1HZ problem......

Reiner Hi,you are not alone with what you say ,our little Zuk was/is doing the same thing. I noticed it on our last rtip out to Eulo 7 Currawinya NP at Easter.We have rebuilt motor, new radiator thermostat hoses so do not know what the reason is. will watch the replies as well.
Cheers Bob.

Viscous fan needs attention ?

Hi All,
Back in the olden days when temperature guages were all capillary tube operated and not electronic gizmo's it was very common for the temp guage to rise after the motor was turned off, often into the red band.
Once you started again, the temp guage rapidly returned to normal

What actually happens is that the water temperature continued to rise for a while once the cooling fan and pump stop and because the guage continues to register, it indicates a rise in temperature.

In your case your guage is showing this increase of temp when you turn the key on after the 10 minute stop.

The reason that this does not happen when you have been stopped for a longer period is that the motor has had time to cool down.

I would watch it but there is no real reason to be concerned at this stage.

Hope this helps

Disco

viscous coupling as said
and regardless of what some pepople say just adding some silicone to the fan hub can not gaurentee its still good
cheers

Ok, try going up a long steep hill at speed. If it goes into the red, and then goes down when idling, its probably the viscous fan. Pick a hill you could normally go up without overheating.
The fan unit can be carefully taken apart and re greased using the special Toyota grease (which isn't that expensive) or a changeover unit installed.

its called radiant heat, dont worry about it.

Reiner

The assurances above all make sense. However, I have a 1997 80 series with 1HZ and it's temperature gauge has never done that, even in stinking heat and towing a caravan.

I'd keep looking for a cause.
Max

Change the sender unit in the head...that will fix it i believe.....not a motor problem but a sensitivity problem with the electroics....

Not sure if this will help but my 80 diesel had an overheating problem on long slow uphill grades towing a camper. The effective solution was to add extra oil to the viscous hub and to replace the hoses. The bottom one, if old, can suck itself thin and constrict the flow of coolant. Now no problems.

Reiner,
I had the same problem with my 80 series. They replaced the thermostat.
The thermostat ended up beeing jammed open i think. While the guys were there they also reco the viscous clutch fan as well. Problem solved for around $200.
No problems since.
Hope this helps
Don