Hot Start Temperature Issue Supercharged 1FZ-FE (1 Viewer)

[Fzj80 1997]

I have a supercharged 80 series and am having a temperature issue when I start the truck after driving a while with the engine warmed up. The truck is driving along just fine with the needle in the middle of the temp gauge for the most part. Sometimes it is a tick over the middle.

The issue is that when I go to start the truck back up after a long drive on a hot day, the needle will immediately shoot close to the red then immediately settle down to the middle after a few seconds. It has never gone into the red. The radiator was recently changed as well as the thermostat, but the problem still persists. The truck is topped off on coolant and there aren’t any leaks. I have another 80 and have owned several others and they haven’t done anything close to this at all. Has anyone ever experienced this or have an idea as to what’s going on with my truck? Thanks

 

[Fzj80 1997]

Here is a pic right after start up

 

[Wyatt Pine]

It sounds like heat soak. When an engine is shut off the temperature spikes for a short time until all the stored up heat in the engine that would be transferred to the coolant is used. Do you know if someone has done the resistor mod on the temperate gauge? This would make the gauge way more sensitive. Does it have the stock supercharger fan clutch or an upgraded fan clutch?

 

[Mjones]

It sounds like heat soak. When an engine is shut off the temperature spikes for a short time until all the stored up heat in the engine that would be transferred to the coolant is used. Do you know if someone has done the resistor mod on the temperate gauge? This would make the gauge way more sensitive. Does it have the stock supercharger fan clutch or an upgraded fan clutch?

Mine does same thing but only started after doing the resistor mod 93-97 Coolant Temperature Gauge Modification
Was concerning at first too.

 

[Fzj80 1997]

I honestly wouldnt be surprised if this truck has the mod from the previous owner. I guess I’ll take out the cluster one of these days and check and see if it’s been done. Thanks for the help guys. Also, Mjones, is your truck supercharged?

 

[Mjones]

I honestly wouldnt be surprised if this truck has the mod from the previous owner. I guess I’ll take out the cluster one of these days and check and see if it’s been done. Thanks for the help guys. Also, Mjones, is your truck supercharged?

Yes, mine is. With the temp mod the gauge will move up and down pretty accurately compared to scan gauge showing temps. But when I shut off and let sit for even a few minutes and then start back up it’ll show needle near red and scan gauge at 205 to 210. But within a 30 sec to a minute drive it flushes and returns back to 186 where it usually sits.