5.7L temp gauge problem

[tunacious]

The temp gauge on my 5.7L raw water cooled 260 mercruiser is reading all the way to the right even though the engine is operating at the proper temp, checked with a heat gun.The gauge moves up slowly as the engine warms and finally pegs. The dealer sez it needs a different sensor. This engine was new last year and replaced a 1988. Are there a variety of sensors? Also, there appears to be 2 sensors opposite each other on the thermostat housing but only one is connected to a wire? Just need to know if I should replace the gauge or the sensor/s.

 

[vipzach]

Re: 5.7L temp gauge problem

I would start with the temp sensor, they are usually less money and easy to do

 

[Northern Eclipse]

Re: 5.7L temp gauge problem

The second sensor is for high temp alarm is it possible you have the sender wire from your gauge hooked up to the Wrong sending unit? the wire should be on the sender on the starboard side, thats the way I see it on my 350 mag.

 

[rattana]

Re: 5.7L temp gauge problem

I had the same problem with my temp gauge pegging. You need to get a sending unit that matches the gauge. The sending units come in a variety of resistance values.<br /><br />Make a note of what kind of gauge you have and go to a marine shop, they will take care of you.

 

[Don S]

Re: 5.7L temp gauge problem

Just take the gauge sender out of the old engine and replace the one in the new engine. You may also find the oil pressure gauge is off.