Another Stupid Question

[Tregaskis]

Can anyone tell me on a Chevy V-6 (OMC)..does the coolant circulating thru the engine circulate upwards out of the thermostat housing or downwards into the thermostat housing? We are installing new manifolds on a closed system and I am not sure which way to hook up the coolant lines to the manifolds. I know to hook the feed line on the low side and the exit line on the high side of the manifold but not sure whether the feed line comes from the thermostat housing or from the heat exchanger.
Thanks

 

[Don S]

Re: Another Stupid Question

A lot depends on year and type cooling system you have. Kind of sounds like you are trying to build your own system with just a heat exchanger of unknown type.
You can NOT use a raw water system thermostat housing on a closed system. ONLY the coolant return from the engine to the heat exchanger is used in the closed system. The raw water type distributed the water to different sections.
All your raw water cooling hoses to the manifolds and risers will come from the raw water side of the heat exchanger.

 

[Bondo]

Re: Another Stupid Question

does the coolant circulating thru the engine circulate upwards out of the thermostat housing or downwards into the thermostat housing?

Ayuh,......
On All Chevies used in Boats,.....
The water is pushed Into the block by the recirculating pump, thru the block, up thru the heads,+ Out the T-Stat........
But,......
As Don says,.....
Your question is much too Vague to answer Correctly.......

 

[Tregaskis]

Re: Another Stupid Question

Thanks. I am sorry if I was not any clearer than mud but you did answer my question. What we are trying to do is replace the old rotten manifolds on a 3.8L V-6 OMC (closed system) The old style manifolds are not available so we have had to go to the newer 4.3L center riser manifolds as replacements. The original end riser manifolds had a 1" hose from the thermostat to the back upswing just below the riser and a 1" hose between the front of the manifold and the heat exchanger. The new manifold says to run the coolant hoses feeding from the low point to the high point on the manifold. I wanted to make sure I was connecting the hoses correctly. I hope that explains what we are doing better. Again, Thanks and Merry Xmas.

 

[Don S]

Re: Another Stupid Question

Are the manifolds going to be cooled with antifreeze or raw water? That is going to make a huge difference in how it's plumbed in.

 

[whywhyzed]

Re: Another Stupid Question

The new manifold says to run the coolant hoses feeding from the low point to the high point on the manifold.

I suspect that is to prevent the manifolds from gravity draining - makes them have to continually "overflow".
The connections on the old 3.8 manifolds probably went out the riser and out to the lake, but you would need to look at the old 3.8 riser gasket to see if that was the case.