Closed cooling system

[bsh21wash]

I'm trying to understand this system a little more...are you not supposed to drain it for winterization since it does have coolant in it? if you have a closed cooling system what are you supposed to drain?

On mine I drained the block, manifolds, power steering cooler, all the big hoses that were going to the the heat exchanger. When I drained everything I was getting alot of green coolant. Are you just supposed to leave that in and just drain the block?

 

[HT32BSX115]

Re: Closed cooling system

Howdy,

Uh, No. you don't drain the coolant unless it's been in there for a good long time...couple of years etc...like a car.

The raw water side should be drained. You have raw water that goes from the drive to the oil cooler and power steering heat exchanger then it goes into the main heat exchanger. Then it's pumped back up into the risers/elbows on a "full system" on the way out (and the manifolds too on a 1/2 system)

So depending on what you have, you may still be draining the manifolds.

If raw water pooled in any of those components, it could crack something. I usually put 50/50 mix in a large wash tub and run the engine on an adapter and suck the 50/50 mix up into the system and let it drain back into the tub to flush the "raw" side of the cooling system with anti-freeze. It sort of lubes the raw pump too.

This way you eliminate all the pooled raw water in the heat exchanger, oil cooler, power steering cooler risers (full sys) (+ manifolds 1/2 sys) etc.

You do not have to drain the block and heat exchanger. That's the whole point of a closed system...


Regards,

 

[bsh21wash]

Re: Closed cooling system

ok im just a idiot, so how do you tell if you have a closed cooling system or not?

 

[erikgreen]

Re: Closed cooling system

Only closed cooling systems have heat exchangers

 

[bsh21wash]

Re: Closed cooling system

Im just trying to understand why my manual said to drain everything, if I do in fact have this closed cooling system?

How do you tell if I have a 1/2 system or full system? In the future should I just run this 50/50 mixture through the system? Will I not have to drain the block and manifolds?

Should I have any problems, since I did drain everything? Sorry for all the questions...this is brand new motor and I dont want to screw it up

 

[HT32BSX115]

Re: Closed cooling system

Well you don't have to drain everything if it's a closed system.

You need to do a little inspecting. The coolant will go thru everything EXCEPT the risers on a closed full system.

The elbows usually ALWAYS have raw water going thru them.

There'll be a separate hose connection to the risers for raw water to go thru them.

In a half system, The discharge (raw) water will come out of the heat exchanger and go into the exhaust manifolds. there is usually no separate connection for the risers/extensions. raw water is pumped into each exhaust manifold at the bottom and exits out thru the risers along with the exhaust.

In a full system. The coolant is pumped into the bottom of the exhaust manifolds and exits out thru a fitting at the top of the manifold (or top of the riser extension) The coolant is blocked from entering the elbow by using a plate or block-off gasket.

If you go to Boatfix.com they have been very gracious to post online, manuals that you can peruse that have diagrams of raw water systems.

http://www.boatfix.com/merc/Techbk/97/97hga6.pdf

Here's some more examples.

These people explain them pretty good. -->


This is a "half" system

This is a "Full" system