97 Heater Matrix - bernie
Hello chaps,I have just found your excellent and informative site while searching the web for an answer to my problem.

I have coolant leaking from somewhere under the dash and it is obvious from the smell and misting windscreen etc,that the matrix is leaking.My question is,how big a job is it to replace?

I am competant but if this is a " dash out job "I wont bother.

The car is a Laguna RXE 1997.

Oh yes,I dont know if it is connected,but I think the A/C has lost it's gas as it will not cool even though the compressor,etc is fine.

Any help would be appreciated !

slt to include drop down menu thingy

Edited by Pugugly {P} on 22/12/2007 at 21:45

Laguna Heater Matrix - Dynamic Dave
Hello chaps,I have just found your excellent and informative site while
searching the web for an answer to my problem.
I have coolant leaking from somewhere under the dash and it
is obvious from the smell and misting windscreen etc,that the matrix
is leaking.My question is,how big a job is it to replace?

Have you tried Radweld? IMHO a heck of a lot cheaper if it works. Saved me once having to change a core plug on the engine. 3 yrs later still no leak.
Laguna Heater Matrix - M.M

Your fears are justified, on an air-con Laguna this is a dash out job. Even if the air-con was working you need someone able to re-gas it because part of the system comes out to do the matrix.

It would be a terrible job and at dealer rates....a guess perhaps 10hrs at £50/hr!!!

DD is right, try the strongest Radweld type gunge you can find....then sell it!

I look after an Espace with exactly the same problems as your Laguna, leaking matrix to the carpet and failed air-con. The owner was so horrified by the complexity/cost of the job I was asked to go for "Radweld" and they would ponder the final solution.

Don't get me going about Renault costs!

David W
Laguna Heater Matrix - Dave N
Hey Dave W, you got out of the Espace heater matrix then?

I don't know what it is with French cars, and Renauts in particular, but virtually every job seems to be major hassle. I did a condenser on a new shape Espace the other day, and wished I'd never taken it on. Front bumper out, upper x member, headlamps, radiator, fans, bonnet ('cos there's nothing to prop it up on), then tons of hassle filling up the coolant and getting it bled. Compare it to 0.4 hours for a mondeo condenser!
Laguna Heater Matrix - Andrew Moorey (Tune-Up)
Oh don't take on so! I was just going to ask you to replace my condenser and fix the face level vents!:-)
Laguna Heater Matrix - Emerson Fittipaldi
Yes I can confirm that it is your heater matrix. I have recently had mine done (under warranty fortunately). Mine is a 1998 Laguna 1.8 Sport. I had a fishy smell coming from the heater vents, then when driving down the motorway I turned on my heater early one morning and the car filled with steam. The garage that did mine took them all day, as mine has air con too as it's a 'dash out' job. It probably won't last long and you should check your expansion tank regularly, as mine was dry after a couple of days after filling it up! It IS an expensive job, so get rid quick, or try and tackle the big job yourself. Good luck.
Laguna Heater Matrix - bernie
Thanks for your replies.Emerson,your description of the fault is exactly what I am suffering.I have since bunged in some Radweld and for good measure some BarsLeaks.I don't know if mixing the two is advisable but I am desparate to fix this so I can gat rid,although this then raises issues of a moral nature.

So far I seem to be having limited success.

On another point,what if any are the medical implications of breathing in these antifreeze vapours?I do know that glycol is poisonous and the glass in the car is coated with an oiley residue so we (my wife mainly)must be breathing the stuff in.

Would American citizens with their " sue everybody " nature put up with this manufacturing fault?,for surely that is what this is.

