cooling system problems 97 volvo 5.7 gli

[fisherman73]

I had my boat out at the coast this weekend and after a about a 10 mile ride I trolled for salmon for about 5 hours, my temp was at approx. 170 as it always is, but upon coming back in I noticed immediatly that the temp dropped to about 140 then slowly climed back up to 160. I was thinking t-stat but when I came back down off plane it climbed to 200 before I shut it down. I restarted and moved the boat a few times after that and was experiencing some unusual temps. It seemed that on plane I would run at 170 but when I came back down the temp would climb somewhat and then level out. What are your thoughts on this? This boat has been ran extensivly in salt water but has been maintained well and has nearly new manifolds and risers.

 

[Dunaruna]

Re: cooling system problems 97 volvo 5.7 gli

Raw water pump.<br /><br />Did you catch any salmon?

 

[Lou C]

Re: cooling system problems 97 volvo 5.7 gli

Raw water cooled? after a lot of salt water use the thermostats get sticky, I just changed mine (2 seasons use) because it was getting sticky, not letting the motor warm up until it was under load , and letting it get a little warmer than normal after coming off plane(160->175).<br />With a good stat and clean manifolds mine runs right 160 all the time.<br />I'd check both the impeller and the stat. In salt water they should be yearly maintenance items.

 

[fisherman73]

Re: cooling system problems 97 volvo 5.7 gli

Yes it is raw water cooled. I also was thinking raw water pump so I pulled and inspected it but all looked good. I also pulled the t-stat and it definatly was not new so Ill put a new one in and give it a whirl. Salmon fishing wasnt bad but all I could get was little guys I released 14 in two days.