Thread: viscous fan on a TD5

Originally Posted by nedflanders

The fan doesn't lock up, so overheats in traffic, also it used to have some resistance when cold, now it just spins freely.

In what way does it overheat? Blows coolant, LR temp gauge reads high, aftermarket temp gauge reads high etc.

aftermarket temp gauge starts rising higher than normal when driving slow/towing the camper trailer. The sensor is on the cylinder head and reads head rather than coolant temp. The factory gauge I don't bother with as it's as useful as tits on a fish! Usually I know theres a problem when the aftermarket gauge starts climbing, if I speed up then temp drops indicating the fan isn't locking, which I can normally hear.

Is the temp sensor bolted to the head near the back on the passenger side?

What sort of temp does it rise to? Does it just keep rising, or does it stabilise?

Originally Posted by nedflanders

aftermarket temp gauge starts rising higher than normal when driving slow/towing the camper trailer. The sensor is on the cylinder head and reads head rather than coolant temp. The factory gauge I don't bother with as it's as useful as tits on a fish! Usually I know theres a problem when the aftermarket gauge starts climbing, if I speed up then temp drops indicating the fan isn't locking, which I can normally hear.

Sounds like you've had a problem and then fixed it by creating a bigger one.How do you know what the cylinder head temp is supposed to be?,is the factory gauge rising?,is it blowing coolant out of the header tank?.If the cooling system is as good as describe you shouldn't have over heating issue's,I think your chasing ghosts. Pat

The temp sensor is bolted to the front of the head where the top rad hose is, I'm used to seeing 80-82 deg C on that with coolant temp (reading nanocom) 91-92. Maybe your right Pat, probably chasing ghosts, since ambient temp is starting to rise (and all the work upgrading the coolant system was done in the winter) I just need to get used to a slight rise come spring/summer.

You say your use to seeing 80-82*C head temp and 91-92*C coolant temp, but what are you seeing when it is 'overheating' ?

I've got my head temp sensor near the back of the head, and this reads within 2-3*C of what my Nanocom reading is.

Without towing I'll see temps of upto 94*C, this is in traffic, slow speed driving, highway. This is with ambient temps in the low 40's.

With the camper on the back it will go upto 96*C on long hills, also if dropping from 100kph limit down to 60kph it will rise upto 96*C But then drop off again. I put this down to reduced airflow through the engine bay and heat soak from the turbo.

My cooling system is standard, original 2003 radiator, but all hoses, thermostat, coolant cap and viscous fan replaced in the last 12 months.

As Pat says I think you're looking for a problem that doesn't exist, hence my previous questions

90-92 is perfect Tdi,Td5,TDCi operating temp. Pat

To add,I'm in two minds about extra sensors on vehicles,too many times people fit them and then watch them like hawks worrying about stuff they shouldn't be,the temp gauge is a good example.Temperature gauges on all vehicles are desensitized,they have to be or they would never stay still,dealerships would be over run with people complaining about the gauge going up towards the red driving up hill and then going down towards the blue cruising down the other side,keep the cooling system in good condition and use common sense while driving and all will be good. Pat