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Discussion Starter · #1 ·
What should my engine temp be? It currently never seems to get over 140 degrees. Someone said it should be around 200. Should I put a new thermostat in? It's a 89 454 mag.
 

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200 is too high! that's called boiling water: winker: 140 sounds right if you have a 140 t-stat :bigsmile: I run a 160 t-stat on my SBC and usually run around 170. but the 454's may run a cooler one...not sure
 

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Discussion Starter · #3 ·
This might be a stupid question but how are thermostats listed by the max allowable temp? If I am going to buy a new one do I just say I want a 170 or whatever it may be?
 

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I think stock merc carb motors have 135* t-stats and EFI/MPI motors have a 165*.

Either way 200 is too hot. Mine usually runs around 170*.
 

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well if you have your serial number off your motor you should be able to look it up, or go to a local marine store and they'll set you up with whatever came stock. as far as I know there are only 2 temps available like super listed above.
 

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Discussion Starter · #7 ·
So it sounds like there is no point in changing the thermostat based on running at 140 I guess. Would there be any advantage to running at 170?
 

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sounds like mine is out of whack then. 1994 454 runs at 175 all the time. Should I change the temp gauge that screws into the block? The gauges are brand new.
 

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Discussion Starter · #11 ·
Leud Conduct said:
sounds like mine is out of whack then. 1994 454 runs at 175 all the time. Should I change the temp gauge that screws into the block? The gauges are brand new.
Is the alarm going off?
 

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Discussion Starter · #12 ·
I just checked with a few auto techs here and they say that most car engines run at around 190 to 210 degrees. Why does a marine engine run so much lower at 140? Would it damage it if I put a 170 thermostat in it? I don't remember hearing my alarm go off when my water pump went and it was a lot hotter than 140. :confused: :confused:
 

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1. I system under pressure will not boil over as fast.

2. I would check your alarm sender to be sure it is working. My alarm sounds when my boat gets to 210*. Lived through this already. Carbed engines run hotter than fuel injected.
 

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When I pin my throttles the engines do not get even a little hot with 140*s. I had 175* thermostats the harder I ran the hotter it got. Just my personal experience.
 

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Unless your running an closed cooling system, you need to run at cooler temps to keep your oil temps cooler ...Remember that marine engines are always under load when your moving, and that creates internal heat, a cars engine is not always under load.
Cars as you know use closed cooling and use antifreeze under pressure through a radiator..
If your running 140 eish, thats not bad, unless your getting condensation in your engines oil.
 

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Discussion Starter · #16 ·
Hot'n'Bothered said:
When I pin my throttles the engines do not get even a little hot with 140*s. I had 175* thermostats the harder I ran the hotter it got. Just my personal experience.
Did it run better with 175's? Or did you even notice a difference?
 

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Bop said:
Did it run better with 175's? Or did you even notice a difference?
Weather and conditions constantly change and i don't pay real close attention except for what the plugs look like. I cruise 90% of the time on my boat so I am not trying to queeze every little MPH out of my boat. I don't race so it is what it is. I put the 175s in by accident and had problems until I figured that out which took a couple of weeks. :rolleyes:
 

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Hot'n'Bothered said:
When I pin my throttles the engines do not get even a little hot with 140*s. I had 175* thermostats the harder I ran the hotter it got. Just my personal experience.
Its funny. This is the reason I started to call the boat Hot and Bothered in the first place. :laugher: About 9 years ago. :eek: :winker:
 

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Discussion Starter · #20 ·
Hot'n'Bothered said:
Weather and conditions constantly change and i don't pay real close attention except for what the plugs look like. I cruise 90% of the time on my boat so I am not trying to queeze every little MPH out of my boat. I don't race so it is what it is. I put the 175s in by accident and had problems until I figured that out which took a couple of weeks. :rolleyes:
I'm the same, I can't remember the last time I pinned it WOT. I was just thinking it may run better at 175 than 140. What sort of problems did you have with the 175's?
 
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