Mercruiser 5 L mpi cooling system

[affa]

Hi,
I started the engine without the drive installed to heat up the oil before changing it, it come some water out in the exhaust and it was much white smoke, I thought the water would circulate inside engine when thermostat was closed? It has been winterised with antifreeze, my concern is if something’s gone wrong in the cold? It’s not closed cooling, and it’s the type where you can remove a blue plug in the bottom to drain the water from the engine
Regards
Affa

 

[Scott Danforth]

Since you did not have cooling water flowing to the motor when you ran it, you burned all the rubber bits in your exhaust

the white smoke is most likely steam and burning rubber

If you drained the block, heads, and exhaust manifolds prior to adding antifreeze, you should have been protected

 

[affa]

Ok thanks, the rubber in the exhaust, is that the flappers?

 

[Scott Danforth]

flappers and the rubber exhaust couplings. both rated to 250F max. however without water running, your exhaust goes from 200F to 950F

 

[affa]

Ok thanks, I’ll check them