Phew! Is it me or is it hot in here?

As reported in the introduction BART had a temperature which caused us to abandon our first test drive.  With the engine now running well I started to investigate...driving around the local roads ~30 to 40mph the radiator fan would kick in after about 5 miles.  The temperature would then keep rising slowly getting into the danger zone on the temp. gauge.

The first thing I tried was to bleed the system correctly, this involves pointing the nose of the car down a bit in relation to the engine and opening up the bleed nipple on the front mounted radiator.  Coolant should flow out of the bleed nipple when all the air had been bled.  With this done you need to set the heater valve inside the car to open, top up the expansion tank if needed in the engine bay and run the car up to temperature with the expansion cap off to bleed out any remains air.

I did this and managed to bleed some air from the system but it didn't cure the overheating, there was some improvement but it still wasn't right.  Having experienced a similar issue with my 1500 X19 I checked if the whole of the radiator was getting hot...lo and behold only the top third was hot, the rest was cold to the touch.

There was nothing else for it; I had to drop the radiator and try to flush it out or at worst replace it.  It's quite easy to drop the radiator out on an X19 but its a messy job!  With the radiator out I set about flushing it forward and backwards with a hose pipe and in-between picking it up and sloshing the water around inside, the amount of rust and debris that came out was quite an eye opener!  This is just a sample of the hard lumps that came out as well as rust:

I also mixed up 500ml of caustic soda and sloshed that around inside the radiator, this removed additional crud that flushing alone didn't touch.  As an added precaution I flushed the long transfer pipes that run underneath the car from the engine to the radiator, a surprising amount of debris came out.  With the rad back in the car and bled correctly as before the whole of it now got hot to the touch and the temperature needle stayed just below half way throughout my follow up test drive...result!