Mk4 Golf gti overheating, please help !

[mk4_gti]

Hi guys,

I bought my gti on saturday and has been running fine until today, was driving home from uni and on the way the temperature started to rise slowly, then quickly overheated and temp light came on. i pulled over and turned it off and cooled it down a bit then checked oil (not much oil but hard to accurately tell as car was on just before), coolant level is fine but car is definitely over heating after 5-10 mins of it being off i opened bonnet and could feel the heat on my face as i opened the bonnet. turned it on again and the temp level was one bar above 90 degrees and i drove it home very slowly not taking it above 1500 rpm and it stayed at that temp until i got home and would go up if i revved it higher.

Could someone please tell me what could be wrong, if there is a mechanic who can come to my house and check it or someone with vagcom in sydney close to canterbury area ???

[Swainey32]

coolant temperature sensor, if its the original black plug, they fail heaps and the fan doesn't come on for coolant.
$40 max for this part (new green one), literally pull it out then plug new one in.
I'd try this first, very common problem.

[Swainey32]

How to change
http://uk-mkivs.net/forums/t/183811.aspx

[geoff_gti]

Were the fans coming on? I'd be worried it's the water pump!

[Swainey32]

http://www.ebay.co.uk/sch/sis.html?_...20PASSAT%20etc

[mk4_gti]

coolant temperature sensor, if its the original black plug, they fail heaps and the fan doesn't come on for coolant.
$40 max for this part (new green one), literally pull it out then plug new one in.
I'd try this first, very common problem.

Thanks will try that first

[mk4_gti]

Were the fans coming on? I'd be worried it's the water pump!

Fans dont come on until you turn on air con I hope it's not he water pump! Lol

[Swainey32]

certainly sounds like a temp sensor then, if its not turning the fan on then as far as the engine management is concerned its thinking the coolant is a reasonable temperature

[mk4_gti]

certainly sounds like a temp sensor then, if its not turning the fan on then as far as the engine management is concerned its thinking the coolant is a reasonable temperature

hey yeah thanks i changed it today and seems to be running fine now hopefully that was it =)

[h100vw]

The temp sensor runs the temp gauge and the ECU. The fan switch is screwed into the side of the radiator by the battery/starter motor.

My money is on the water pump at the moment.

Get it to temp, then squeeze the top hose hard and rev the engine, use the cable pulley on the throttle body. If the pump is OK the pipe will swell up in your hand. If the pump has gone it won't swell up.

Gavin