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General => The garage => Topic started by: dubchaser on 11 April 2005, 14:39

Title: Mk2 GTI 8v temp gauge - goes up to max!
Post by: dubchaser on 11 April 2005, 14:39

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 (http://www.olds-cool-golf.co.uk)

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: Horney on 11 April 2005, 15:06

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

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: Mr Blue on 11 April 2005, 17:18

would of thought its your waterpump.

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

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: dubchaser on 12 April 2005, 11:52

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.

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: Mr Blue on 12 April 2005, 14:22

thermostat?

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: rubjonny on 12 April 2005, 15:10

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.

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: diagnosis-dub on 14 April 2005, 05:03

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.

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: dubchaser on 14 April 2005, 08:03

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

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: dubchaser on 15 April 2005, 08:41

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?

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: rubjonny on 15 April 2005, 11:18

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.

Title: Re: Mk2 GTI 8v temp gauge - goes up to max!
Post by: diagnosis-dub on 15 April 2005, 13:54

Like rubjohnny says checking the earth lead is a good idea.

Also when you find the wire to the temp sender disconnect it and go turn the igniton on, the dial shouldn't move, if it does then you know that the fault is in the wiring to the sender.

The normal test to check that a sender is faulty is to remove the lead and earth it to the engine which makes the dial go fully over to the max. The sender resisits current flow to earth so when they go wrong the dial doesnt normally move at all or very little.

Seeing as your dial is doing this already then it must be the current feed for the sender is earthing out somewhere along the line. trace the wire back from the sender and look for any damage to it.

See if that helps geezer.