Thermostat housing mount torques

[clunker]

This question was in an old thread, but I think unanswered (https://www.sl113.org/forums/index.php?topic=6110.0)

What is the correct torque for the two nuts that go on the two studs (located in the cylinder head) to mount the thermostat housing body? (Note: not the four thermostat cover bolts)

These are steel studs that through a cast aluminum housing, so want to get it right. I snugged them up when I re-installed the housing, but immediately have a coolant leak down one of those studs - but I am cautious to just crank it in!

[Benz Dr.]

Take it back apart and clean the studs well before you mount the housing. I would also strongly advise that you coat the studs with anti seize so that it prevents any corrosion between the studs and the holes in the housing. Leaving it full of coolant would be a complete disaster in the future.

It should also be noted that the nuts that hold the housing on tightly are 12 x 8 mm and not the standard 13 x 8 mm that you would normally find on almost every other application on your car. These smaller sized nuts are required for clearance between the nut and the surrounding casting. 13 mm won't work properly.   

[clunker]

Thanks Dan.

I had put on plenty anti-seize, but will be sure to do again when I reinstall - I have disassembled it all again anyway. Replacement M8 12mm hex nuts are a bit of a pain to find but have some to hand now, so all set.

I had previously failed to notice that a PO had installed that one thermostat housing stud the wrong way round, so was never going to sit right (I think liberal liquid gasket used by PO).

Still not found a number for the torque for those thermostat housing nuts (neither on forum, BBB, nor Haynes) but will go with, say, 15 lb-ft and see if that feels snug (and leak free).

[Benz Dr.]

Just snug them down until they feel tight. Coolant pressure is not very high on our cars - maybe 7 - 9 PSI so nothing should leak if everything is assembled properly.