hi everyone i bought a matiz se plus the other day and low and behold the heater core was blocked. now for all you matiz owners who are suffering no heat here is a step by step easy way to sort it without the need to go under neath the car.

Disconnect the pipe that connects to the back of expansion/filler tank first before anything.

1) remove the air filter box.
2) remove the distributor cap (2 screws either side) just put to one side with the leads intact.
3) iit is now possible to see the thermostat housing if your not sure just follow the radiator top hose once you see it use a 10mm deep 1/4 drive socket and the right extension bars and of coarse the rachet and undo the two bolts securing the thermostat housing...be patient. also test the thermostat by boiling water and use a pair of long nose pliers or similar and hold under scolding water if it opens its ok.... if it doesnt replace with a new one.
4) now withdraw the thermostat housing still connected to the radiator hose its quite ok.
5) now look where the thermostat housing was and you will see the inlet hose just below, that belongs to the heater core coming from the bulkhead below the thermostat housing and look for a jubilee clip now undo it and prize off the hose.
6) you will need a 6" funnel a hose pipe on stand by and 5 ltrs of brick acid or mortar clean or patio cleaner and a measuring jug.
7) pour about a half mug full of the acid into the plastic jug.
now insert the funnel into the hose.
9) pour the acid into the funnel and let it work for exactly 15 seconds.....DO NOT PANIC! your hoses will be fine.
10) now with your hose running and at the ready force it into the funnel and hold there as you watch all the brown stuff coming out and when clear repeat with the acid again just one more time only ! and insert the hose pipe again and hey presto your sorted....
11) reconnect all hoses, theromostat housing, distributor and air filter then top up with clean water and 50 % anti freeze.

Job Done Took me an hour

hope this helps you all and please dont panic about the acid its not as strong as hydrochloric molar 1 which by the way would strip your skin instantly should you be wary. happy unblocking

Good stuff, plenty of useful info there!

Will add getting to the bottom bolt on the thermostate housing is a complete n utter pig and will eailsy skin your knuckles.

very helpful will try tomorrow, but is there any alternative to the acid's stated i'm short of cash and cant really afford it at the mo. i'm guessing i'd be looking at about a tenner or so for them. bloody recession lol

that cleaner stuff under the sink ending in bang maybe?

dont forget the goggles and rubber gloves.

If you remove the battery, it's possible to use long nose pliers to loosen the clip. You can then get your hand underneath the hydraulics and twist the pipe until it comes off. The rest is as the original post.
-Spikey

got a product called Holts rad flush its a 2 bottle cleaning solution for the radiator, will this do a similar job with the heater matrix?

well just got my car back from the garage after fixing my inlet manifold, they investigated and confirmed that heater matrix is blocked and wanted to charge me £85 to flush it, which i refused obviously, but i just cant get that bottom bolt on the thermostat housing off, i cant even get a socket or spanner near it. its the only thing stopping me getting to the hose. i cant even reach it with the battery out and long nose pliers... any ideas please???

(30-04-2009 05:32 PM)jedidev Wrote:  well just got my car back from the garage after fixing my inlet manifold, they investigated and confirmed that heater matrix is blocked and wanted to charge me £85 to flush it, which i refused obviously, but i just cant get that bottom bolt on the thermostat housing off, i cant even get a socket or spanner near it. its the only thing stopping me getting to the hose. i cant even reach it with the battery out and long nose pliers... any ideas please???

I didn't actually take off the thermostat housing for that very reason (hard to get at). I used long nose pliers to get at the pipe clip on the pipe leading to the matrix, then took out the battery which allowed me the room (not a lot, but enough) to get my hand in and twist the pipe back and forward until it came off. The rest is the reverse.

prevention is better than cure , read all txt
5 min job , engine cold remove header tank cap insert hosepipe turn on , leave for 5 mins , the matrix hasnt been flushed but hey at least theres clean water in there , i do this before my winter coolant change.

10 min job , engine cold remove header tank cap insert hose pipe turn on / run engine for 5 mins , last resort job before you start pulling hoses off .

30 min job , engine cold remove header tank cap and heater matrix top hose loosly and remove thermostat , turn on hose pipe now in heater matrix top hose (back flushing) , also you can drop radiator bottom hose and do the rad too ! , secondly now put hose pipe in header tank and make sure your getting a good flow of water out of matrix top hose , reistall therostat ,
reconnect top hose / radiator hose while water is running .

(important) in all cases you will have to drain the header tank , i use a piece of hose pipe , to allow (neat) antifreeze not premix into your header to the spesific level . best of luck andy

I recently used this technique, used CLR ('Calcium Lime Rust') Cleaner.
WARNING - if you remove the distributor cap to access the thermostat and heater pipes, there is a real risk when trying to force a garden hose pipe to squirt water into the blocked heater system. The distributor got a load of water into the mechanism -the car would start, run rough then stall and not re-start. Removing the cap and wiping the inside only worked temporarily - after two days I had use a hand held heater to dry out the inside of the distributor body.

If you take the dizzy cap off to fix the heater, I would recommend covering it with a plastic bag held on by elastic bands.

Thanks for the guide, I don't suppose anyone would have pictures of the location of these parts would they? I want to give this a go, but never had to do work with the distributor and fans so if anyone has a visual walkthrough or pictures of the location of these parts it would be much appreciated