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4.3 GXI-G Cooling Problems (and a small starting problem)

J

johnt

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Good afternoon! Looking for tips/advice on my 2007 VP 4.3L GXI-G in a Four Winns Horizon.

Last fall I blew the big hose from the thermostat housing to the engine water circulation pump. Didn't think anything of it, replaced, and back on my way. This spring I blow the 1" hose from the impeller housing up to the thermostat housing but I had noticed that the temperature was fluctuating a lot rather than holding a steady temp. So I replaced that hose, the thermostat, o-ring, gasket as well as the impellor. I found a couple vanes broken off of the impellor, one of which I couldn't find. So I get back on the water feeling really good that all is new and 4-5 hours of run time later, I blow the same 1" hose again from the impellor housing up to the thermostat housing!! WTH??!!

So I realize that this hose is carrying lake water up to the thermostat, right? This leads me to believe it isn't heat that is blowing this hose, but pressure? Seems so odd. So I have another hose to put on it, but am wondering what any thoughts could be? Could that missing impellor vane be sitting somewhere and causing trouble? Where could I look for it? Maybe the first hose I bought was bad and had a weak spot, is that a thing? Seems unlikely I guess.

I appreciate ANY thoughts on this as it's driving me crazy and the boat is somewhat unreliable right now.

Also, when going to start the engine, turn the key and it takes a second before the starter engages. It's a new battery and still has a small delay before it actually turns over. Is the starter solenoid a unit with the starter or could it be in a remote location away from the starter? I haven't looked yet.

Thanks!! John
 
johnt said:
Good afternoon! Looking for tips/advice on my 2007 VP 4.3L GXI-G in a Four Winns Horizon.

Last fall I blew the big hose from the thermostat housing to the engine water circulation pump. Didn't think anything of it, replaced, and back on my way. This spring I blow the 1" hose from the impeller housing up to the thermostat housing but I had noticed that the temperature was fluctuating a lot rather than holding a steady temp. So I replaced that hose, the thermostat, o-ring, gasket as well as the impellor. I found a couple vanes broken off of the impellor, one of which I couldn't find. So I get back on the water feeling really good that all is new and 4-5 hours of run time later, I blow the same 1" hose again from the impellor housing up to the thermostat housing!! WTH??!!

So I realize that this hose is carrying lake water up to the thermostat, right? This leads me to believe it isn't heat that is blowing this hose, but pressure? Seems so odd. So I have another hose to put on it, but am wondering what any thoughts could be? Could that missing impellor vane be sitting somewhere and causing trouble? Where could I look for it? Maybe the first hose I bought was bad and had a weak spot, is that a thing? Seems unlikely I guess.

I appreciate ANY thoughts on this as it's driving me crazy and the boat is somewhat unreliable right now.

Also, when going to start the engine, turn the key and it takes a second before the starter engages. It's a new battery and still has a small delay before it actually turns over. Is the starter solenoid a unit with the starter or could it be in a remote location away from the starter? I haven't looked yet.

Thanks!! John
Click to expand...

I think on the blowing hoses you have a restriction either from corrosion or the pieces of the impller that went AWOL. I owuld follow the cooling water paths to the exhuast maifolds and take off the risers/elbows and check those passages which are only 1/4" wide or so... I bet you will find the outlet into the where water dumps into the exhaust is clogged somewhere.

On the starter- I dont know if you have a remote slave relay like on mercruiser but probably I would check the connections on the starter circut , battery cables at block (ground) and starter connections etc makes sure they are shinny metal and tight clean with sand paper as needed. Willing to bet you have corrosion or a loose connection
 
you are going to have to remove the thermostat housing and check that all the passages are open, including the small bypass passage, and may also need to remove (drain water first) the exhaust elbows to check for rust clogging cooling passages.
if an impeller shreds on a volvo the pieces will probably clog the thermostat housing...
 
Just wanted to say THANK YOU to this group! I took a close look up in the thermostat housing and sure enough I found my bits of impeller. Got that all cleaned out and I think it is going to be fine now. I also found my positive battery cable at the starter to have just a tiny amount of play in that brass block connection. I got that all tightened up and it seems better too. Thanks so much for pointing me in the right direction!

John
 
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