Mercruiser 5.0 closed cooling conversion?

[backyardmechanic]

i have a 1994 mercruiser with alpha one outdrive. i am considering converting this to a closed cooling system but can i do this without adding a water take up pump? Market converstion kits do not include a pump and seloc manuals show there is one at time of factory install.

 

[Haut Medoc]

Re: Mercruiser 5.0 closed cooling conversion?

You do not need it, the pump in the drive is sufficient.....

 

[Don S]

Re: Mercruiser 5.0 closed cooling conversion?

It's recommended that you not convert to a closed cooling system after 125 hours or 1 years use. Especially if it was used in salt water. Corrosion has already started and rust will flake off and clog the passages in your new heat exchanger.

 

[dan t.]

Re: Mercruiser 5.0 closed cooling conversion?

I converted from a block only fwc system ,to a closed cooling system 4years ago. I removed the manifolds ,removed all the plugs,baked them in a barbicue on low heat for 1 hour,blew them out with air, this removed a lot of rust and scale.I then replaced the plugs,filled them up with muratic acid and let them stew for 1 hour.I rinced them out with water,lots of water,then blew them out with air again. I use only the water pump in the leg,this system has worked perfectly for 4 years and runs at 160 at low speed,180 under load

 

[DrCox]

Re: Mercruiser 5.0 closed cooling conversion?

What is the reason that someone would convert to a closed water cooling system? Advantages / disadvantage?


-DrCox

 

[mylesm260]

Re: Mercruiser 5.0 closed cooling conversion?

Protect your engine and manifolds (if you decide to include your manifolds in your closed system) against 2 things.

1: Corosion from fresh/salt water
2: Cracking from freezing in the winter time


It is my understanding that manifolds and risers have a fixed life spawn when raw cooled. But when fresh cooled (antifreeze) they will last forever (well the manifolds will, the risers are always subjected to raw water)