8.2 closed cooling questions

[Tenn Formula]

Hello everyone, i'm new to the forum and hope to be able to pick up some good info here. i'm looking for some help with my '95 8.2l Bluewater inboard exhaust. the boat is currently used in fresh water but has seen some extensive cruising in the big pond as well. i haven't owned the boat that long and would like to do some extensive maintenance on the exhaust. my questions are: Bluewater means the manifolds are in the closed cooling loop? if so, is there a need to replace the manifolds when the risers and spacers are replaced since they are not exposed to raw water? i think the heat exchangers should be removed and checked/cleaned too. can anyone give me an opinion on that as well? i am planning to do the raw water side first and then changing the thermostat and antifreeze on the closed side afterwards. does anyone see a problem with this or have any suggestions? Thanks

 

[Don S]

Re: 8.2 closed cooling questions

'95 8.2l Bluewater inboard exhaust

I have no idea what you are asking, is this a 1995 Bluewater boat with an 8.2L inboard engine and you have a question about the type exhaust you have ?????

If so, what engine, Volvo, Mercruiser? Is it a true inboard or an IO with an outdrive?

 

[Tenn Formula]

Re: 8.2 closed cooling questions

1995 8.2L Mercruiser Bluewater Inboard w/Hurth v-drives. my questions were about preventive maintenance and wether or not the exhaust manifolds are in the closed cooling loop. Does the "Bluewater" designation for the engine mean that the exhaust manifolds are closed cooled?

 

[Don S]

Re: 8.2 closed cooling questions

I don't know if Bluewater means the manifolds are fresh water cooled or not. Does the cooling water hoses going to the bottom of the exhaust manifolds go to the thermostat housing?

 

[Tenn Formula]

Re: 8.2 closed cooling questions

i'm not sure but i can check. what would that tell me?

 

[Don S]

Re: 8.2 closed cooling questions

That would tell you that antifreeze is going into the manifolds. The thermostat housing only has antifreeze in it, no sea water.
Another easy way of checking is to loosen the hose on the bottom of the manifold and see what comes out. If antifreeze, then it's in the closed cooling system ...... UNLESS, you winterized the engine and used antifreeze in the raw water side.

 

[Tenn Formula]

Re: 8.2 closed cooling questions

ok that sounds like a good easy way to check. IF they have antifreeze in them should they still be replaced as a preventative maintenance item? as far as i know they have never been replaced. i plan on doing the risers and spacers anyway so i'd like to address the manifolds at the same time. i just don't know what is recommended on closed cooled manifolds.

 

[Don S]

Re: 8.2 closed cooling questions

If they are antifreeze cooled, they (the manifolds) probably won't be bad, just inspect the gasket surface if you see any indication of leakage between the manifold and riser.
The risers are the first thing to go with a full cooling system, if they are over 5 or 6 years old, it sure wouldn't hurt to pull the risers off, inspect (especially the gasket surface) and either reinstall or replace them. Use the OEM gaskets and instructions for installation.