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HOW TO : Flush cooling system and change thermostat.

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HOW TO : Flush cooling system and change thermostat.

Well folks, having found this the other day :



I decided to not only change the pipe but flush the system, renew coolant and change the thermostat. Thought I'd do it as a How To to pay back for all the information I've had, so here we go.

You will need :

1 x Ratchet
1 x 10mm long socket, if you don't have a long socket a small extension bar's needed
1 x medium to large pair pliers / mole grips
Flat or X head screwdriver - for jubilee clips
1 5/8" jubilee clips for larger hoses
Garden hose (preferably with trigger gun)
Patience (lots of  :lol: ) for reasons that'll become obvious
Thermostat & O ring (mine cost just under ú6 the pair @ EuroCarParts)
Antifreeze, minimum 2ltrs
Waterproof footware  :D
Big piece of cardboard to lie on
Coffee
Fags (optional)

Make sure the car has been stood a while before starting, hot water n all that  :wink:

Remove cap on expansion tank

To start I removed the elbow joint underneath the water pump, this is located at the bottom of the block on the left looking from above. Easiest way to locate is follow the bottom hose off the radiator, it connects to the elbow.

Working from above undo the two 10mm bolts and ease the elbow away.

Water will pour out so beware, you have been warned. Chances are the thermostat and O ring will remain in place like this :

Again working from above use a screwdriver to remove the thermostat (the O ring will come out as well), there's a thin bar you can slot it through and lever against water pump, water hazard again  :roll:

Now undo the large pipe on the top of the radiator, this is where patience is required if you're unlucky. I didn't have jubilee clips but spring loaded clips which require two pieces pulling together then you have to slide it away. Trust me, easier said than done  :banghead: The parentage of the inventor of them was questioned several times  :lol:
Once you've got the top hose off flush radiator until clear water runs. Water will come out of elbow joint so direct water away from feet   :D
Once done you're ready to flush heater matrix
You need to undo the clip located top right nr rocker cover and slide rubber pipe off metal pipe. Make sure heater control on dash all the way over to the right (HOT). Once it's off flush through until clean water :

Water will come out from where thermostat was.
Then flush through from expansion tank until clean water

Again, water will come from where thermostat was.
I then replaced the split pipe :lol:
I then removed elbow joint from bottom pipe.
Get your cardboard to lie on, then under the front you go. Locate O ring on elbow joint then sit thermostat on that (re-fit the correct way round see earlier pic), locate it back on the bottom of water pump and tighten the 10mm bolts. Nearly done :D  
Now re-attach all your hoses replacing the stupid spring clips with jubilees  :D

I then added 2ltr of water + 2ltr anti-freeze and started it up, don't replace expansion tank cap yet. Watch as water runs back through into tank. After a couple of minutes I added another litre of water and put cap on expansion tank. Leave to run until upto temperature (fan kicks in). I kept checking bottom pipe until it started warming up (it takes a while) so I knew the thermastat was working ok. Also put me big piece of cardboard under the car to check for leaks as drive was wet, came out bone dry :D Now turn engine off and slowly take cap off expansion tank, take care HOT water, top up to max line. Job done, time for tea  :lol:
Took just under 3hrs 8O Would've been half that but for those silly spring clips :banghead: :banghead:

Thanks to Pedders and Jelly for tips and advice before I started this  :wink:

Hope this helps others

Chris

Finally, drove to work this morning let the car stand for a couple of hours then checked water level. Added another pint of water to bring it up to correct level  :mrgreen:

I no longer haveáthe Mk1!! I now whizz round in a Blacká1990 3dr Mk2 GTi 8v but the roof doesn't fold back when the sun shines :o

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top job!!!

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Cheers mate, only fair to share what I learned (with the help of others  :wink: )  :mrgreen:

I no longer haveáthe Mk1!! I now whizz round in a Blacká1990 3dr Mk2 GTi 8v but the roof doesn't fold back when the sun shines :o

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And done with such eaze!!! Only wish it went that well for me…   ; )

Mk1 Cab:
Mk6 GT TDi

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Good guide. I did a flush last month, following the basic Haynes guide. Didn't get any crud washing out, was quite disappointed! I agree, only tricky bit was that bloomin' radiator hose clip! Needed 2 pairs of hands to get the hose back on.

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hey. thosse clips suck!! do you know part number for that hose you replaced?

cheers

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Just did this myself - talk about rubbish washing out - it was like the muddy water from a canal!

Also found it didn't have a thermostat - all fitted now thanks to guide - so far so good!

Going to change the bottom pipe to vag part - I think current is just a rubber pipe bent to fit, has left a slight weep at join with radiator.

Also ran it after first wash through with holts speed flush - was dirty on second flush too, no where near as bad though.

What are those clips all about?? Easy to remove - impossible to put back on!

Anyway good guide pal - cheers!

Sam

86 Cabby 1.6 auto - Super cool daily retro various

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nice matey wish it was that easy for me im at the end of my tether, my 88 cab wont stop over heating, flushed system through new water pump new thermostat re filled sytem with new anti freeze and temp gauge still goes over to max mark within about 8 mins and bottom hose is only just warm by this point so rad not hot so then the fan wont kick in what do i have to do to stop it over heating, cant drive it like this. please some one put me out of my misery.

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Maybe the new thermostat is duff (can never be ruled out!). Take it out altogether for the summer, at least then you shouldn't overheat!  :lol: Probably not a good idea long term though.

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thanks mate
just what I had in mind for sat morning.
thermo not working so fan not coming on.
Plus system never been flushed.
ever

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Good effort Chris.

I flushed mine in Janary, not the best time I know!!! I didn't do the heater though cause I thought it all flowed through naturally!! Learnt something today!

Dan

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yea sound mate, thanks.

All this needs doing soon.

I jsut want it to be a little nicer weather.

Well it didnt stop me getting rained on for the past 3 days.

aha.

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Diesel-dubber said

only tricky bit was that bloomin' radiator hose clip! Needed 2 pairs of hands to get the hose back on.

a pack of nice shiny jubilee clips! looks fresh and one hell of alot easier!

1983 VW Golf 1.8 GTi
2008 VW Golf GT TDI 170

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Now then fellas,

A little tip, try using a set of water pump pliers on those horrible clips (think the devil drives a car put together with these things)

It is allot easier, you can adjust the pliers width and grab both ends of the clips and squeeze then it shuffles of with some wiggleing from your self.

When i had my clio RSI it had them and when i flushed that it was easier with these !!

Regards

Will be carrying out my flush ready for the winter coming !!

1990 Mk1 Clipper Cabriolet

2005 Megane 1.6 VVT

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pliers for rad clips

These are the babies you need for those clips, bought some myself and it has made life so simple (don't need em everyday but when you do!!) there is a rachet so can be used one handed.

Hope the link works.

http://cgi.ebay.co.uk/2-Pc-Spring-Hose-Clamp-Clip-Removal-Fitting-Tool-Pliers-/280703170232?pt=UK_Hand_Tools_Equipment&hash=item415b3676b8

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Cheers for the thread mate, well written and good clear images :)

As for them clips, yeah without the right kit their a pain in the rear!! I'm switching mine for o-clips too  hehh :)

Thanks again for the thread!

I'm so flipping lonely, it's killing me lol at least I can laugh about it!!

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Hi my thermostat came with a card gasket do I use that also?

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Hi I got my new thermostat fitted. I was gutted that the car still has the same overheating problem and the new thermostat has not made a difference. Can anyone please tell me where to go from here. Cheers

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i would start a separate thread you will get more answers and you can give us more info :)

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Thanks will do
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