It's a shame really because the car is generally in good nick and runs well,apart from a slightly "knocky" rear suspension fault,but thats another tale.
Laguna Heater Matrix - lezebre
Medical implications? No, I don't think so. Glycol isn't particularly volatile; that's why it makes a much better anti-freeze than the alcohol which used to be specified. So although it's smelly, the concentration in the cabin air won't be significant. Ok, it's poisonous if you drink it - and much more so for your cat with its relatively primitive digestive system - but in this context, no worries.
Laguna Heater Matrix - Dave N
If you go to the states, you will see the typical warning 'The state of ------- has determined that antifreeze can cause cancer etc.' But then again, so does breathing air!
Laguna Heater Matrix - Emerson Fittipaldi
Hey Bernie, Mine too has a knocking rear suspension? Weird hey? They must be twins, made next to each other (on a Friday afternoon) at the Renault factory! Just before I go, is your engine noisy? Mine has developed very noisy tappets since I bought it in March. However this is booked in next Friday to have the knocking sorted, on both suspension and steering, and to be re-shimmed! If that don't sort it, it's a bottle of Motor-Up and a quick sale! And yes the answer to your question about whether antifreeze is bad for you...yes it sure is. I have a 1 year old boy, and did'nt want to subject him to the vapours coming from it. I thing the general consensus is to flush the system every 2 years (or earlier) with new water and antifreeze.
Laguna Heater Matrix - bernie
Emmerson,the knocking rear suspension on my car is almost certain to be those big diameter bushes on the end of the suspension beam thingy.The local garage quoted me about £500 to do the job so I will put up with the knocking for a while.

The engine on mine is very smooth up to about 3000 rpm but gets a bit course after that butI put this down to being an old design.

Since putting the gunge in my cooling system the leak seems to have stopped,but the interior still mists up a bit if the heater is put on hot.Smells a bit as well.

I noticed from your profile that you like flying.Is that flying as in PPL ?I have a PPL which is not current at the moment but used to fly a Piper PA28 and did a bit of aero's in a Slingsby Firefly at Sherburn Aeroclub.

Laguna Heater Matrix - brucel

A pal of mine managed a replacement heater matrix on my Laguna RT sport, BUT is wasn't the air con version. He indicated to me if it was he wouldn't have tried it. It took about 2hrs. The part cost about £60 with my local Unipart Garage quoting £250 all in.

We didn't need to take out the whole dash, just a small cover to the left of the central consol, in the passenger side foot well.

I like the Laguna, but all the 2nd hand cons expressed in HJ's guide has surfaced in my Laguna. I won't get another!


Laguna Heater Matrix - kiwi
Guys, I have a problem which may be similar but is not yet leaking into the car. Under acceleration, there is a gurgling sound (like flowing water) coming from the dash on the passengers side. Renault think that water has got into the heating system and are quoting £700 to fix it (dash out job I presume) Any ideas on how this could be fixed? It's a 1996 baccara 3.0V6 with air con. Any help would be appreciated as I am trying to sell it!
Laguna Heater Matrix - M.M

In my experience this is usually nothing to do with water in the heater ducts.

I have a Megane in today with exactly the same noise...it is due to the customer allowing the coolant water level to drop below the minimum and then air has become trapped in the system. As you rev the car there is a "rushing" sound from the area of the heater inside the car.

Simply properly re-filling and bleeding will cure this. Yours should be the same.

It is true if your heater *did* have to come out the dash would be removed at enormous cost.....mainly because you have air-con.

Get someone who understands to fill/bleed your system and see what happens.

Laguna Heater Matrix - kiwi
Middle man - you are da man!

Sounds very likely that this is the problem. It's the wife's car and I did have to top up the water level and I am pretty sure that this started at abot the same time.

Any quick tips on how to bleed it - otherwise I am sure that Renault can figure out how to bleed the system.

Thanks for your help.
Laguna Heater Matrix - M.M

The bleed nipple locations can be different due to year/model variants so I just say make sure you find them on your individual car. It is second nature to scan over all the usual locations when you see many different cars. You are looking for bleed screws at high points on the coolant system. Sometimes at the top of the radiator, on hoses adj the thermostat and on the heater hoses.

