Coolant temp normal operating range

[magicdeo]

Gday. Has anyone got a digital coolant temp gauge on a 4jb1t? I’ve had one fitted to my Ute for a few years now and I want to know what a normal operating temp would be. My Ute always sat just under halfway no matter what (when the standard sender was fitted) but with the new gauge, on a hot summers day working hard I can reach 105 degrees C. Ive checked/replaced everything I can think of over the last few years and the cooling system seems to be in good condition, maybe this sort of temperature is normal? The coolant never boils and it never seems to be an issue to the engine, I just want to get it sorted if it’s running too hot.

Cheers

[geeves]

15 pound cap means boiling point is 121C. 105 is no issue

[isuzurob]

All mine have run at around 65 degrees Celsius crusing at 100km giving it all it had max temps were 94 I ever saw on a 30plus day

[magicdeo]

Mine will never sit below about 83 even on a frosty morning which is no issue for me at all due to having an 82 degree thermostat. But going over 94 doesn’t take much work.
Geeves, although the boiling point is above this, how do I know that the engine will still handle those temps without issues?

Cheers

[geeves]

In theory they set the boiling point as a safety valve to prevent damage. The engine boils before it implodes. Theory is good anyway. I had my old 2.8 off scale without boiling when I wired an electric fan into the charging circuit then killed an alternator before a 400 meter walking pace climb no damage done. (I drove it for another 4 years) I had my wizard off scale for a short time when the fan pulley split throwing the belt. I sold that within a year but no obvious harm.
Certainly running near boiling is not a good idea and if normal running is getting you close you should be looking for the reason.
Fan requiring new viscous oil
Fins blocked with mud
core blocked with rust
waterpump corroded
timing out
injector issues
turbo issues
auto trans issues
aircon radiator blocked with mud
are all common

[BrianR]

Hi, This may be of help to members whose engines are overheating. Many thanks to geeves for his help. My motorhome with a 4Jg2 3.0l diesel engine experienced temperature increases on hills. I tried replacing the thermostat, antifreeze, flushing the radiator etc. geeves suggested the viscous fan. I removed the fan from the engine and carefully pulled it apart. A gentle tap with an impact driver to remove the 4 screws, be sure to mark the viscous fan before separating it. Drain the silicone oil and clean. My oil was was gluggy and the sealing ring had expanded. I purchased 60ml of 10000 cst silicone oil and a new o-ring. Filled the clutch with all the oil and reassembled, fitted it back on the engine and now I can cruise up steep hills without the gauge going up!
Prior to replacing the oil I found a clutch which fitted a patrol was very close to fitting my engine but was around $500, Repco staff also told me my clutch was fine as it had some resistance when turned by hand but I found at temperature the resistance was the same. Once again Thanks geeves. regards Brian

[geeves]

4 screws? Our 4wd ones have about 10 and no oring Otherwise its not a difficult fix