No internal heat from heater.

[veggie-burner]

Hello,

I'm not to sure if this should be posted here, can someone help me out please?

I have just aquired a M-reg sallon Mk3 1.8i ,

there is little or no heat comming from the internal heater, the fan works a treat but not much heat,

just before the cold spell hit the heater worked fine and the service history shows that the heater matrix was replaced last year. Antifreeze seems ok to.

has anybody got any ideas please? I have a resonable mechanical knowledge and am fairly familiar with these engines I have stripped several of them down for head gaskets and cam replacements over the years.

but this one has me completely baffled. Has anyone out there had similar problems with their heater?

Thank you in advance . veggie-burner.

[Gaz]

if its the middle vents its always tepid, they dont actuality heat up but the side ones should

Is the car getting upto temp? If not id change the thermostat.

Have you tried to run the car with the cap off, squeezing all the pipes as its running?
once it gets hot all the air should rise to the header tank and escape because there is no cap on.

[humbucker]

are the sliders working? could be detached cable?

[Cavalier342]

Check the thermostat like Gaz said, my heater also takes forever to get warm this time of year, and i know that the coolant and the stat are good. The middle vent is cold, but when the engine really warms up, i do get really nice heat. I dont know if it just takes a while or not, but i'm thinking of just taking panels and trim bits off and shoving insulating material in there to keep it warmish. Anyone else done this yet?
Andrei

[veggie-burner]

"Thanks everyone for your pointers".

I gather the stat is working as the engine comes up to temp ok, but not knowing the normal running temp of a Mk3 1.8i its a guessing game. and my guess is probably wrong. it seems to take absolutely ages and ages to reach temperature idling for at least an hour.

maybe as a precautionary measure its worth just changing the stat, Is there a winter stat for these Mk 3's?

will try bleeding the cooling system with the cap off (engine running) could be an air lock somewhere.

Cavalier342,

I think you have hit the nail on the head "really cold centre vents" the trouble is that is where I expected the most heat to come from and closed all but the centre vents, I shall try it the other way around by closing the centre vents and openning the outside vents instead.

Heater cables are connected ok as you can feel the drag of the cables behind the dash and with the fan on full pelt you can hear the change in air flow from hot to cold.

several things to try I'll post the results here if i manage to find the fault and I hope its soon its Bl**dy freezing inside the car....lol

veggie-burner

[humbucker]

i think dodgy heaters and freezing is just the destiny of cavmk3 drivers...

[Cavalier342]

If i dont carry a passenger in the front seat, i close that vent off, and just have the other 2 open. This redirects more heat to me. If the engine temp is taking forever to reach normal temp (80 degree or so), about 2 cm below the 90 degree mark, then i would definitely recommend the stat to be looked at. Its probably rusty and corroded like mine was before i changed it. Also, it may be worth changing the water temp sensor, next to the stat, as they are pennies, and simple enough to do. Just stick to a standard thermostat for now, you'll know if it makes a difference.
Hope this helps.
Andrei

[Cavalier342]

Well i think i found what could be the main problem with the heat issues. Its the dashboard itself. Starting up from cold it only takes a couple of miles for me to reach normal operating temp, and if i turn the heater on, directly to me, its still cold from all vents. If i turn the slider towards the windscreen(right), even worse. But, if i close all vents and reach forward to the windscreen demister vents, there's plenty of warm air. So the problem is, the whole dashboard unit itself gets freezing cold overnight, so that warm air being generated by the heater system just passes through a cold tunnel out of cold vents, making it useless. Only when the interior is warm, thats when there's plenty of heat coming to satisfy. So thats the problem then. Looks like i'll have to go with the insulating material idea. anybody else recommend anything good?
Andrei.

[humbucker]

mines more or less the same but i put it down to disconnected sliders i.e. heat only comes out of windscreen vents. previous owner advised me of this when i picked it up and said he's had it diagnosed as the slider not connected to the vent direction thingy properly so i need to hook it back up. if you've got hot air i'm not sure the temperature of the plastic dash is enough to dramatically reduce the temperature of the air by the time it leaves the vents. rather, the temp of the hot air would heat up the dash...?!

[Envoy CDX]

Old thermal socks round the plastic ducting for the air should keep the air in Andrei.
As for taking an hour to get to temp idling - I think you have either a blockage somewhere or your stat is permantly stuck open.
Fuel economy is a identifier for that too.

[veggie-burner]

Brilliant,

thanks for your advice everyone, I have now changed the thermostat and we have heat inside the car.

sheared one of the stat housing bolts off and had to drill out the old bolt and re-tap the hole for a new bolt it took 9 hours in the pouring rain at -3 degrees C couldnt feel my fingers or my toes for at least another three hours after that nightmare.

thank god for dremmel drills they fit between the thermostat housing and the radiator (just about).

Happy new year everyone.