Temperature sensor malfunction?

[HoytAdickes]

So I've been having a overheating issue , but didn't make sense because all components are new. So here's the deal 2005 Volvo Penta 4.3 GL-D. Water pump, impeller, thermostat are all new. So sometimes it overheats according to gauge 225-250 when at idle speeds, but add throttle and temp Guage goes back to middle 175. Now it will also sometimes do it when at full throttle as well. So today I bought a digital infrared thermometer. Well the Guage shows way higher temps then thermometer does. Thermometer is correct I checked it to my hand temp. So gauge says 225, but thermometer says 140 at thermostat housing. What do yall think? Temp sending sensor?

Tried uploaded pics, but says files are too big

 

[alldodge]

Temp sending sensor?

Agree

Could connect a ohm meter to sensor, put it in a pan of water and heat it up watching the resistance change.
Cold 240 ohms, hot 33 ohms

 

[jerryjerry05]

Resize the pics, easy.


The sender could be the problem, the contacts can be a problem too.
Check the grounds, WD at the gauge.

Different manufacturers use different methods of connecting their electronics??
You probably don't have Volvo gauges, check the connections EVERYWHERE!

 

[HoytAdickes]

Gonna order a new sender. I would think contacts would cause inaccurate readings. Like they would fluctuate . The Guage takes time to get to 225-250 like it works properly. When I apply throttle it drops smoothly as well. I would think if it was a connection that it would be sparatic. I could be wrong though. I did pull the sensor today, and it was dirty/rusty colored. Took a wire brush on a drill to it. Cleaned it up like new. Reinstalled it, and temp didn't go over 225 mark like it normally would. Thermometer still reads 150 though. It's like the Guage reads higher then it should.

 

[QBhoy]

What’s the temp like on the risers ?

 

[jerryjerry05]

Did the sender have any #s on the sensor?
What part# did you install??
3852829 for single 872068 for dual station.

Customer a LONG time ago was redoing his system.(hope my memory's right???)
Bought new everything, the sensor he bought was for one with dual stations, it read hot until he changed it?