1986 Toyota Pickup Engine Temperature Gauge Fluctuates

DAVID19864X4

MEMBER
1986 TOYOTA PICKUP
4 CYL
4WD
MANUAL
115,000 MILES

The engine temperature gauge fluctuates. I have the 2.2RE engine. About 1 year ago, the temperature gauge would occasionally go from normal reading (mid range) to redline, than return to normal within a few seconds. This seemed like a bad thermostat. It does this while driving at constant highway speeds, at stop lights, etc.

I replaced the thermostat and sensor. The situation has gotten worse over the past few months, the needle continually moves up to red line, than returns to mid range.

Is the mechanic thinks it may be the gauge itself. What do you think?

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Could be the fan clutch assy- When you replaced the Stat -did you bleed the cooling system properly could be very well be the idiot gauge-

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.