No heat from the heater

[Cavalier342]

As the title says really, i just cannot seem to get hot air to come out of the vents. No matter how hot the engine is, on a cold day i get a faintly warm air flow and no more. And if it does blow out warm, it only lasts for a short period. Would i be looking to replace the matrix? I've checked the scuttle panel drain (elephant trunk), it's unblocked. I flushed the radiator not long ago, i don't really know what else to try. Can anyone suggest anything?
Thanks in advance.
Andrei.

[marcia]

Are the heater control flaps working correctly,may be stuck in cold position? Can you feel heat in the hoses going in and out of the heater from the engine side?
William

[Cavalier342]

I presume by control flaps, you mean the slider? It slides fine from one end to the other. Haven't checked the hoses yet, i'll try that next.
Thanks.
Andrei.

[Cavalier342]

Ok, i've checked the hoses that you mentioned, the one on the cambelt side, is hot, the other one to the right is coldish. They both go through the bulkhead so i assume they're the right ones. So is there a blockage somewhere?
Andrei.

[Gaz]

they should be pretty hot after some running, does your car heat up quickly or slowly?

[Envoy CDX]

Could be a matrix issue, or it could be a stat fault.
As Gaz said, how does the engine heat up?

[Cavalier342]

She warms up pretty slowly on a cold day, but not too slowly if that makes sense. I changed the stat a while ago. She doesn't overheat, usually stays around 80-90 degrees around town. Long idling or heavy traffic, the fan kicks in as it should. From cold, i can get 2 miles and the needle comes out of the blue area. No heat comes out of the fans. On the other hand, in my manual Cav, i can do the same distance and i can get nice heat. Thats why it seems odd.
Andrei.

[Robsey]

The obvious causes for poor heating in the cabin are: -

1) Insufficient coolant, causing a cycle of warm air, cold air, warm, cold and so on.

2) Blocked heater matrix - you've flushed the radiator, see if you can do the same to the matrix, via the two hoses that run through the engine bulk head.
flush right hose and drain from the left , then flush the left and drain from the right.
This sounds most likely as one hose is warm and the other is cold.

3) Very old coolant fluid will not heat up the same

4) The sliders might move, but does the flap lever on the side of the heater matrix casing (driver's footwell) move back and forth. Should be a blue plastic sheath around a steel wire that operates a white platic lever.

[Cavalier342]

Hi Robsey.
Definitely not 1 and 3. I check the coolant level almost daily without failing. I also renew the coolant/antifreeze more than regularly. So, tomorrow i'll have to try the other two methods. Flushing the heater hoses and checking the flap lever in the driver's footwell.
Thanks.
Andrei

[Envoy CDX]

Hi Robsey.
Definitely not 1 and 3. I check the coolant level almost daily without failing. I also renew the coolant/antifreeze more than regularly. So, tomorrow i'll have to try the other two methods. Flushing the heater hoses and checking the flap lever in the driver's footwell.
Thanks.
Andrei

Flush the entire system through, winters approaching

[Cavalier342]

Well, i can only say...







Many thanks guys
I flushed both hoses in the engine bay several times and on the first few times, the amount of brown water that came pouring out was unbelievable. I'm ashamed that i didn't think of doing it before. I flushed them through until clear water came out, refilled the water and antifreeze in the reservoir, took her for a quick spin and the results were amazing. I actually had heat before the needle got out of the blue area. And unlike before, the heat still came out at full fan speed, where as before it went cold. So... thanks guys. Just going to wait for a really cold day to see what it's like
Andrei

[Robsey]

Glad that all is now toasty

However now that you've disturbed the matrix sludge, you need to keep an eye out for possible leaks from the matrix.

The obvious signs will be a damp carpet in the foot-wells.

I don't want to put a mocker on things, but what can go wrong, usually does - well for me at least .

[Cavalier342]

I know, thats my next concern. The first thing i been told i'll notice is a horrible smell in the cabin. Lets hope she pulls through the winter at least.

[Envoy CDX]

New matrix is aboutr £40, so as long as you can afford one should the worst happen, then you'll be find, bit fiddly to get the 6mm nuts out of the baseplate, but certainly doable

[planetc]

However now that you've disturbed the matrix sludge, you need to keep an eye out for possible leaks from the matrix.

pmsl, exactly what I was thinking as I was reading this!

[Robsey]

However now that you've disturbed the matrix sludge, you need to keep an eye out for possible leaks from the matrix.

pmsl, exactly what I was thinking as I was reading this!

Some things are best left untouched - until your teeth start chattering at least !!