1984 K10 Water Temperature Gauge Malfunction, Max Out Then Drops

[Joeyr60]

Hi, My 1984 Chevy K10 Silverado water temp gauge will max out within driving a mile or two, but then within a minute or so will drop back down to normal. I've read some of the posts in the forum, but haven't seen any with this exact issue. I had a lot of accessory work done to the 350 motor and this started occurring afterwards. I have changed the thermostat twice, filled with new coolant, and replaced the temp sending unit. The hoses don't seem to be overheating and the truck will run for long periods of time without overheating or having any problem. Is this a wiring or ground issue? Thanks.

 

[Tank6x2]

Check the eyelit connection clean it and restest it, could be the sensor, could be the printed circuit board on on the back of the cluster.

 

[Joeyr60]

Thank you. I will check those when I am home again. It just seems strange that every time I start it, the temp is fine until I get about a mile from my house, then it spikes and within 30-40 seconds, it goes back down to normal with no problem. I've already changed the sensor and ensured a good connection on back of gauge.