So I have a bit of a funny one and have done some searching but nothing really putting my mind at ease. Is it possible that the viscous fan clutch/hub is working too well?! As in is running too often or pulling too much air (if there is such a thing?) Below is some context to my question:
2003 Aus spec UZJ100 5sp automatic, Radiator is brand new (koyorad), with new coolant. (was replaced when original 16 year old rad sprung a leak - not because of any apparent cooling issues)
Thermostat condition is unknown, however car warms up normally to 88°(190° for my US friends), then holds within normal ranges of 85°(186°) to 88°(190°), with normal driving. I have seen it briefly hit around 90°(194°) once when I was stuck in some traffic but thats as warm as ive seen it. So I believe it has an 88° thermostat that is working as it should.
The viscous fan hub condition appears good, testing it with warm engine immediately after shutdown the viscous hub is firm/fan does not freely spin. Cold start up fan locks up and spins with engine for about 10-15 seconds then slows down (which I understand is normal for cold start up while all the fluid circulates in the hub)
Now this is where the funny bit comes in. The car does not overheat, in fact what has me looking into it is it seems to run a bit too cool, and the fan seems to lock up with the engine all the time during normal operation, even when it is running below normal temps.
For example, I just arrived home from a trip up the mountain, inlet air temps were between 11°(52°) and 18°(65°) most of the trip and the temp sat around 86°(187°) most of the way, however on the way back down the hill I left it in 3rd and coasted all the way back down (about 10km windy road top to bottom). Now while observing the temps and fan operation, I noticed that the viscous fan seemed to be locked up with the engine revs the entire time, the inlet air temps were slowly rising as I got further down the hill, however the engine coolant temp was steadily dropping...
At the bottom of the hill, still in 3rd, viscous fan roaring away, inlet temps were just over 20°(68°) and engine coolant was sitting at 78°(172°)!
Went back into drive, back up to 100kph and temps went back to normal of about 86°.
Am I just freaking out about a super efficient cooling system?
Is it normal for the viscous fan to run that much? (or maybe constantly when in a lower gear, which would be odd I thought seeing they are purely temperature driven?)
I have noticed that more often than not when I slow right down and transmission drops back to first, when I start to accelerate again the viscous fan is often engaged, and when it is engaged there is a noticeable load on the engine - thats the thing out of all of this that has me wondering, as clearly I dont have overheating problems at this rate!
2003 Aus spec UZJ100 5sp automatic, Radiator is brand new (koyorad), with new coolant. (was replaced when original 16 year old rad sprung a leak - not because of any apparent cooling issues)
Thermostat condition is unknown, however car warms up normally to 88°(190° for my US friends), then holds within normal ranges of 85°(186°) to 88°(190°), with normal driving. I have seen it briefly hit around 90°(194°) once when I was stuck in some traffic but thats as warm as ive seen it. So I believe it has an 88° thermostat that is working as it should.
The viscous fan hub condition appears good, testing it with warm engine immediately after shutdown the viscous hub is firm/fan does not freely spin. Cold start up fan locks up and spins with engine for about 10-15 seconds then slows down (which I understand is normal for cold start up while all the fluid circulates in the hub)
Now this is where the funny bit comes in. The car does not overheat, in fact what has me looking into it is it seems to run a bit too cool, and the fan seems to lock up with the engine all the time during normal operation, even when it is running below normal temps.
For example, I just arrived home from a trip up the mountain, inlet air temps were between 11°(52°) and 18°(65°) most of the trip and the temp sat around 86°(187°) most of the way, however on the way back down the hill I left it in 3rd and coasted all the way back down (about 10km windy road top to bottom). Now while observing the temps and fan operation, I noticed that the viscous fan seemed to be locked up with the engine revs the entire time, the inlet air temps were slowly rising as I got further down the hill, however the engine coolant temp was steadily dropping...
At the bottom of the hill, still in 3rd, viscous fan roaring away, inlet temps were just over 20°(68°) and engine coolant was sitting at 78°(172°)!
Went back into drive, back up to 100kph and temps went back to normal of about 86°.
Am I just freaking out about a super efficient cooling system?
Is it normal for the viscous fan to run that much? (or maybe constantly when in a lower gear, which would be odd I thought seeing they are purely temperature driven?)
I have noticed that more often than not when I slow right down and transmission drops back to first, when I start to accelerate again the viscous fan is often engaged, and when it is engaged there is a noticeable load on the engine - thats the thing out of all of this that has me wondering, as clearly I dont have overheating problems at this rate!
