Crusader 350 / 270 hp Temperature

[LeapofFaith]

Hi Folks,

What is the operating temperature range for a 350 Crusader / 270 hp with fresh water cooling? This is a new boat to me so I am not sure what is normal and what is not. I did a quick search under "temperature" but did not see the question previously asked.

Thanks for letting me tap into the wealth of knowledge here.

[mjk1040]

Our 1988 Mariner with 350 Crusaders and new fresh water impellers would get up to 130 max and then drop down to 100 after the thermostats opened. Of course this can vary a little depending on the water temp you are in. These were repowered long blocks.
Mike

[Viper]

Fresh water systems (coolant in block) are typically 160 deg but may have also been fitted with 140 deg stats.

mjk1040, if she is actually dropping down to 100 deg, that is too cold IMO. Your engine isn't running efficiently at that temp. You may want to confirm that with a temp gun in case it's a sender or gage issue. Won't be exact reading on the outside of the sender but should give you a close idea of what she's really at. If she actually is at 100 deg, your t-stat may be sticking open.

[mjk1040]

Viper, IYO, you are correct, these were an open system, no coolant in the block, straight cooling from the lake water, never saw any temps above 130 all the time I owned her. The 1998 355MY/AC we have now has the same open system with 454's and they too run around 130 if my memory serves me right. A closed system should run warmer IMO, and neither boat had or has sea strainers on the engine water supply's, go figure?

[Viper]

Raw water applications (no coolant) are typically outfitted with 140 deg t-stats. But, in raw fresh water applications (lake-no coolant) you could use a 160 deg stat to run the engine at a better temp. The key is to not run at 160 deg in a salt raw water application. Again, not that your engine won't run right at a lower temp, it will just be more efficient if you get the temp up higher.

[mjk1040]

Your right on the money Viper, just checked a couple part catalogs on the crusaders and they all called for a 143 degree thermostat. And with electronic gauges we all know they aren't 100% accurate and could very well have a 10 degree +/- variance and a temp gun will give you a much better idea at what temp really is.

[LeapofFaith]

Thanks all for the info Much appreciated

[Redemption]

Thanks and appreciate that information.

Source of the post Your right on the money Viper, just checked a couple part catalogs on the crusaders and they all called for a 143 degree thermostat. And with electronic gauges we all know they aren't 100% accurate and could very well have a 10 degree +/- variance and a temp gun will give you a much better idea at what temp really is.