03 Tspirit 2.0 Vvti Overheating

[phil76]

Any ideas. heater stoped blowing hot air yesterday. today it overheated, the water level was fine and the fan kicks in as normal.

[igormus]

Any ideas. heater stoped blowing hot air yesterday. today it overheated, the water level was fine and the fan kicks in as normal.

hello mate

- cooling pump drive

- cooling pump impeller key

- thermostatic valve

- air pockets belong to cooling system

- thermo sensor co-ordination with a real temperature of the coolant

Start investigating one by one

Cheers/Igor

[bestseany]

If the heaters have gone cold then I'd say it's the water pump.

[Druid Boy]

I'm no expert on the Avensis cooling system but they mostly work on the same principle so:

If the interior heater stopped working then either there is no coolant in the matrix or it is not circulating.

The coolant level is only 'indicated' in the expansion bottle. Does your radiator have a cap? If so check that the rad is full. If your coolant is too low it will not cover the thermostat and the thermostat won't be able to do it's job.

The thermostat 'decides' when to release hot coolant from the cyclinder jacket to the radiator to cool down.

If the thermostat isn't working (eithe rbecause it has failed or because it is not covered in coolant) the coolant 'trapped' in the cyclinder jacket will overheat without any loss of coolant level in the expansion bottle.

But this doesn't fully explain the interior heater not working.

Usually the interior heater is independant of the main radiator drawing coolant from the cylinder jacket. (I once drove about 150 miles with a split radiator top hose using the interior heater to cool the engine. I was nice and warm for the whole trip and didin't lose any more coolant as the thormostat never sent any water to the radiator to cool.)

Perhaps your water pump is no longer pumping, hence the lack of heat from the interior heater and the overheating? Perhaps your coolant level is too low to feed the interior heater matrix.

Have you checked that the system is pressurised when hot? With the engine cold, give a radiator pipe a squeeze. There should be some resistance but not much. Run the engine for a while and as everything expands your radiator pipes will become firmer until hard. Watch out though, they can be hot little beggars! no pressure = a leak somewhere which also means your coolant is escaping (or has already escaped).

If your system is full and not leaking then I reckon its the thermostat or the pump. Tell us what you find.