km1125 wrote:Source of the post You really shouldn't lose any antifreeze at all discoing the water heater. You'll lose a few cupfuls when you remove the hose but you should be able to get the other hose (the loop) on pretty quick and stop the loss. Then, you could blow air into one of the hoses going to the water heater heat exchanger and recover all that coolant out the other side. Use that to top off whatever you lost in the engine.
But, that said, getting back to your original question... 'how would you do it'? We'd have to know the exact model and year of your engines to find out. Then it would just be looking at some parts lists to figure it out.
IIRC, you have some 454 Crusaders. Below are some water flow diagrams for both the freshwater flow and raw water flow and you can see the differences. There's a different thermostat housing so that the raw water goes there first, then down to the water pump, rather than to the heat exchanger. There's also a blockoff plate (not shown) between the manifolds and the risers on the freshwater cooled so that the antifreeze in the manifolds doesn't get to the risers. In the raw water version, that blockoff plate is replaced with a gasket, with the hole in the gasket towards the top.
You'd need to plug off the holes for hoses on the risers and the ones at the back of the manifolds (I actually have the plugs for this if you need/want them.. they are really large)
You should also change the thermostats, because the raw water versions used a 143F, whereas the freshwater used a higher one (160F, 170F or 180F). 210F is WAY TOO high and should never get that high unless there's a problem and a little leak wouldn't be that problem unless it was running out of water.
Thanks KM
km1125 wrote:Source of the post Thought of a better way to bypass the water heater without losing virtually ANY coolant.
First, open the cap from coolant system on the engine to relieve any pressure in the system. Then put it back in place.
A foot or two from the engine, use two clamps (like wood clamps) on each hose to pinch them shut about an inch apart. Cut the hoses between the clamps. Raise the two coming from the engine above the highest point on the engine or heat exchanger and remove the clamps. Use a bronze barbed fitting to connect these two hoses and clamp tight. No loss of coolant (Ok, maybe a FEW drops). Put one of the ends of the hoses coming from the water heater into a bucket and remove its clamp. Raise the other hose coming from the water heater and remove its clamp and blow air into this hose. The remaining coolant in the hot water heat exchanger should be blown out into the bucket. Save that coolant for later use.
A leak could absolutely cause a high temp situation. The closed coolant side runs off of pressure. If the system isn’t making 19lbs (or whatever the radiator cap is rated for), the t-stat won’t open properly, and it will run hot.
The reservoir is the highest point of the system, followed by the heat exchanger. I’m guessing that once I open the HW loop, it’s going to shoot out of there like a rocket.
Do you happen to know what size hose it is, that goes to the HW system. Seems like it’s about a 3/4” ID, but there’s going to be no good way to measure it while it’s shooting out everywhere.
These engines have a horrible design for draining the coolant out of them.