thermo's going on and off

[edroders]

so the other night i noticed that the thermo fans on my s2 fairmont ghia 6 came on then went off agin after less than 5 seconds. i had been driving at 50/50 100k's and 70 - 80k's an hour for 10 minutes prior, but the temp needle was on the "N" in normal and it was late at night and about 15 -20 degrees. i pulled over and the hose from the radiator to the block on the passanger side of the motor was hot to touch but had very little pressure in it... so the question is : is the thermostat gone or worse? or am i just paranoid?

[Mr Hardware]

hard to say
i'd immediately guess paranoid given that your needle was on the n of normal
put your cluster into diagnostic mode and watch the temperature in digital degrees if you like
did you have the aircon on?

[edroders]

nope no aircon, i hope its just paranoia but the lack of pressure in the radiator hose worries me. having said that i haven't had a chance to check under the oil cap yet so hopefully its all clear

[mik]

the lack of pressure if its not looseing coolant might be a dodgey radiator cap problem, x the fingers .

[edroders]

update. i checked under the oil filler cap and it is as clean as you would like it to be. so i decided to run the car with the heater on trying to get its temp up and the thermo fans came on well before the engine was at temp. the needle on the temp gauge was just past the first line well before the normal range..... is this normal? as this is the first time i've done this to this car. thanks guys.
oh and i fairly sure the thermostat is working because when i squeezed the top radiator hose i could see the effect in the header tank...

[mik]

if the temp is running ok i`d say your you don`t have a problem with the fans , it was night time so theres not much effort for the fans to keep the motor cool(hence the short fan time), if they were not working the first traffic jam you`d know about it, however for the lack of pressure in the cooling system(and peace of mind), for a small pay out at radiator place you could do a cooling system pressure test, they can also test your radiator cap, or just buy a reservoir cap/radiator cap and keep an eye on the coolant level.

[edroders]

thanks mik, the coolant level is fine so i will have it pressure tested and the cap looked at

[Mr Hardware]

yeah i think mik has the best ideas
go down to red devils and get them to do a pressure test, if it comes back ok then just buy a new cap, they're cheap and they do go
i'd be worried if it was the other way around, ie fans not coming on enough when the car is hot rather than coming on maybe too much when the car isn't too hot