Coolant leak at coolant level sensor / header tank

[stevenm]

Recently noticed I was slowly losing coolant

On investigation there was coolant in the recess on the header tank where the level sensor is

As the seal in the header tank cap looked a bit knackered replaced that first

Coolant still collecting in recess on the header tank

Fittted new seal to coolant level sensor problem solved 400 miles later problem returned on holiday AA called tightened up sensor problem solved

100 miles later problem returned again removed sensor used a few turns of PTFE tape tightened up as much as I dared - wait - week later leaking again

Presumeably next stage is to replace header tank as it may be cracked or porous visually I cant see anything wrong

Anyone else had this problem before

[Ian Hulley]

It's a common problem .... I bought a new header tank (these crack from the dalek cap down to the sensor hole but this only shows up when hot) and a new sensor (these crack between the hex head and the threaded part) and fitted the sensor using high temperature silicone sealant. Not leaked since ... touching wood.

Ian.

[tonytech]

Not had your problem, but I bought a new JK header tank that leaked from the seam.
VW ones a bit more expensive but much better quality.

Also, do you have a blue tank cap? there are some poor quality black ones around.
T

[stevenm]

Thanks guy

Yes it is a proper blue header tank cap

Looks like its off to VW for a new sensor and headertank