water light flashes now and then

[BobbyT]

hi, have just got my car back from the garage but for some reason the red light on the warter temp guage flashes now and then! anyone know what would cause this! its not over heating and the fan kicks in fine? cheers, rob

[rubjonny]

first thing to check is the water level is topped up.  If that checks out then the level sender may be about to pack in.  Bridge the pins on the plug, if this stops the flashing replace the sender, if it doesn't then you've got a wiring problem, or perhaps the dash temp sender is about to give up.  Its the black one with a brown & a red/yellow wire, located in the coolant flange at the front of the head.

[benmk1]

you haven't had the water dropped/changed have you? Just thinking could be an air lock......just a thought

[BobbyT]

had a new expansion bottle and sensor fitted, supose it could be an air lock! will see if i can sort it!

[BobbyT]

well i dont really know what the trouble is, now the guage goes right to the max level with the light flashing but as far as i know this cant be correct as the car is fine and the water level is ok and the fan works! maybe i should replace the sensor! 

[rubjonny]

Thats the black temp sensor for the dash gauge, my mate had exactly the same problem

[BobbyT]

so is it the sensor which fits in the bottle? 

[rubjonny]

No sorry, the one in the top rad hose coolant flange on the front of the head 
Should have a 2 pin connector with a brown & red/yellow wire (or perhaps only a single red/yellow wire on a MK1 GTI?)

[eyeletboy]

this is a long shot but i had this problem on my mk1 sportline.have you got braided hoses running over your rocker cover? if they are,move them so they are not making any contact with the rocker cover.this sorted my problem out.there was a short causing the temp gauge to flash and wander all over the place.

[BobbyT]

i will take a look later on bro!