12ht highway heating issue (1 Viewer)

[bootes]

Hey guys and girls, I've got a heating issue that is doing my head in. My temp gauge sits right in the middle for the most part, but on the highways it creeping up to more like 2/3rds maybe a bit higher up the gauge recently. I've have had a new radiator, water pump, genuine Toyota 82deg thermostat and 2 good reverse flushes of the cooling system. The viscous fan also appears to be working fine.

Highway driving is about 100-110km/h and it is sitting at around 1900-2100rmp which is what it normally is, and doesn't seem to be working particularly hard. I'm certainly no mechanic, but this has me stumped.

I'm starting to think the gauge is inaccurate, as most people say their 12ht sits at 1/3rd of the gauge and may go up to the mid point on a properly working gauge. Could it be that my gauge just sits roughly 1/3rd higher than it should? Has anyone had a similar experience?

Thanks in advance

 

[hj 60]

My hj does that uphill with a boat trailer, maybe a laser thermometer or other gauge is a start to investigate?
more info on 61 here:

help!! hot running hj61

I have a 89 HJ61 RHD 12ht and I have went through the whole cooling system from a new rad(re-cored) to fan cluch, thermostat(I tried 2 new ones 195 and 180, flushed system , timing checked, cooling system checked for exahust gases, valves adj. injectors checked, cooling system vac'd of all air...

forum.ih8mud.com

 

[Earwigg]

Mine sits at a third once warmed up summer or winter comes up a tiny bit up a decent hill and drops a almost immediately at the top.
New pump and original radiator with rotten fins.
Is yours an auto ? Another gauge to confirm as suggested above sounds like a good place to start.

 

[KeepCruzin]

Your gauge is certainly above the average temperatures I experience with mine. You could look into an inexpensive, standalone temperature gauge that displays the actual degrees digitally. You could mount it temporarily in your cab somewhere, and compare the degrees you see to the standard operation temperature in the 12HT manual. If its within reason, your gauge is probably faulty. You dont necessarily have to change it though, because youll know that when the needle is at 2/3, your engine is operating at normal temp. Thats a pretty inexpensive, low effort way to check your system.

 

[bootes]

Mine sits at a third once warmed up summer or winter comes up a tiny bit up a decent hill and drops a almost immediately at the top.
New pump and original radiator with rotten fins.
Is yours an auto ? Another gauge to confirm as suggested above sounds like a good place to start.

Yeah it's an auto. Do you know if it's the temp gauge sensor that would control the level of the gauge in the cab? If so they're only about $30, but i'm going to buy an infrared temp gun in the meantime to test it.