Good day from Hedland Australia!

i have a lovely 2000 Camry wagon, 400,000km. I’ve just had:

- Top end rebuild
- new radiator, ECT, temp sender, radiator switches

The temperature gauge always used to sit at 3:15 (where 3:00 is halfway) and now when hot sits at 3:00 to 2:45. Scan tool reads ECT at 98-100 when at 2:45, fans all come on, and using the thermo laser on coolant inlet and outlet reads 75°C in and 96°C out as averages.

inspecting under the hood the only thing I can see different from normal is that one of the ground wires has been connected to the exhaust manifold.

my question is more about wether anyone has had this problem too? I’ve driven it from Perth to Port Hedland (on road temps exceeding 70°C) and no dramas, no leaking coolant or anything.

possible problems I’ve come up with:
- should I replace temp sender and/or ECT with genuine Toyota parts?
- are the ground wires possibly incorrect?
- is the temp gauge most likely FUBAR?

any help is greatly appreciated.

 

Is the coolant temp actually changing with the temp gauge needle position? Meaning is the coolant temp OK but the gauge system bad?

Fans come on at around 199F.

 

toyomoho, yes the fans come on at the correct temperature, and the temperature gauge does go up and down depending on the temperature. The car for the past almost two decades always sat just below center. Forgot to mention it is a 5SFE motor, automatic (a fault in the auto transmission couldn't raise the temp??), and we've changed the thermostat twice on the assumption it could have been a faulty thermostat.

Checking the earth wire there are the obvious ones from alternator and battery. the chassis engine connections are two from the passenger side that go from a mounting point under the battery to the engine winch point, and on the drivers side there are two; one from the winch point and one connected to the exhaust manifold. My concern with the earth wires are that they are a very thin wire for earth, and if it's connected to an exhaust it would get hotter and that could possibly change the ability to be an effective ground?

 

Check wiring.

For the temp gauge in console, the Brown wire is ground. The Yellow/Green wire goes to the gauge input (to sensor).

Check sensor resistance. Should be 160-240 ohm at 122F.