Volvo thermostat and saltwater operation

[dannyual767]

I'm just asking this question for the sake of discussion since I won't be able to water test my boat for about 2 more weeks.

I've got a 2004 Stingray 200LX with the 220hp carbed Volvo 5.0GL-D engine. I dewinterized it recently and it runs great on the garden hose. However, the temp doesn't want to stabilize. It wants to keep rising to 180? and even as high as 190? before I shut off the engine. Garden hose is hooked up to the engine compartment flush port (no muffs) and the hose is on full blast.

I've got he downloaded repair manuals for this engine and I know that the thermostat housing outlet hoses to the exhaust manifolds should be hot when the (150? rated) thermostat is open. These hoses are not hot! It appears that the thermostat isn't opening when it is mounted in the thermostat housing. I've already taken it out and checked it in a pot of heating water on the kitchen stove with a thermometer. It works as it should in the pot.

This thermostat was brand new at the beginning of last season (2010.) It ran perfect all last summer. I'm a saltwater boater so I'm just wondering if I need to be using a brand new thermostat each season ?

 

[Don S]

Re: Volvo thermostat and saltwater operation

Thermostats used in salt water can hang at times. Was it an OEM stat, or aftermarket?
Since you boat in salt water with a raw water cooled engine, have you considered installing a Neutra-Salt system?
http://www.volvopentastore.com/QL-N...*****.040700135--store_id.366--view_id.352393

 

[dannyual767]

Re: Volvo thermostat and saltwater operation

Don, it is an OEM stat. I kept the packaging and I just checked to be sure.

Anyway, the thermostat checked out fine in a pot of heating water on the stove but it just doesn't seem to be opening when it's actually on the engine.

I think that the Neutra-Salt system is something that I need to go ahead and purchase. With plain, fresh water, it's really tough, if not impossible, to get rid of all the salt!

 

[Justin Kennedy]

Re: Volvo thermostat and saltwater operation

As your manifolds and risers get rusted out, it will restrict water flow and cause higher temps. Mine went from around 200 to 150 after replacement of manifolds and risers

 

[JoLin]

Re: Volvo thermostat and saltwater operation

As your manifolds and risers get rusted out, it will restrict water flow and cause higher temps. Mine went from around 200 to 150 after replacement of manifolds and risers

I'm gonna agree with this. A 7-year-old motor used in salt is due for new manifolds and risers. Neutra salt won't reverse the corrosion if they're already plugging up. And, you can't tell if they're good via a visual inspection. You need to replace them on a schedule and according to my mechanic, yours are about due.

My .02

 

[dannyual767]

Re: Volvo thermostat and saltwater operation

I bought the boat in early April 2009. Prior to that, it was a freshwater boat from Ocala, Florida. In other words, the manifolds only have 2 summers of saltwater use...............to the best of my knowledge!


posted by Justin

As your manifolds and risers get rusted out, it will restrict water flow and cause higher temps. Mine went from around 200 to 150 after replacement of manifolds and risers

I seem to have a real good flow of outlet water at the outdrive. Wouldn't restricted exhaust manifolds hinder the flow of outlet water?