Another 2.4 overheating thread

[Canadian_Hilux]

This problem is really puzzling me and I was wondering if anyone has any ideas as to what the problem might be and any potential solutions. My truck is a 1991 2LTE with 163 000km the head has been replaced. 2 weeks ago I noticed my radiator had sprung a small leak along the top and coolant was leaking out when hot. I took the truck in that day (has never overheated at this point) and had a brand new radiator and transmission cooler (air cooled) fitted.

On my way home just as i reached the top of a hill and eased off the throttle my temperature rose just above the halfway mark. This has never happened to me since I purchased the vehicle in May 2010. I pulled over and noticed my radiator fan was on.(another first) I pulled over let the car idle for a minute before shutting it off. After letting it sit for 5 minutes it cooled back down and never heated up again. Today I was driving to my friends house going about 60-70km/hr and had the same thing happen so i pulled onto a side road and popped the hood. The vehicle cooled down to operating temperature in about a minute so I kept going. About ten minutes later. I drove up a big hill and the temperature stayed normal. Right as I reached the top of the hill and eased off the throttle my temperature rose again. As I drove home I played this same game the whole way home. It happened more frequently.

Heres what puzzles me. I'm not using any coolant. When the truck is "overheating" My coolant in the excess tank is at the same spot it always is when the vehicle is at operating temperature.

When I play loud music, flick on my turn signal, window wipers lights etc. Basically anything electrical "raises" the temperature on the gauge.

Sorry for the long drawn out post but this doesn't make sense to me. It's just to much of a coincidence this started happening right as I got a new rad and that theirs no other signs of overheating besides my rad fan coming on and the electric fan coming on. And the fact it never goes near the red, always to the top of the "normal" mark. Any ideas will be appreciated.

[imgifted86]

could your thermostat be sticking, or your water pump not pumping.

[TonyN]

I'd be tempted to fit an aftermarket temp gauge to be sure it's actually getting hot.

The gauge temp sensor and the fan temp sensor are different things, so unlikely to be both together, but if if electrical things seem to be setting them both off, check all the earth straps to the engine, especially the two big ones on each side of the front of the motor, one could have got left off or moved fitting the rad.

I wouldn't pay to much attention the level in the expansion tank, as long as its not overflowing, the level at the cap is more important, make sure that is full up and who ever did the rad didn't get any airlocks on refilling.

If you arn't actually losing coolant but it is getting hot then its not normally likely to be to much to sweat about, more likely to be something not up to scratch, like a rad, stat, viscous hub, water pump etc...

[Canadian_Hilux]

Thanks for the replies. The timing belt and water pump were both done 8000km ago so I doubt that's my problem. Water at the rad cap is full. I It wouldn't surprise me if the thermostat is sticking.

[Canadian_Hilux]

Had a new cap and thermostat fitted. It improved slightly but still goes a tiny bit over, and I think the gauge is a bit wonky. I think that the cooling problem was a combination of that this was the first very hot day of the year, the 33x12.5 mudders, the air restricting skidplate and loud music (Didn't have any of this last summer) all put a bit of extra strain on the system so it warms up a bit more then normal.