Heater Matrix leak, smell of coolant in the passenger cabin

Hi, I've got a 55 plate C3 1.4 petrol Desire. There is a coolant smell in the vehicle and it is using a little bit of coolant, I'm suspecting it could be the heater matrix. Has anyone got a guide/tips how to remove the matrix? Does the dash have to come out?? Many Thanks

lihpsl53 wrote:Hi, I've got a 55 plate C3 1.4 petrol Desire. There is a coolant smell in the vehicle and it is using a little bit of coolant, I'm suspecting it could be the heater matrix. Has anyone got a guide/tips how to remove the matrix? Does the dash have to come out?? Many Thanks

The heater matrix is the same for both petrol and diesel engines. You need to remove the glove box to give you access to the heater matrix. You could try some K-Seal (from here) if its not worth all the work taking the glove box out to get at the heater matrix?


Does the C3 have the correct colour (PINK) coolant in the heating system, or is it brown, blue, green or yellow?

Thanks for this. I've just had the cylinder head gasket replaced so I think i'll stay away from the K seal and take the glove box out. The coolant is pink and the garage tell me they flushed the system and replaced it but I'll probably do this again after I've cured this problem. Do you have or know of a step by step guide for removing the heater matrix? Cheers.

lihpsl53 wrote:Do you have or know of a step by step guide for removing the heater matrix?

The C3 Haynes Manual (amazon) has a step-by-step guide to replacing the heater matrix. It a drain down, disconnect the pipes (remove the air filter box for better access) remove the glovebox unit, detach any wires in the way, reach up to remove the heater matrix.

Thanks, I'll get a Haynes and see how things go!

OK, got a haynes manual and after checking the coolant again decided to do a full flush as it looked rusty coloured now and the tester I have wasn't registering any antifreeze properties at all on the float!
All went well drained and flushed, used a bottle as a header tank, found the bleed screws on the side of the cylinder head and the inlet to the heater matrix but............. as I was just finishing off and tightening things up I managed to strip the thread on the cylinder head bleed screw. Arrrgh! I wasn't using much force so suspect it was on its way but of course it is dripping coolant now

Anyhow I have put some plumbers threadlock on hoping that this will cure the leak, letting it cure overnight so fingers crossed in the morning!

Has anyone experienced this before?
Any ideas just in case the threadlock does not work?
Can I still bleed the system through the other bleed screw?
Does the bleed screw go direct into the aluminium head or something else? If its the head could it be tapped and a larger screw used?

Please help!

lihpsl53 wrote:Anyhow I have put some plumbers threadlock on hoping that this will cure the leak, letting it cure overnight so fingers crossed in the morning!

The system gets to full pressure when its hot, so it will need a run.

lihpsl53 wrote:Can I still bleed the system through the other bleed screw?

You will be bleeding only one part of the system there are 2 bleed points because 2 are needed.

lihpsl53 wrote:Does the bleed screw go direct into the aluminium head or something else? If its the head could it be tapped and a larger screw used?

That is a good question. I don't have the answer but if a bigger screw can't be used you could try an original screw and a helicoil insert (some kits on ebay) could be an option.

I think you will have get the engine degreaser out and a bright torch to investigate the head....

Thanks for your reply, I will give it a good run in the morning with my fingers crossed!

Well, gave the car a good run this morning and ................ it seems all ok.

Upon closer inspection of the bleed screw it is screwed into the coolant outlet housing which is bolted to the flywheel end of the cylinder head so this is a seperate part to the cylinder head. Not sure what the internal thread is made of but the screw appears to be brass.

Overnight I thought if it needed bleeding again i would just loosen the top hose and do it that way and see if it worked but it seems fine and I've not had to bleed it.

Annoyingly engine management light is now on,car runs fine but must have disturbed something!?

I've attached photos of the coolant outlet housing with the bleed screw visible and of the sealant I used.

lihpsl53 wrote:Well, gave the car a good run this morning and ................ it seems all ok.

Good news

lihpsl53 wrote:Annoyingly engine management light is now on,car runs fine but must have disturbed something!?

Connect up a cheap OBD2 reader from this link and it can help you work out what got disturbed