High temperature (1 Viewer)

[kiter18]

Hi
I use daily my LC fj80 1992 to go in the morning and return in the afternoon all days perfect.
I always go at more or less 37 miles in 12 miles distance.
But yesterday I went more far away and at more 57 miles/hour and the temperature indicator starts to go up
I put off the engine immediately before reach red signal
I return my trip again at 37m/h and no problem but if I start to accelerate in a hill or more speed , so it’s start again to go to the red part of the temperature sensor.
What could be ? What do you think?
Thanks Marcelo

 

[bhsdriller]

When's the last time the cooling system has been addressed? If not i'd go through it, can start with the basics coolant flush, thermostat, even water pumps are pretty cheap on these.

 

[Malleus]

The radiator should be full and the overflow bottle should have coolant in it between the marks on the radiator side.

The radiator cap serves to pressurize the system so that the coolant can work to maximum effect. The cap can leak; if it does, you will see coolant around the top of the radiator. The cap can be easily tested to determine if it can hold the pressure required (between 8.5 and 13 psi).

The radiator and A/C condenser both have to be clean and the fins have to be straight so that air can flow through them. The space between them also has to be clear (no trash or mud, etc), for the same reason.

The under cover below the radiator has a significant effect on the cooling capacity of the radiator, as does the foam seal around the outside of the radiator, between it and the frame. If either or both are compromised or missing, cooling capacity will be reduced and you may not see any effect on short trips.

The fan clutch is supposed to allow the fan to idle when the vehicle speed exceeds the speed at which the fan would pull air through the radiator. If the fan clutch isn't slipping at the speed it's supposed to, it'll reduce the amount of cooling air that can flow through the radiator.

If your engine was warm before you reached your 12 mile destination (I assume it was) and you had no overheating problem, I would rule out the thermostat.

In my experience, the water pump works as long as it is not leaking.

I'd recommend you check all these things and if everything looks OK, have the system flushed and the fluid replaced with new coolant.

These are the easy things to check and fix. If all this is OK, you have a coolant problem that will require more intensive diagnosis.

 

[kiter18]

When's the last time the cooling system has been addressed? If not i'd go through it, can start with the basics coolant flush, thermostat, even water pumps are pretty cheap on these.

Thanks
I think I will start changing the thermostat.
The liquid I change and clean radiator 2 months ago.

 

[kiter18]

The radiator should be full and the overflow bottle should have coolant in it between the marks on the radiator side.

The radiator cap serves to pressurize the system so that the coolant can work to maximum effect. The cap can leak; if it does, you will see coolant around the top of the radiator. The cap can be easily tested to determine if it can hold the pressure required (between 8.5 and 13 psi).

The radiator and A/C condenser both have to be clean and the fins have to be straight so that air can flow through them. The space between them also has to be clear (no trash or mud, etc), for the same reason.

The under cover below the radiator has a significant effect on the cooling capacity of the radiator, as does the foam seal around the outside of the radiator, between it and the frame. If either or both are compromised or missing, cooling capacity will be reduced and you may not see any effect on short trips.

The fan clutch is supposed to allow the fan to idle when the vehicle speed exceeds the speed at which the fan would pull air through the radiator. If the fan clutch isn't slipping at the speed it's supposed to, it'll reduce the amount of cooling air that can flow through the radiator.

If your engine was warm before you reached your 12 mile destination (I assume it was) and you had no overheating problem, I would rule out the thermostat.

In my experience, the water pump works as long as it is not leaking.

I'd recommend you check all these things and if everything looks OK, have the system flushed and the fluid replaced with new coolant.

These are the easy things to check and fix. If all this is OK, you have a coolant problem that will require more intensive diagnosis.

Thanks
The fluid I changed 2 months ago and also clean the radiator. I’m going to change the cap radiator and also buy a new thermostat and see what happens.
Because it’s rare only goes up the temperature when I do road after 1/2 hour at speed. If I go at 35m/h not problem at all.

 

[Malleus]

I recommend a genuine Toyota radiator cap. Also, testing the cap is a good time to test the cooling system ability to hold pressure (it's done with the same tool). This will help spots leaks, if any. And doens't cost what the parts do.

If the engine temperature does not rise above normal, after the period of time to "warm" the engine (5-10 minutes or 5 miles in city driving) then the thermostat is likely not the problem. If you are concerned about it, test it before you replace it.

 

[kiter18]

I recommend a genuine Toyota radiator cap. Also, testing the cap is a good time to test the cooling system ability to hold pressure (it's done with the same tool). This will help spots leaks, if any. And doens't cost what the parts do.

If the engine temperature does not rise above normal, after the period of time to "warm" the engine (5-10 minutes or 5 miles in city driving) then the thermostat is likely not the problem. If you are concerned about it, test it before you replace it.
View attachment 3267560

Yes
I’ll buy a new original cap.
Maybe the thermostat is not the problem
Because I think
If it reach normal working temperature and not goes up is that the thermostat let de water pass through the radiator normally
The problem is if I accelerate the motor more than 35m/h after a time in the road on a large trip.

 

[Malleus]

There should be a headgasket emoji...

 

[BILT4ME]

I would expect this to be a fan clutch since the temperature increase occurs when going faster and inducing more load.

It has been shown on these that the cooling fan engagement is needed more at higher speed than at lower speed.