Club 80-90 Forums

This summer the 1st rad fan has been coming on fairly swiftly in traffic....only 5/10 mins of idling.

I'm assuming this could be the radiator on it's way out? I'm assuming it's the 1982 original and will be very inefficient with age

All the rest of the cooling system is fine. No air, no leaks, etc etc

Could equally be the thermostat not fully opening or the fan switch cuttng in earlier
cheaper to try these first

Thermostat not opening fully wouldn't lead to a hot radiator, therefore wouldn't cause the fan to start! It would cause a hot engine. (think about it)

Cruz wrote:This summer the 1st rad fan has been coming on fairly swiftly in traffic....only 5/10 mins of idling.

I'm assuming this could be the radiator on it's way out?

I'm confused....because you are describing exactly how a correctly working system should operate....I presume the needle is just past half way when the fan kicks in? and then the fan stops on for around 30-45 seconds taking the needle back to half way (over the LED) ? Yes....sounds absolutely as it should be to me.

I also assume that the fan doesn't generally come on whilst driving normally? only when is slow traffic (as a rule) but not strickly..again if so then it all sounds fine to me

If the rad is blocked expect to see a higher needle reading before the fan is kicking in, due to the poor circulation in the rad and the hot coolant not reaching the thermo-switch efficiently.

Martin

Martin

Oldiebut goodie wrote:Thermostat not opening fully wouldn't lead to a hot radiator, therefore wouldn't cause the fan to start! It would cause a hot engine. (think about it)

I did think about it and came to the conclusion that if there was less flow rate it would still get the hotter coolant from the engine similar to a partially blocked rad

I am only questioning it as the rad fan comes on fairly quickly in traffic. possibly its the warmer conditons we have had this year and assumed the rad had become inefficient with age

I wouldnt be worried Cruz.... it has been much warmer recently, the water inside the cooling system runs at around 90-100 deg normally, as it rises the fan comes on to keep it lower, if the ambient atmospheric temp is 28 deg ( ten deg higher than we are used to here in Sunny England ) then there is less cooling effect available when stationary... so fan will come on earlier time wise. I think it would have been useful if VW had put temp readings on the guage , as other manufacturers do , that way people woudnt get quite so worried about where the needle was.

Cruz wrote:I am only questioning it as the rad fan comes on fairly quickly in traffic. possibly its the warmer conditons we have had this year and assumed the rad had become inefficient with age

It's still an air cooled engine (indirectly) if the ambient air is hotter the less it will cool the engine so the fan has to run more.