This guide is based on my 1999 mk1 Punto's 1.2L 8v engine. The method is pretty much the same for all versions of the FIRE engine system but some parts may vary in layout, if things don’t match up to my description then ask in the forum section or use your prior knowledge, whichever suits. This guide has been split up into as many small sections as possible so that referencing each part of the job is as easy as possible :)

Foreword (nearly)
After a period of time (about 2 or 3 years) your antifreeze could do with being removed and replaced with a new, fresh mix of antifreeze. If tap water or other impurities have been allowed to enter the coolant system (such as oil via a head gasket failure) then the surfaces of the pipes and metal surfaces can become lined with a layer of thick gunk. In my case this was from a mixture of tap water being put in by the previous owner and the coolant system having NEVER been flushed in the 9 years the car had been running!

There are a variety of radiator system flushing liquids such as Holt's radflush, feel free to use those in conjunction with this guide (I will comment on this later in the guide for those who want to use it).

*Note* If you are using radflush then you will need to follow this guide a second time after running the engine with the radflush in after the first clean out. As such you would need double the amount of coolant for this method.

Tools required

  • 10mm socket and associated socket wrench or a 10mm spanner
  • Pliers and/or wire cutters
  • Screwdriver
  • Garden hose pipe and associated water supply and whatever fitments your system happens to need or is convenient for use
  • A container to catch purged fluids in (this needs to be as large as you can get under), I used a 5L screen wash container with the lid firmly attached and the side cut off.
  • A blunt knife (such as an old butter knife)
  • Some wet and dry material
  • Disposable cloth or clean work rag
  • Work clothes and shoes you don’t mind getting wet and/or dirty
  • New, cheap toothbrush (possibly)

Spare parts required

  • Jubilee hose pipes
  • 2x 35-50mm (so long as it goes down to 35mm its fine)
    • Plus 1 extra if removing the bottom pipe
    • Plus 1 extra if replacing the thermostat housing or removing the pipe from the housing for cleaning
  • New thermostat gasket or liquid gasket compound (I used a liquid gasket; it's been fine so far)
  • Aew o-ring if you're taking the metal pipe off as well, please don't ask me how this is done, I haven't tried this but I happen to know there is an o-ring that will need replacing in there!
  • Approximately 5 litres of ethylene glycol based antifreeze mixed in a one to one ratio with pure distilled water (or 5L of ready for use ethylene glycol antifreeze made up from the same mixture) per flush

Other applicable guides
The only other guides that may be of help are those that instruct on how to bleed the radiator system in more detail. I have included a basic description but these may also be of use:
How to: bleed a mk1 Punto Cooling System - by Dave
Bleeding the cooling system on a mk1 punto. - by vtec

Things to expect

  • Get wet
  • Get dirty
  • Get annoyed at the original pipe clips

There are a number of things to be aware of whilst carrying out this job. The most obvious one is injury through coming into contact with hot engine coolant. Please be careful in making sure the system is cold before pulling it to pieces or trying to remove the pressure cap on the radiator bottle (it will shoot out due to being under pressure if it is hot enough!). Also you need to dispose of the old coolant and any fluids generated carefully. They must not be disposed of in a method that allows them to enter a water supply and not just left on the ground. Anti-freeze attracts the attention of animals and small children and is lethal if ingested. Please read the information on the back of the bottle or search on the internet for more information (or come and ask on here).

Finally, a helpful hint with filling and bleeding the radiator
I found it was easier to park the car with the nose pointing up a slight incline (my driveway has a slope of about 20 degrees) as this brings the heater matrix bleed point closer to level with the filler cap point!