4.3lx overheating

[Dillle209]

i have a 1997 Larson 174 sei with a 4.3lx alpha one never had problems with it over heating and yesterday it would fluxuate slowly between 175 and the red line on the photo but most the time dropped back to 175 i don’t know if it’s something i should be worried about .fresh water thermostat changed and impeller last season.i heard sometimes the gauges don’t read right to check with a thermometer?

 

[Lou C]

If you can pick up an IR temp reading gun you can take readings of the part of the intake manifold right below the thermostat housing, I have found that this follows the dash gauge pretty closely. And if your gage varies but your actual measured temp does not, then you should start checking for wiring, sensor or gauge problems. I have found with a 160 thermostat my 4.3 runs at 155-175 usually and only gets to 175 after coming off plane, then after idling for a few minutes it comes back to 160 or so.

 

[thumpar]

When the impeller was changed were there any missing pieces on the old one? It seems a tad high if it is reading correct but I would check like Lou C posted.

 

[Dillle209]

When the impeller was changed were there any missing pieces on the old one? It seems a tad high if it is reading correct but I would check like Lou C posted.

There were no missing pieces. 2 days prior it ran at least 3 hours exactly at 175 no movement .but went out for about 6 hours yesterday and the last hour or 2 is when it started to fluxuate but it wasn’t at the higher temp for long before i would go back down .cqn running it that high at short periods of time do damage to the motor?

 

[Lightwin 3]

The suspicious piece in this tale is the NEW thermostat. Just because it's new does not mean it is good.

Checking connections, etc, is always a good idea.