I used ATF to soak the pistons and rings with a head removed as I can't get MM here - it did quite a good job of cleaning everything up.

Unfortunately (for my wallet at least) I had to go deeper and strip the bottom part of the engine too for machining so I never got to run the engine with ATF on any of the surfaces.

I'm interested to hear why MM is OK and ATF isn't - I've never even seen MM - is it of a similar viscosity?

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!