Heater problem on Renault Clio

I have a problem with a Clio , had it 6 months and never needed to use the heater when I first bought it 5 months ago. Now I do I can't obtain hot air. Thermostat is ok and hot water is traveling in and out of the bottom pipes therefore I have been warned it could be the heater matrix...any ideas? If it is the matrix how hard is it , can you flush it out , if so what is the best way to do it?
Any suggestions?
Thanks[:)]

i too have the same problem with my clio (must be common). Soon i will be attempting to fix the problem. But first we need to make sure that it isn't the matrix, hopfully it is just a blockage or air in the matrix. Drain the coolent and disconnect the hoses for the heater on the engine side. Then get a mate to pour very hot water into the hose until it pours out of the other hose. With the heater blower running you should be able to feel the heat coming out, if not then we are screwed and its a dash off job for a new matrix. The hot water flush should help to free any blockage too. Let us know how you get on if you haven't sorted it already.

can you please tell me in as much detail what i need to do for this problem, like exactly where the pipes are and in wat order to do stuff, ima beginger to the clio engine but not afraid to get stuck in. cheers.
Neil

My brother in law's girlfriends 1992 Clio has just developed the same problem. I was wondering if you could tell me where the thermostat is located and how to check it. Also any details on how to flush out the system would be helpfull
Cheers
Andy

The thermostat is positioned at the front of the engine block by the oil dip-stick. It is undone from a horizontal position un-doing 3 nuts (from memory). The coolant will gush out due to the horizontal opening. I would remove the thermostat before you buy a new one so you can check it against the one you want to buy. There are numerious thermostats. Dont buy before showing the supplier.

Is it wise to take out the thurmostat when doing a water flush as it wont open or summit?

changing matrix is an involved job on clio with energy engine,,run engine up to full heat ,at rear of engine under expansion bottle 2 hoses pass into matrix ,both should be very hot ,,,, if heater still cold ,matrix is shot, VERYcommon on clio; flushing willprobably do nothing,,renewal only answer 40 quid online, you will have to remove entire dash out the car everything out with all wire looms. THERE are 2 main earth connections on side of footwell 1 each side under plastic trim must be disconeted black wires ,.have done a lot of these cars . really not for feint hearted must take pics and notes of procedures,you MUST also flush entire cooling system afterwards and keep 50=50 anti freeze in at ALL times CLIO should have a terrific heater P S energy engine clio will self bleed heater only bleed at radiator good luck================= ZED

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by BOSSMAN</i>

changing matrix is an involved job on clio with energy engine,,run engine up to full heat ,at rear of engine under expansion bottle 2 hoses pass into matrix ,both should be very hot ,,,, if heater still cold ,matrix is shot, VERYcommon on clio; flushing willprobably do nothing,,renewal only answer 40 quid online, you will have to remove entire dash out the car everything out with all wire looms. THERE are 2 main earth connections on side of footwell 1 each side under plastic trim must be disconeted black wires ,.have done a lot of these cars . really not for feint hearted must take pics and notes of procedures,you MUST also flush entire cooling system afterwards and keep 50=50 anti freeze in at ALL times CLIO should have a terrific heater P S energy engine clio will self bleed heater only bleed at radiator good luck================= ZED
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What happens when the Matrixis shot? Does it happen because it is blocked completely?

ALL CLIO MODELS---
VAST majority of heater probs willbe clogged matrix ,the matrix is made up from 8 small bore copper pipeswhich begin and end in a duel header tank at one end of heater unit. Both heater hoses olso go into this plastic header..this little tank is part of end of heater,it is really 2tanks moulded into one down end of heater,1 half has 1heater hose at top whitch feeds water down one side 8 copper pipe holes are also don this side so water rushes into these small pipes,... the other hose is fed into the other half with its 8 pipes .so the water comes in one half ,goes through copper tubes then returns to engine out other half ,BUT the 2tanks olso bleed water from one to the other,this is why both hoses will be hot but heater cold the small bore pipes are clogged always bottom one first corrosion just works its way up header tank clogging each pipe as it rises-----------
THISis caused by owner neglect of the entire cooling system,WE do alot of these cars ,you MUST have 50-50 antifreeze in at ALLtimes
once ayear completely flush entire system ,take RADiator out, stat out ,drain plugs out engine,then garden hose time tillclear water runs.Most clio engines use RENIX SP or MP fuel injection.,on cylinder head there is coolant sensor which has big correcting factor on fuelling,severe corrosion of this sensor will give false managment input leading to drivabillity problems. PROPER maintenance is vital
CLIO models should have terrific heater'' to change matrix is NOT a beginners job on these cars

Thanks for your advice it looks like a no hoper.
Due to the size of the job I doubt that it would be touched for a while. But before that is there anyway a flushing agent could have any effect on the matrix if it was passed via one of the two pipes that go into it ,or because it is corroded (which I believe it is) there wouldnt be a chance of the coolant passing through these pipes.
Is there a chance...give me some hope!!!

WE have tried most comercial flushing agents, we even tried caustic soda on a half chocked heater,but we gave up, wejust got some out,even high pressure water down each heater hose near to bursting,gave little result ,, YOU MUST NOT PUT CAUSTIC SODA INTO YOUR SYSTEM,,VERY CORROSIVE,,, even had heater in hand in workshop thumping small pipes with spanner ,would take ages to clean it this way.THIS is a problem with clio,but dont be put off ,front wheel bearings can growl at you ,other small niggles but this model 91-98
are very good when properly set up ,my wife has smashing 96 RT 1390cc
in silver a wee cracker,,,I WOULD OFFER NO CHANCE HERE if heater is cold , check flaps but usually no probs here ,unless someone has been tinkering.,there is also alot of work to do in bonnet area around bottom of windscreen must be stripped out ,computer out, wipers out,blower out to get to 2 bolts that secure full heater unit,have known owners take them out .but cant get it all back together again.
even good HAYNES MANUAL WILL OFFER novice little help, it is fully covered in this book, get a very good DIY mate,other wise its a garage and can be pricey------------so sorry..i have done job 6 hours
saturday ,but set aside a weekend----------------------- ZED