VX 2001 "overheating"

[Johnnz]

Righto car "overheats" sometimes around 80-100 but the moment I let abit more gas in and go say 105-110+ it drops down again, or pull over for a min it drops to normal temp. Cant find any leaks anywhere could this just be a wonky thermo? Radiator fans? Not sure where to start

 

[Aussie Trev]

Turn the AC on and check that the thermo fans come on. Does it stay cool with the AC on?, assuming the fans start up with the AC that is. Is there any water loss? Inlet manifold gaskets get tired and it can start sucking air into the system via the gaskets instead of coolant from the overflow as the engine cools which can them lead to an air lock in the cooling system. This can show up as small amounts of coolant loss, which stays in the overflow bottle instead of returning to the engine. Whatever it is it needs seeing to urgently before the engine cooks.

 

[Trevor loves holden.]

Its a process of elimination first be making sure your system is full of coolant, the next thing would be to see if the fans are working, once it warms up see if the top hose is passing coolant that would tell you its a sticky thermostat or not, then finally your water pump could be rooted.

 

[Johnnz]

Turn the AC on and check that the thermo fans come on. Does it stay cool with the AC on?, assuming the fans start up with the AC that is. Is there any water loss? Inlet manifold gaskets get tired and it can start sucking air into the system via the gaskets instead of coolant from the overflow as the engine cools which can them lead to an air lock in the cooling system. This can show up as small amounts of coolant loss, which stays in the overflow bottle instead of returning to the engine. Whatever it is it needs seeing to urgently before the engine cooks.

Im hoping its not this but its a possibility

 

[Johnnz]

Radiators still full top coolant hose full but just checked and 1 fan doesnt work. The one on the left doesnt spin with or without ac

 

[shane_3800]

It's not a fan issue 100% if it was a fan issue it would happen below 10km not at 80-100km.
I would first start with a radiator and engine flush to see if there's any crap in there. Then check if there's much crap stuck between the condensor and radiator if there is blow it out with an air gun.
After you do these two things check how it operates.
It seems to be overheating during highway lean out which sways me to thinking it's a system efficiency issue.

 

[BowTie]

Flush and replace waterpump and thermo and rad cap. These are dirt cheap.

Last waterpump I swapped had no fins left.

Once these are replaced, 90% of issues resolve.

Then rad.

 

[shane_3800]

Flush and replace waterpump and thermo and rad cap. These are dirt cheap.

Last waterpump I swapped had no fins left.

Once these are replaced, 90% of issues resolve.

Then rad.

If the water pump was the issue it would over heat at higher road speeds too. Water pumps when they loose the pump fins will overheat fairly quick at any road speed.
Thermostat is the same it will over heat at any road speed.

 

[Trevor loves holden.]

That picture showing high temp fan switching on so its reached over 114deg or there about, switch out the low fan relay and see if it fires up. The low fan should kick in at 104deg or when your A/C is on.

 

[shane_3800]

That picture showing high temp fan switching on so its reached over 114deg or there about, switch out the low fan relay and see if it fires up. The low fan should kick in at 104deg or when your A/C is on.

Neither should turn on at 80kmh.