178 degrees seems hot?

[chomamma]

New to us, but only has 5 hours on engine. Replaced the impeller but still runs about 178 degrees after it warms up. Runs good and no bells. But everyone I see here says 160 is normal. I havent pulled Tstat but will. Also I'll check with infared gun this weekend.

2000 Bayliner with 3.0l

 

[bobhol]

Re: 178 degrees seems hot?

I am going thru the same situation.I run a tad over 180 but I checked the engine with an IR heat gun and it is 167 or so and cooler at different locations ...my gauge or sender must be out .I changed impeller and thermostat as well ,thinking they may be the cause.My thermo did make a difference as I was touching 200 on the old one which was original...check your temp with an IR gun...regards,Bob

 

[bigdan1]

Re: 178 degrees seems hot?

still , 178 is not hot !

 

[Lou C]

Re: 178 degrees seems hot?

I know that for my OMC with the 160 stat the testing procedures for the stat say that is starts to open at about 160 and should be fully open at 182 (the ones I have tested have fully opened at more like 165-170 though). So 178 might not be too hot but the upper end of normal. Interesting to note that most boat manufacturers tell you the opening temp of the thermostat but not the actual normal operating temp range which is a lot more important!
Mine typically runs between 160-175 so depending on how accurate your gauge is it could be fine...

 

[BAproject]

Re: 178 degrees seems hot?

178 is only too hot if you are running in salt water...then you need to stay below 165 or salt will crystallize inside the engine cooling channels

 

[EddiePetty]

Re: 178 degrees seems hot?

178 is only too hot if you are running in salt water...then you need to stay below 165 or salt will crystallize inside the engine cooling channels

....on sea water (open) cooling systems.

 

[BAproject]

Re: 178 degrees seems hot?

178 is hot then

 

[ryanr623]

Re: 178 degrees seems hot?

178 is hot then

Not at all. 200 and above is where you really need to start worrying.

 

[Bondo]

Re: 178 degrees seems hot?

Ayuh,.... Water boils at 212?.... Turns to Steam,... Steam don't cool...

210? is Hot....

178? could just be gauge differential... I wouldn't be tearin' it apart just yet...
I'd be lookin' at water Flows 1st,... Pull the mainline coming in to see if it's pumpin' real Good...

 

[bruceb58]

Re: 178 degrees seems hot?

Get an IR gun and find out what it really is. Don't trust the gauge.

 

[bigdan1]

Re: 178 degrees seems hot?

yes water boils at 212 F but the gauge reading ,is at water exit not water entry (in the engine)

personnaly id rather run at 175 then 165 ....

 

[erikgreen]

Re: 178 degrees seems hot?

Check your thermostat. Maybe someone put an automotive thermostat into the boat engine, which would make it run hotter than it should.

Boat t-stat should start to open just over 110 or so and fully open about 142 degrees.

Edit: The only place an IR thermometer should read 175-200 is near the carb on top of the intake manifold. Hot spots in the exhaust manifolds might be 175 or so, but that indicates a manifold spot with no water flow (bad) which probably should be replaced.

Erik

 

[Lou C]

Re: 178 degrees seems hot?

Some older Mercs came with a 142 stat, but most newer Mercs and pretty much all Volvos and OMCs had a 160 stat, so you have to know what your engine is supposed to have in the first place. If it's running within about 15 degrees higher than the opening temp of the stat I'd say that's OK.

 

[BAproject]

Re: 178 degrees seems hot?

You're running in salt water....salt crystallizes around 175 degrees, 178 is too hot, you should be around 150-160 with a 140 t-stat....Its that simple...and yes check with IR temp gun to verify temps, these gauges tend to be off the older they get.

BAproject