealer. In some cases (no clearance issues), replacing a paper gasket with silicone may be better. You can even use the extra-hi temp silicone in place of exhaust manifold gasket.

 

[ruffdog]

I would never use silicone for coolant passages. A good thread sealer that does work for coolant and oil is permatex aviation sealer. It is thin, comes with a brush, is good to 400 deg, and is great on threads. It is a black sealer and may have been used on your engine. Back in the day, we would use that sealer on head bolts that went into coolant passages (dealer truck mech). Also, the coolant drain pipe plug on the side of the block.

https://www.jamestowndistributors.com/product/product-detail/9403

 

[dfkrug]

I would never use silicone for coolant passages.

Why not?

The nicest coolant hoses I have ever bought and installed were blue silicone. Same for soft air hoses on turbochargers.

 

[Topzide]

On older engines with paper gaskets, I like to use a coating of shellac. Sometimes can be used on its own, if the clearances are tight enough. I would second aviation sealers! www.Skygeek.com has some good stuff. They do have a nice fuel tank sealer.

 

[etpm]

Loctite 554 and 5770 are two good choices. I have had extremely good luck with Loctite products over the years. They have performed better than any other thread sealant or thread locker product. I am a retired machinist and used Loctite stuff regularly. Never had a comeback, the stuff never failed to keep parts assembled or sealed. I have no connection with Loctite or Henkel except that I buy their stuff.
Eric

 

[ruffdog]

Why not?

The nicest coolant hoses I have ever bought and installed were blue silicone. Same for soft air hoses on turbochargers.

Years ago while working at a dealer, there were plenty of warranty claims of coolant leaks of covers using RTV by the manufactures. It just didn't work with coolant.

 

[cannuck]

discussed this with Henkel support and they recommended 567 - and I have a fair bit of this on hand so went with it. I believe similar chemistry to 5770 but something like 400F max temp.

 

[cannuck]

I am also going to use gasket dressing at least on head gasket. Once thing is together, I want it to stay that way. Worth noting: SOP at Rolls Royce was at least at one time to use dressing on head gasket, and IIRC it was the EU/UK version of Hi Tack from Permatex. Problem is: there are 3 grades and from what I was reading 80697 copper was the best choice. Put a call into PTex and they said in no uncertain terms THAT was the only one to use on head gaskets.