2GM20F Cooling Fresh Water Pump replacement

[thetone]

My 1989 2GM20F cooling fresh water pump started making noise so I've decided to replace it. I am heading to the boat Friday with the new pump, a gasket, antifreeze, radiator flush, distilled water, a new belt and all new hoses. I've decided to use Prestone Comand Heavy Duty Antifreeze and Prestone Radiator Flush and Cleaner, I've heard bad things about Dexcool. I'm thinking about flushing the system and purging it of all the old green antifreeze before changing out the pump. Does anyone have step by step instructions on purging the system and getting all the air out? Also when installing the new gasket, what type of sealant should I use and should there be sealant on both sides of the gasket?

Any and all assistance would be greatly appreciated!

Thanks!

Thetone

 

[Deleted member 117556]

I recently did this myself, purged and replaced the coolant but not the pump. I googled the question and found a few videos plus instructions online for the 2GM 20F. I followed the instructions and the videos and had no problems at all. Might try searching these archives because I think there were some step by step instructions posted here by someone.
bob

 

[ggrizzard]

Permatex for the gasket?

 

[thetone]

I went down to change out the antifreeze and install the new water circulator pump. Turns out that there is no cock to drain the fluid from just below the hose on the port side of the engine. My engine just has a plug where the cock should be. I tried to get it out with the right size hex key but it wont budge. I drained the fluid by taking off the hose. Now I'm stuck with job of flushing and rinsing by removing the hose each time.

Any suggestions? Anyone?