Thermostat

[reaper1064]

When driving the temp is ok but when stationary the temp rises until I set off again, is it the stat.

[StevenN]

How long stationary?

What is the state of your coolant and is your viscous fan working?

[reaper1064]

heats up pretty rapid when at lights etc. fan is worked off the belt, I have a couple smaller fans but not sure what they are for.

[tweak'e]

what gauge are you measuring the temp with?

could be fan, but also water pump, blocked radiator, egr stuck open and cracked head.

[BUSHWHACKER]

heats up pretty rapid when at lights etc. fan is worked off the belt, I have a couple smaller fans but not sure what they are for.

I think you need to find out how a viscous (clutch) fan works and maybe have a read of the 2.4 section.

[reaper1064]

Cheers for that Bushwhacker, after looking it up it all makes sense. The other day I noticed a leak under the truck in the position it would be in, looks like I have lost the fluid. Is this an easy job to refill or does it point to something more sinister. Sorry for being such a dunce about it all but this stuff is all new to me.

[reaper1064]

Right guys after being a total retard about viscous fans I realized what it was , and to top it all the fluid I thought I'd lost had nothing to do with it . Right my fan is turning ok, so does this point to something like the rad fan relay, as the fuse is ok. Just stabbing in the dark here.

[shokenore]

Locate the fan sensor under the thermostat housing.

Disconnect the sensor
Turn the ignition on
Rad aux fan will start.

Thus proving the fan fuse and relay are ok.
You could possibly have a dodgy fan switch.

Or there could be nothing wrong and the cooling system is doing exactly what it should do.
It gets hot then hotter then cools down.

You should get the actual temperature of the coolant accurately checked and not rely on the OEM gauge, but then it is a gauge to gauge temperature.


A few more specifics would help mind you.

[reaper1064]

Thanks for that will give it a go. The temp when at a standstill get very hot, borderline red. but cools quite quickly when in motion. Truck still drives well besides this.

[reaper1064]

Looks like it may be a faulty fan switch as when disconnected as advised nothing happened.

[shokenore]

Thanks for that will give it a go. The temp when at a standstill get very hot, borderline red. but cools quite quickly when in motion. Truck still drives well besides this.

If its borderline red then you are playing russian roulette you just don't know it yet.

[shokenore]

First port of call is to check the coolant level in the rad cap when cold.
Make sure the expansion tank has coolant in about 2/3 up should be fine.
Check the drive belts are ok.
Check the rad fins are clear of mud.

If you have any doubt over the coolant drop it and renew with fresh.
I use Toyota Red.
If the coolant is new drain it into a bucket and keep safe, and re use.

Get a garden hose and take off one of the heater hoses at the bulhead heater control valve and flush both ways till clear.

If you can be invested I take out the rad too and flush that aswell.

Then have a look at the viscous fan, again any doubt have a look at re-oiling.


The rad fan is a problem though.
Do you have a mutlimeter or test lamp?

[reaper1064]

Taking it to a mechanic mate today, realized that I'm on the edge when driving it so am not taking it out unless really necessary.

[Bogus]

The viscous fan may be turning, but is it turning fast enough? It seems to me that when stationary, air flow is not enough.

[shokenore]

The viscous fan may be turning, but is it turning fast enough? It seems to me that when stationary, air flow is not enough.

I agree.
The bi-metal strip is probably allowing lock up but without enough silicone oil there won't be a lot of friction to turn the blade.

Seems to me the OP has a few issues which will all contribute to the high coolant temperature.