Hey Guys,


Ive been having issues with the temp gauge rising mainly when driving up hills the temp gauge will rise ,

then when driving on flat road it goes back down to half way ,

and now temp seems to rise after driving 30mins or so into the 3/4 mark. (then im normally where i need to be and shut it down)


The heater core intake and outlet hoses where leaking 2 months ago and when trying to change them they heater core fittings disintegrated so it got bypassed.

the radiator was replaced about 6 months ago , no current coolant leaks , Coolant was replaced then the hoses where done.

Have done an oil change 2 weeks ago , no Milky oil

Thermo fans , the one on the passenger side i have never seen spin , the one on the drivers side kicks in when the temp reaches 1/2 and turns off and on as its controlled by a temp sensor. when ever ive asked about the passenger side ive been told it only kicks in when the ac is on, is this right? ( im sure ive had the AC running and still never seen it kick in)


could it be the thermostat?, Thermo Fans?, blockage?

I own a 99' KH Verada and unless I'm dreaming, the fan on the passenger side of the car is the main cooling fan, or "thermo" fan

In my car this fan alone cycles in and out whilst idling at running temperature with the A/C off to keep the motor cool
If I'm running the A/C, the drivers side fan will run when the compressor cycles in, and then stop once it cycles out, but the thermo fan runs on its own crusade regardless of what the aircon is doing

From what I've read on the forums, the thermo fans can just fail from old age, and the reason you're seeing the drivers side fan run with the A/C turned off might be "stage 2" cooling where the ECU runs this fan because the primary thermo fan isn't enough to cool the car, or isn't running at all in your case :D

Like I said, I could be dreaming but just my 2 cents worth

Cheers,

i think ive read that in a old thread somewhere as well, ill try and find the relays , swap them around and see if i can get the passenger side to move , might need a new fan by the sounds of it.

As the heater core sits above the ecu, any long term leak may damage the ecu which controls the thermo fans. I have a KH as well with the same problem and have traced it back to the ecu.

Had a very similar situation to you about 12 months ago.
Turned out to be the thermostat. Seems to be an age related thing, and reasonably common.
Also, flush out the line between the radiator and coolant tank while you are at it.
Clean the coolant tank also, as a lot of "stuff" collects around the screen at the bottom, which eventually blocks it and prevents coolant returning to the radiator. I simply disconnected the line (at the rad) and shoved a hose into the coolant tank for a while (10-15 mins)...amazing the amount of cr@p that came out, and fixes both problems at once!

Had a very similar situation to you about 12 months ago.
Turned out to be the thermostat. Seems to be an age related thing, and reasonably common.
Also, flush out the line between the radiator and coolant tank while you are at it.
Clean the coolant tank also, as a lot of "stuff" collects around the screen at the bottom, which eventually blocks it and prevents coolant returning to the radiator. I simply disconnected the line (at the rad) and shoved a hose into the coolant tank for a while (10-15 mins)...amazing the amount of cr@p that came out, and fixes both problems at once!

I have replaced the radiator, coolant sensor, thermostat, radiator cap, water pump. I have flushed out the entire system especially when the water pump was out, as a matter of fact my cooling system is now at its peak meaning that i can drive the car almost 20kms in urban traffic, without cooling fans running and the needle sits in the middle, at night i get a better range but i still need to engage the A/C to ensure when the needle starts to rise to bring the temp down quickly. Having said all of that I checked every single related relay, fuse and thermo fan, they all check out ok. I even pulled out the main fuse, attached my multimeter to it hoping to see a voltage when the fans were supposed to kick on. I recieved a weird reading on the multimeter for a split second, then nothing, in other words there was no signal from the ecu side which should have activated the really. The power transistor in the ecu that controls the fans I believe has died from possible water damage from my heater core which is positioned above the ecu. So unfortunately for me my problem was different to yours as I really wished it was only as simple as your fix.