Again depending on the system (and how the car is parked at the time) you may have to fashion a "header tank" to get enough head of water for positive bleeding from each point. With this Megane that I've finished it was just OK when the coolant expansion tank was filled to the very top, once the bleed points were tightened I removed the excess coolant.

In cases of a diffucult system I've found you may need to disconnect one heater hose and positively fill the heater with coolant first to ensure all the air is out of that section.

Once the system is filled, bled and back to normal level don't open a bleed point again "just to see" because it may suck air back and start the whole cycle again.

Good luck.

Laguna Heater Matrix - kiwi

Good news!

I located the bleed nipple just by the rad as you suggested. I undid the screw a few turns until the fluid was coming out and then ran the engine for a bit - got the wife to rev it as well which increased the pressure and seemed to let out some air as well. The noise has pretty much gone, but there is still some air inside when the car starts moving for the frist time then it stops - a few more goes should sort it out. Do you think that it is best to bleed the air out under low or high revs?

Thanks for your help.
Laguna Heater Matrix - M.M

Glad it looks as if you're getting somewhere with this air problem. Actually there is a danger that bleeding with the engine running will allow the cooling system to pull air in due to the circulation effect.

For a 100% job it is likely you will need to form some sort of extra header tank** to drive out the "difficult" remaining air.

You should then fill the system and bleed without the engine running before closing the bleed points.

Then start the engine and run it at a fast idle (with the open header tank on) until the thermostat opens and you should see a load of air burp into the header tank. Continue running until the bubbles cease in the header tank.

Next stop the engine and carefully check each bleed point for air again (this coolant will now be scalding!).

Allow system to cool and then add/remove coolant to get the correct level.

Check the following day when absolutely cold to get a final coolant level.

**If the requirement for a header tank is marginal sometimes parking the car on a slope with the coolant filler on the uphill side is sufficient



Have You Fixed It ?????? - bernie
Here Goes,

My first post to this board was advice on my leaking Heater Matrix on my Renault Laguna.
Apparently a well know problem.General opinion was to bung in the radweld and get rid.
I did get a few quotes from Renault garages and the prices ranged from £600 to £900
with the same old story of dash out ,door off.

I was just about to give in when I rang what was once a franchised Renault garage but was now a
Citroen dealer.

They could do the job and they had developed a "professional bodge" that meant they could do the job
for about £200 in a day.This involved cutting open the heater box to remove the matrix and
then sealing it back together.

Job done in a day as promised.

I just wonder if this is what would have happened at the other garages only they charge
the full amount.
Have You Fixed It ?????? - Ben79
A Citroen dealer doing a professional bodge job repair? No way.

Not that my car has bluetak stopping a speaker cover rattling or anything...

Have You Fixed It ?????? - bernie
Just to avoid confusion,I should have said REPLACED the heater matrix and sealed up the heater box containing the matrix !
Have You Fixed It ?????? - Ian D
My brother had a blocked matrix on his 98 Scenic DTi (diesel with aircon). The local Renault dealers wanted around £550 to £600 to do the job, a local Renault specialist did it for £260!! No problems and not involving cutting up the heater box. So the morale is do what your garage did or find an good independent specialist... Incidentally the specialist quoted £320, but when he picked the car up they said they did it quicker than expected (having done a few recently) and only charged £260!!! spooky...
Have You Fixed It ?????? - zoom
I am interseted in getting my Renault Laguna blocked matrix replaced, can you give me the contact of Renault Specialist. Ta
Have You Fixed It ?????? - zoom

I don't fancy paying out £600 fo a new heater matrix for a Laguna. Mine does not leak, but is well blocked.
Can you give me the name and number of Citroen dealer who does the "professional bodge".

