Thermostat Housing

[Viper]

Haven't forgotten about you, just haven't gotten anywhere with Volvo yet. I see what you mean though about those not being available anymore. Trying to get more info that might help with other sources. Will let you know if I find anything further.

PS; at the very least, we know that it's just a GM 454

[MyPleasure]

Thank you so much Viper! It’s so hard to find information about Volvo marinized engines, without trying to find information about specific parts, which are mostly discontinued items!

[MyPleasure]

Would someone be able to tell me the purpose of the hose that goes from the top of the water pump, to under the thermostat housing is? I was wondering if I could use that to plumb into the bottom of my exhaust manifolds for fresh water cooling the manifolds. Then I could run hoses from the top of the exhaust manifolds to the thermostat housing to complete the flow circuit.
Thanks for any help here fellas!

[km1125]

You should post a picture so we know exactly what you're referring to. Typically the hose that goes directly from the water pump to the base of the thermostat is a bypass hose, and is used for circulating water through the engine before the thermostat opens. This is also used (sometimes) as a heating loop for the potable water heater (in a boat) or the cabin heater (in a car, but could also be in a boat).

I don't think there'd be enough flow in that circuit to cool both manifolds, especially at cruise loads.

[MyPleasure]

Thanks KM1125, that makes perfect sense. There goes another idea down the drain. These Volvo’s are a pain to try and find the parts to put closed cooling on, especially when the one part that I need ( thermostat housing ) is no longer available!

[bud37]

I am actually amazed there are not old scrap engines out there with those parts you need on them.
It is important to do it right and not to short circuit the cooling system functionality as it is now....good idea.

[Viper]

Having a hard time in my area but try an OMC dealer. Does it say OMC anywhere on your engine?

[MyPleasure]

Not that I’ve found yet, Viper. We are on Vancouver Island on the west coast, and though there are a lot of boats here on the island, there is not nearly enough marine suppliers or boat or engine junkyards here. It can be pretty hard to find much for older boat supplies here.
I guess that for now, I’ll install a way to flush the salt water cooling systems out and make them last as long as possible.
Thank you for all the advice and help fellas!