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Coolant Drain And Flush?

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Hi, first post here!

Got a 2007 SportKa, which ive had for a year now, and i really enjoy it. I dont use it as much as id like to, due to living away from it at Uni, but now im home for summer its all go!

Just had its MOT done, and i'm about to do a quick service. I noticed a while back the heating was always hot when it was up to temp, so i replaced the HCV with a cheap one from eBay (don't know how long it'll last), but that should sort it.

However, before replacing the HCV it had a slow leak so i topped it up regularly with just water, so the coolant will be fairly diluted. Also the old HCV plastic crumbled when removing it, and i tried my best to get all the plastic bits out the hose, there are probably bits floating around.

That means i'd like to drain and flush the whole system and fill up with 50/50 antifreeze. How would i go about it?

Do i need to remove the thermostat? Because im assuming it'll need a new gasket or o-ring, and i dont really want to go getting that if i dont have to. Can i just remove the bottom hose at the radiator and drain everything out, then use the garden hose to flush out the radiator and engine (separately)?

When its all clear, just reconnect all the pipes, then slowly fill up with coolant, start the engine and squeeze all the pipes to get rid of air, then top up accordingly? Any help would be great, thanks!

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for this job you will need:

An array of screwdrivers, socket set (or adjustable wrench if necessary), a large container (bucket should do nicely), coolant flush, water, and lots of empty containers. (oh, and your nicy shiny new coolant)

You basically jack the front end up of the car, you will then see at the bottom of the radiator either a screw / nut or valve that will allow you to drain the coolant, put the bucket or such under this, release the screw / bolt / what have you and drain the system. Then just pour a bottle of water into the coolant tank and that should help rinse a little more out the system.

Now, reseat the plug / screw / bolt.

Open the cap at the top of the radiator, or if you dont have one, pour the flush into the expansion tank and leave for a few moments to settle. run the engine, heaters on full wack, full heat for about ten minutes then stop the engine. let it cool for a few minutes as the fluid should be hot, so you dont want to scald yourself.

Now open and drain the radiator again.then when its empty, refit the plug.

My personal opinion here is that you now fill the entire system up with water (to the max mark on the tank) and run the engine again, ten minutes, full heat etc.

Now, l;eave it to sit for a few minutes, and if you havent already, empty the contents of the bucket into any containers you have (a good option for this is to use old 5L screenwash bottles).

Now drain the engine, make up the 50/50 mix of the OAT Red antifreeze or if its ready made, just fill the system up. Dispose of the fluid appropriately (your local council recycling centre probably would accept them) and your good to go.

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Well thats it done i think. Only thing is, that there didnt seem to be a huge amount of fluid draining, maybe a few litres? Its supposed to hold just over 5 litres, but after draining it only took a few litres of coolant up to the maximum line. I ran the engine for more than 10 mins, squeezing the pipes to get rid of air, and it needed topped up a little, but not much.

I dont think it was getting hot enough, as the front fan didnt come on.

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you might have had an obstruction or airlock causing it not to drain fully. Best thing to do is checkl the coolant a few times over the next few weeks, if the colour is as strong as it was when it went in great - if not it might need doing again.

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  • 7 years later...

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