Supra Overheating - Need help

[Vios-GT_07]

just to clarify.. if it's a belt slipping, u can adjust the tension on it.. and yea if it's slipping u'll hear it screeching its tits off.. (slipping can be from seized pulleys and insufficient tension)

sorry to say i'm more of a clutch fan person.. easy to fix and u'll know straight away if it's got problems.. i hate thermos just becasue of the noise (i like the old clutch type roar for some reason.. and on a rotary it whirrs like an airplane)... and thermos have electrical (issues) .. so yeh. hehehe

[Vios-GT_07]

There's no bypass pipes for the thermostat in the Supra. Radiator straight to the Thermostat.

Will check the pump for slippage tonight.

after that i'd suggest just taking the thing apart and replacing the water pump if you haven't done it recently.. are u due for a timing belt by any chance? may as well do it all at once

not too sure but is the water pump running off the timing belt on this? or just the crank pulley?

[takai]

Everything seems to point towards the water pump being fubared... i would be going with that.
Remember higher temps == higher pressure == harder to pump.

[Norbie]

Remember higher temps == higher pressure == harder to pump.

I'd disagree with that - the pressure in the cooling system is regulated by the radiator cap, regardless of the temperature. Also the water pump is not affected by system pressure as it sees equal pressure on both sides of the pump.

It does sound like a problem with the pump though, eg corroded impellor. Pity it's a bastard to get at on a JZ engine.

[Vios-GT_07]

so the water pump is connected to the timing belt?

[EldarO]

just to clarify.. if it's a belt slipping, u can adjust the tension on it.. and yea if it's slipping u'll hear it screeching its tits off.. (slipping can be from seized pulleys and insufficient tension)

sorry to say i'm more of a clutch fan person.. easy to fix and u'll know straight away if it's got problems.. i hate thermos just becasue of the noise (i like the old clutch type roar for some reason.. and on a rotary it whirrs like an airplane)... and thermos have electrical (issues) .. so yeh. hehehe

wait till you hear a 7M roar ahahahah, sounds like a truck!

yeah the water pump is off the timing belt from memory, i could go outside and check, but i think its like that.

so what happens when you fill the radiator up? are you losing water? or is it full, and still overheating? sounds like a ghey radiator.

Eldar.O.

[BlackSupra]

It does sound like a problem with the pump though, eg corroded impellor. Pity it's a bastard to get at on a JZ engine.

2JZGE impellor is plastic from memory.

[Norbie]

yeah the water pump is off the timing belt from memory, i could go outside and check, but i think its like that.

Nope, runs off the accessory belt. You do need to remove the timing belt to remove the pump though, which makes it a bastard of a job.

2JZGE impellor is plastic from memory.

Not all, I've seen plastic and steel.

[Kagetsu]

I'll have a look tomorrow when I have some time. I suspect it's the fanbelt. The waterpump is driven off that, the only thing the timing belt controls is the.

[cambelt]

it is a bypass thermostat and with it removed it will overheat period, fit a new toyota one
Dave

[Kagetsu]

I'll head into Toyota tomorrow and get a new one... Just seems odd to be behaving the way it does. I actually didn't overheat as quickly with the thermo actuator removed.

[thu187]

I'll head into Toyota tomorrow and get a new one... Just seems odd to be behaving the way it does. I actually didn't overheat as quickly with the thermo actuator removed.

I've got the same problem in my 4agze but the engine is going into another car and I'm only using it for short trips so I'm not stressed.
Started happening after I got the car back from the mechanic. It will reach normal operating temperature in about the 1/3 of the time. If I'm not moving the temp rises steadily and will lower just as steadily when I'm moving.
Weird

[Vios-GT_07]

that sounds like ur fan's buggered.. or ur thermostat's not working properly..

[Kagetsu]

Just looked at the engine itself... It's definantly not bypassed anywhere. Hose right out of the radiator, straight to the thermostat coupling. There's tiny hole in the thermostat (about 2mm diametre) but that's hardly enough to make any difference to even the normal pressure.

[AndyTTR]

there might not be extra pipes on the outside of the head for the bypass, it could be internal. Again on the 3S there are no bypass pipes going directly into the thermostat, they go into the side of the water pump and are directed towards the back of the thermostat from the inside. I've not changed the thermostat on the Supra before so I couldn't tell you for sure.