Ive decided that I need to change the coolant in my fab, as pointed out in an earlier thread my car has a blue/green coolant and Ive been informed that its the wrong spec.... so time for a flush out, does anyone know the best way of doing this or is there a how to?.... I know this should be a relatively easy job, but I just wanna know the best plan of attack, and any tips for not getting any airlocks etc..... was also thinking of replacing header tank as they are so inexpensive...

tips, ideas comments welcome....

fabia 1.2 6v

dont mean to bump my own thread, but has anyone even any idea of the quantity of coolant I need to buy, its just I want to get it on way home from work, the audi garage in town is open to 7 tonight and I dont think they would be able to say whats needed for a 1.2 skoda lol

If it's a one-off job, and you don't have any leaks requiring regular top-ups, you might as well get 5l of Halfords' ready-mix red coolant.

The proper way of doing it is to take the lid off the expansion tank, put the car on ramps / axle stands, take off the undertray and open the drain tap on the bottom nearside of the radiator. Although if you have room and a suitably low and broad container (under-bed storage box etc.), you can take the bottom rad hose off with the car on the ground.

Once the system's empty (give all the hoses a good squeeze / shake), set the heater to 'hot', run through a decent amount of clean water or just put a hose in the top of the expansion tank and leave it running for a few minutes. Then close the drain tap or re-attach the rad hose, put the car back on the ground (if applicable), fit your new expansion tank (if you decide to get one) and fill it up with your new coolant. Leaving the lid off the expansion tank, run the engine at a fast idle with the heater still on 'hot' until the radiator fans have kicked in and switched off again. Then leave the car a little while to cool, top up the coolant and put the expansion tank lid back on. You should be alright after this, but it's probably worth keeping the remainder of the coolant in your car for the next couple of trips, as when I last did mine, the level dropped to about an inch under 'min' the next time I took a proper drive out.

HTH

Haynes says 5.1 litres for cooling system so 2X 1.5 litre bottles of G12 should be all you need. I have always found the Haynes quantities to be over-optimistic and the system usually takes less.

I am basing my tips on my 1.4mpi, I suspect the cooling system is similar (although I am intrigued that Haynes suggests the 1.2 does not have a thermostat). First turn the heater on full, it may be a flap rather than a valve control, but it will do no harm and let you check the coolant is in there later. There should be a feed (top) and a return (bottom) hose on the radiator. On the 1.4mpi the top goes from the thermostat to the radiator, and the bottom goes to a pipe bolted to the bottom of the engine (not a clue where they go on the 1.2). There will probably also be a drain tap on the radiator. Coolant will come out of this quite slowly, my preferred method is to remove the lower hose from the pipe on bottom of the engine. The hose clips can be removed using mole/vice grip pliers. It may be a good idea to have another pair handy so that if the clip needs to be removed from the pliers, then you can tighten the pliers back up once gripped to fully squeeze the clips.The hoses can be difficult to remove once the clips are undone. I either just pull, pull and twist, or if access allows push the hose outwards from the end. An underbed storage plastic drawer would be a good thing to catch the old coolant with (remember coolant will kill kitty if kitty comes and sips it ), but to fit under without removing undertray you'll need to be parked one wheel on a kerb or jacked up a little, or on wheel ramps.

Now the bottom hose is removed, and the coolant is for the most part drained, it's time for the garden hose. One place to start might be to run water through the expansion tank. If the water flows faster than it drains through the tank will overflow though. Send a good amount through there. On the 1.4mpi my next stop would be to remove the temp sender from the thermostat. Using the o ring seal I insert the hose attachment into the hole and let water run for a while to flush the engine block. It may be a good idea to have a cloth handy to hold around the end of the hose to catch any stray water so it doesn't damage the electrics, but if attachment fits in well no water should come out. Let the water flow through for as long as possible. Next I would remove the top hose from the thermostat, and inert the hose attachment into the hose and let water run through the radiator for a long while. Then with the already detached bottom hose on the radiator, I would back flush the radiator by putting the Garden hose in the bottom hose, making sure to direct the top hose downwards such that any water flowing from it cannot reach any electrics. Again would let water run a while.

If there was evidence of gunky stuff in the header tank (that can form when G12 and blue coolant are mixed) I would consider next using a chemical flush. Basically you fill the system with water and add the chemicals to the radiator via the top hose. Connect the hoses back up, fill coolant with water to max, and either drive for 30 miles or run engine at fast idle for about 10 mins (first option probably best and good for environment if you go somewhere). Then once you have done this allow car to cool (careful to not let it freeze as there's no antifreeze in those things) then drain, and I would go back to the previous paragraph again and be a bit more thorough than the first time.

Once you have done, do your hoses back up using the original clips (I damaged two hoses using jubilee clips and will never use them again, even though haynes recommends them. Then you want to fill with your premixed 50:50 coolant slowly. Not entirely sure how it works on the 1.2 but I fill up header tank to max, then fill through the hole for the temp sender and refit it. Run the engine with cap fitted till fan cut in then turns off. Allow to cool and top up if necessary.

thanks you guys... am gonna tackle this tomorrow when Im off work... will call into audi on way home and get the g12 and hopefully the expansion tank if its in stock, ... am wondering if the engine does have a thermostat , is it worth taking off to flush, or could i just flush with water, then fill with water , run engine until warm then drain again, or am I just giving myself more work to do lol

Sounds like a fair idea - it's not freezing (yet) so the anti-freeze component isn't essential, and you won't have any issues with corrosion using clean water for a day.

FWIW, the last time my car was serviced it was drained (although not properly) and filled up with blue coolant, and apart from going a nasty colour after it had all mixed (and again when they only part-drained it a second time and refilled with my own G12) there don't seem to have been any issues...