Wednesday, 18 July 2012

Radiator Leak Repair

Since first getting the car on the road there has been a very slight leak from the radiator bleed bolt.  I'd tried tightening it up a number of times, including using PTFE tape on the threads, but it always continued to leak.

I tried one more time, but unfortunately this time I overtightened the bolt and stripped the thread in the radiator - turns out the tread is just tapped into the aluminium so is very weak. My solution was to re-tap the  hole to a larger size (M10 x 1.5mm thread) and use a spare cap head bolt of the same thread that I just happened to have spare.

Once the bleed bolt was fixed I could get back to investigating the leak.  Upon closer inspection it was not the bolt that was leaking at, but a pin hole in the weld around it!  With the engine running drops of coolant would slowly form.  I decided to leave this for a while as the coolant was only coming out very slowly.

Many miles later I got a coolant overheat warning from the Webcon ECU.  Turns out there was air in the top of the radiator and the coolant was no longer flowing properly.  The cause was air being sucked back in through this tiny pin hole each time the engine cooled down.  Something had to be done to fix this. I took the front of the car apart and removed the radiator.  This was when I discovered that the pin hole had turned into a crack, probably about 10mm long.  The body of the radiator was starting to split.

I quickly took the radiator to the friendly local welders who re-made the weld over the area where the crack was.

I'm happy to report that after a few hundred miles of use there is no longer a leak in the radiator.  This gives me added confidence for longer runs, particularly with another trip to northern France booked for later in the year.

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