ln106 overheating

[Fletcher811]

hey fellas I'm new to site this has probably come up a million times i wouldn't no where to start to find some good information on this topic so ill shoot.. I'm currently driving a 94 hilux 2.8 standard diesel ute for some reason in colder days or nights i don't see my temp get anywhere near half way so this is a good thing i can give it a hard time up hills on the highway no problem apart from being a slug.. the minute the weather warms up it tends to start climbing up in temp i have had it boil on me twice that i know off lol. so far i have changed new radiator new thermostat new radiator cap new viscous hub and fan and I'm still not getting any results when the weather is a little warm i also put my old viscous hub on and tapped a screw into it so i had the fan on continuously and still nothing tried driving no thermostat and got nothing better... also i have no oil in water or no water in oil I'm not getting bubbles out the rad cap whilst the caps off and running. hoses are rock hard under pressure don't no if thats normal or not I'm clueless to whats going on there any info or advice would be great cheers

[Mud Dog]

You've looked at almost everything except the pump. Now they don't just normally fail but it's no impossible.

The symptoms you give are typical of a radiator that's on it's way out or the fins are blocked with insects / debris and the radiator just can't cope with the extra load when the weather is warmer. The thermostat is sometimes also a culprit by not opening fully and restricting flow. However, you have replaced both of these as well as the fan which can also contribute.

This leads me to think that either the new thermostat is a dud, or there is an internal restriction in the water galleries or the pump is lacking the ability to move the coolant fast enough.

Something else to consider is fuelling - if the fuelling is incorrect, diesels will get unnecessarily hot.

[Fletcher811]

cheers mud dog and iv tried also drilling 4. 3mm pilot holes on outer thermostat to get a higher flow still nothing on that aswell i always thought when a water pump goes it goes. I'm getting this temp riser more at a higher speed so is it possible the pump may not be able to keep up like it use too or am i tripping...

[Mud Dog]

I'm not sure what the pump impeller material is on your model, but metals corrode and some synthetics erode. Whichever, if the impeller blades wear down, the pump is no longer as effective. It may be worth checking out.