Mk2 GTI 8v temp gauge - goes up to max!

[dubchaser]

Hi

I've just got an 8v Mk2 GTI.  When I start it up the temperature gauge goes up to max within a couple of mins and the little red light in the middle flashes.  Anyone know why, what parts I might need and how much they might cost?

If there is a thread about this already can you post up the link?

Cheers
Lee
www.olds-cool-golf.co.uk

[Horney]

Either your car is overheating horribly and quickly (Would seem unlikely) or the switch the tep sender is knackered. Check it isn't shorting out anywhere as this typically causes this kind of problem.

Nick

[Mr Blue]

would of thought its your waterpump.

Does your heater heat up quickly when the temp needle goes up?

[dubchaser]

The guy who had it before me fitted a new water pump.  The heat inside the car heats up quickly when the heater facia slide is on max.  The temp light flashes and the needle rises slowly to the temp max within a few mins.

[Mr Blue]

thermostat?

[rubjonny]

I've heard you can get similar symptoms if the expansion tank level sensor is unplugged, check the wiring to it for damage, and try removing the plug and bridging the pins.

The coolant gauge temp sensor is located in a flange at the front of the block, the wiring to it is yellow/red I think.

[diagnosis-dub]

Does the car physically overheat?

If the dial is shooting over to the max that quickly and the red light is coming on you would know about it as your car would be seriously overheating.

also if the sender in the expansion tank is knackered it wont make the dial move, it only sets the red light off as a warning to tell you you got low water.

sounds to me like your wiring from the temp sender is earthing out.

[dubchaser]

Thanks all.  I'll have a look at your solutions and let you know.

[dubchaser]

Well, I've sorted the flashing light.  The water was low.  However the needle still goes up to max.  If I turn the ignition on the needle rises even without the car actually running.  Does this make the diagnosis easier?

[rubjonny]

First thing I'd check is the earth lead between the rocker cover and the coil bracket, then try unplugging the water temp sensor.  The sensor is located in the plastic flange at the front of the block, it should have a red/yellow wire going to it.