Author Topic: HOW TO: Bleed & check your coolant system for faults  (Read 5854 times)

Offline rubjonny

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HOW TO: Bleed & check your coolant system for faults
« on: 25 January 2006, 09:13 »
Notes:
The system takes just over 5 litrs when empty, there will always be some coolant left in the block unless you remove the thermostat though :)
Use G12+ coolant from VW, or G12 from http://www.vwspares.co.uk
Use at least 40% coolant, I normally use a 50:50 mix in my GTI 8v and it runs nice & cool :)

Bleeding the system after refilling:
Run the engine from cold with the cap off and rev it to 2k now and again.  While you are doing this squeeze all the pipes you can get your hands on, and keep the coolant level topped up.  It will eventually start to boil over, at this point turn the engine off.  Once its settled down top it up to the max mark and you should be good to go!

Checking the operation of the system:
Check the lower rad pipe is stone cold until the temp gauge reaches the half way point, if it gets lukewarm straight away then the thermostat is stuck open or missing, if it stays cold then it is stuck shut.
Check the fan kicks in when the gauge gets near 3/4, if not disconnect the plug from the radiator sender in the bottom, passenger side of the rad & bridge the pins.  If the fan spins then the temp sender is broken, if not jump the fan direct from the battery, if it still dont spin then the fan is knackered :)
« Last Edit: 25 January 2006, 09:17 by rubjonny »
Hello my name is John and I'm a dub addict.