Temp light/Rad fan

[DarkPoet]

Ongoing temp light questions:

Flickers on & off when 55mph+ on motorway but engine never blown up - not even once Have cleaned the sensor in the header tank & changed the temp sender.

Prev thought electrical, now noticed that goes out when heater blower turned on so presume it is actually running hot. Not sure if elec fan is coming on. Have just run engine up to temp (needle sits just to right of light - light out) and then just left idling on drive for about 10 mins. Fan didn't come on but needle didn't rise any either.

How soon should fan kick in?

[colinthefox]

My temp light flickers whether the engine is too hot or not, but only when my mobile phone charger is plugged in and the phone is fully charged! And yes I have refurbished all the earth crowns. It also flickered in the past when the wiring to the level sensor in the coolant tank was corroded.

So your problem might not be due to the temperature of the engine at all, and may be wiring related. You could try the earth crowns behind the glove box first.

There is no hard and fast rule as to where the needle sits when the rad fan comes on. Just to the right of the LED could be normal(ish) and maybe half way to the "hot" mark before the rad fan comes on. Most temp gauges are now old and a bit variable.

It takes quite a while for the temp to rise enough for the rad fan to kick in if it's just idling. Essential to be confident it will come on though. I check mine every year just to make absolutely sure it's working OK.

[Dazco]

It took best part of 40 minutes at fast idle for my fan to cut in. Sounds likely to be a problem with wiring and earths .

[DarkPoet]

Cheers all - will give it a looking at