My rad fans don't come on when the engine is hot (I've used to torque app and it doesn't come on even when that's showing 96°C+, though I always take that with a pinch of salt) - I've jumpered the terminals that connect to the fan switch on the radiator, and they operate fine then, so I'm fairly certain a new switch is in order. I'm not too worried, as the car's temp gauge has never gone past 90, but as I intend to flush and replace the coolant soon I think I might as well change it.

 

But during my investigations, I've noticed that even after a long drive, the front face of the radiator feels cool, but the back face is scalding. Is this normal? I kind of expected the front to feel at least warm, and if the fan switch is picking up a temperature near this, it could explain why the fans aren't coming on

 

cheers

as far as I can remember fans wont kick on til temp hits 100

The fan behaviour is perfectly normal.

 

I've never studied the temperature gradient across the radiator fins, but I'd expect the air coming out of the radiator ("behind" it probably unless the car has been standing for several minutes) to be hotter than that going in, which would logically suggest that the fronts of the fins would be a bit cooler than the backs.

The fan behaviour is perfectly normal.

 

I've never studied the temperature gradient across the radiator fins, but I'd expect the air coming out of the radiator ("behind" it probably unless the car has been standing for several minutes) to be hotter than that going in, which would logically suggest that the fronts of the fins would be a bit cooler than the backs.

 

Yeh I wouldn't have been surprised if it have been bit cooler, as obviously the front is hit with cool air first, but it was just that the front was pretty much cold, and the rear so hot I could only touch the metal for a couple of seconds. Perhaps I'll leave it to stand for 10 mins after I next drive it and see if it equalises out a bit

 

as far as I can remember fans wont kick on til temp hits 100

 

I've read on here low speed should kick in at 92°C - although I have also read people have owned their cars for months or years and only had the fans kick in once or twice! perhaps I'm worrying over nothing...

Mine are always kickin in wen ive pulled up at junction or set of lights maybe only for few seconds at a time never seen temp gauge go above 90 in over 12 months

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As long as your moving, the air flow is enough for the rad. Fans are only there to compensate for the lack of air movement when stuck in slow stop start traffic with a hot engine.

Mine are always kickin in wen ive pulled up at junction or set of lights maybe only for few seconds at a time never seen temp gauge go above 90 in over 12 months

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That's the other thing; the temperature guage is "stabilised" so it always reads 88C when you go over 75C and under 105C. 

That's the other thing; the temperature guage is "stabilised" so it always reads 88C when you go over 75C and under 105C. 

exactly with modern cars so it doesn't worry drivers.

 

Had an old alfa and the gauge was a real one and fluctuated a lot. You could see the temp rise quickly in traffic to 90, then hear the fans kick in and slowly fall to 80.

The modern gauges have a range where they don't move, maybe 85-95 approx

Fans should run on low speed all the time with air con on

Fans should run on low speed all the time with air con on

 

Only ONE fan (the smaller one) runs all the time with the aircon on...

Both run with air con on in my vrs

Yep both run in mine with aircon on

Same here, one of your fans is up the duff

Both run constantly on mine too. Definitely a faulty fan there.

That's the other thing; the temperature guage is "stabilised" so it always reads 88C when you go over 75C and under 105C. 

 

I figured this out a while ago whilst using Torque, I'm wondering though...Is it possible for this to be changed with torque or something? I'd much rather see the real temperature.

Oh. Weird then. On mine, one of the fans runs constantly with the aircon on, and the other cuts in when the engine gets hot, sat in traffic or whatever...?

May be a controller fault on the low speed side of your large fan - from memory there is a vid on youtube to check out a golf controller which is basically the same system.