Coolant change Merc closed system
 

2002 496 closed system. Other than drain refill with 50/50 distilled water does system need to be bleed out and if so how?

thx

Brass Air bleed mounted on top of thermostat housing.

I don't remember bleeding mine. The coolant tank is the highest point on the system. Just take a gallon or two of pink with you on your first run, and top off if the reservoir goes a bit low.

https://www.offshoreonly.com/forums/...nt-change.html

I posted the proper procedure from the 496 FSM in this thread.

My closed coolant system (the one from CP performance) specifically called for green. Actually, I'm not sure it was in the literature, but I believe I called them and asked.

When I filled mine it was mounted to the front of the heads high enough that it took almost no antifreeze to top off, but there wasn't anything on bleeding it.

use dex cool then mix 50 to 50 with DISTILLED WATER. the slower you poor in the coolant the less air in the system. - leave cap off for an hour or 2 - go eat comeback check level. Add more if needed.

John - should I not be using the green stuff? Did I get that wrong?

Merlin blocks 565, aluminum heads, CP performance half/system.....

The OP and some others have factory engines filled with Dexcool from Merc.

I wouldn't use dex cool if you have the choice. GM had a lot of gasket issues with it, and if it runs low it reacts with air and causes an acid sludge. I'd use the green stuff, doesn't "last" as long but nobody has issues with it.

MERC 496 is DEX cool PINK stuff

other can post their engines for that info - an example - all volvo pentas us the same coolant as their diesel side - Yellow coolant.

I would not mix coolants with other style of coolants