Have You Fixed It ?????? - Dynamic Dave

Unfortunately bernie (the guy you're replying to about the bodge) hasn't visited this forum since Sat 18 Oct 2003
Laguna Heater Matrix - Arfur
I drained, flushed and refilled the cooling system on a 95 laguna when I had one a few years ago. Stained the area in front of my garage red for about a month, very rusty. Anyway on a positive note when I did the job I had no idea that I might need to bleed the cooling system after the job. I didn't and it didn't seem to cause any problems. I did however keep a close eye on the level for a couple of days afterwards which resulted in a couple of top ups. Presumably this was the air being driven out of the system.
Laguna Heater Matrix - dodger
Hi Bernie

I have a laguna 2.0 RXE 1995 and it has the same problem. Used Radweld and it seems to have held for the last couple of years, although it has started again recently. Look at the BACK ROOM on the recall notices, they talk about this problem there. Could be worth checking out the recall notices - you might get it under warranty...

Have you had any problems with your remote alarm? Because that goes next...
Laguna Heater Matrix - stuartbr
I've just tackled this job on the laguna 2.0 RXE with aircon. Initially (and according to most web sites) I though it would be a dash out job. I managed to do it in 3 hours & by removing less than 10 screws.

Basically the blower unit & aircon radiator stops you from removing the old unit under the passenger dash.

I cut a hole in the blower unit cover which allowed sufficient space to replace the heater matrix. Sounds scary, but reqally wasn't a problem.

Start by first remove the cubby hole (not essential, but helps), the 2 screws holding the heater matrix in place, and the bolt holding the pipes onto the heater matrix.

Then drill a small whole in the bottom right of the black blower unit(being carful to only go in a few millimeters with the drill. You can the put a screwdriver in and feel around to see how much space is available to do the main cutting. Once you're comfortable with the amount of space and where not to cut, cut it open (I initially used a jigsaw, then tin snips). Replace the unit & glue it back together again with a heated glue gun.

Obviously this procedure should be done with care, but it saved me from an expensive and unpleasent repair job.

Laguna Heater Matrix - stevethefirst
Hi Stuart
Thanks very much for the tip it worked a treat.I followed your procedure,the only thing i did different is that i have a Homebase Rotary tool set which comes with six miniature circular saw blades which was perfect for cutting through the plastic blower box because they prevented me from going to deep.
After using my glue gun to put the box back together i also covered the joint with ducting tape (tough Grey type) just to make sure i had no leaks from the blower.
A second hand Matrix cost me £23.00 plus three hours of my time Job Done thats a lot better than the £600.00 i was quoted by my local garage.
Once again many thanks and anyone in the same situation Don`t hesitate give it a go and get the problem solved......stvethefirst
Laguna Heater Matrix - Dastardly
This is going to come in very handy when I tackle this. I was going to just by-pass the heater matrix altogether so that at least the car doesn't run hot.

Feels a bit cold in the car already and it's only early October so I'm thinking again and will have a stab at doing this the "bodge" way.

Thanks a lot!

Edited by Dastardly on 03/10/2008 at 16:24

Laguna SERV light and limp mode - Dastardly
Hi all,

Would appreciate any help you can offer on this. 98 Laguna Auto with a blocked heater matrix. The car still runs fine, but when the engine gets warm the SERV light illuminates and puts the gearbox into limp mode which is gear 2.4 and a max of about 60mph.

This occurs when I put the correct amount of coolant fluid into the system, however, with or without the blocked heater matrix, it seems to happen randomly and even then, when I remove some of the water from the cooling system, the car runs warmer but the SERV light doesn't come on.

Until I can fix this heater matrix, anyone got any ideas how to disable this stupid limp home mode? I've recently been hundreds of miles without this problem and suddenly it's back again. I did see an article a while ago that it is possible cut a wire under the air filter housing, joined to the auto trx. But I'm unsure which wire/s to cut. Anyone done this or heard about it?

I was going to just by-pass the heater matrix altogether but it's getting cold out there and I just want it fixed as it should be.

Would appreciate any help you can offer, many thanks...

Edited by Dastardly on 03/10/2008 at 16:38


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