88 FJ62 Dash Temp Gauge Help (1 Viewer)

[1munk]

Hi all,

Just finished changing the following on my 88 FJ62. All parts are from CCoT.

• water pump
• hoses
• belts
• thermostat
• aftermakert dash temp gauge sender
• radiator cap

pretty sure all is burped sufficiently but not 100% certain. No leakage

Despite being a bear of a job, it seemed to go well except for two things:
1) wire to the connector attached to the water temp switch #182-67 below (top of the thermostat housing not the dash temp gauge sender at the bottom of the thermo housing #182-12 below) broke but I soldered it back together

2) dash temp gauge is reading much higher than before but previous sender looked pretty old. I’m checking the word housing and block temps after running the engine with an IR thermometer and the temps are 165 which is well within the safe zone as far as I can tell.

Can anyone tell me what the water temp switch does? Could this be the cause of the higher reading on the temp gauge now?

Found this older thread but it isnt for a 3FE so not sure if I have the same situation. the 62 sender is at the bottom of the housing so I’m having a hard time thinking there could be an air pocket there.
2f Temp gauge sender burping

thanks in advance!

Scott

 

[kbfj621989]

Burp it again.
What type of coolant/mix did you use?

 

[1munk]

Prestone 50/50. Would the type of coolant make a difference?

thx

 

[OSS]

Although there won't be any lodged bubbles interfering with the temperature senders in the thermostat housing, there likely are stuck bubbles in the head. Eventually the engine will purge them out on its own (after a few weeks of daily driving) but it's no fun seeing the gauge like that. Burp it some more.
The sealed cooling system can only burp a little air during the warm up time of the engine. Once the engine has reached operating temps, burping is over (until the next cold start).

 

[1munk]

Thx Oss, it is a bit scary but I’ve tested it with the IR gauge and it is fine so I will try to ignore what normally would be a big red flag. appreciate the help

 

[g-man]

temp switch=temp sender. basically resists current on the ground side of the circuit in ohms based on the temp of the sender. You can test the sender with an ohm meter. this from a 84 body and chassis FSM is for a 60 series

 

[1munk]

Thx g-man. That helps

 

[dogcruiser]

temp switch=temp sender. basically resists current on the ground side of the circuit in ohms based on the temp of the sender. You can test the sender with an ohm meter. this from a 84 body and chassis FSM is for a 60 series
View attachment 2119525

@g-man how do I know if I’m at 122F or 239F? Is there a reference resistance when the engine is cold?

 

[EscapeWagon62]

I had the same.
Jacked up the front of the truck
Ran it with the cap off and a rag for a couple minutes
Fixed
hope that helps
cheers

 

[Michael Hanson]

Hi, Make sure both heaters are on when you do this.Mike