306DT no hot air - hm

my 306 has never been great at producing hot air from the vents,

I have checked the blower etc, it working correctly,
I have checked the dial and cable are working and re-directing the air over to the matrix.
I have disconnected the matrix from under the bonnet and put a hose pipe in one end and watched it flow out the other.

I know the car runs about 80°C which is low, but the thermostat works and even if I block the rad until she's at 90° and the fans cut in, she still refuses to produce hot air.

The in and out of the matrix are hot (too hot to hold)

Has anyone got any ideas? I'm lost.

Is it possible for the matrix to fill with grime, does anyone know the flow path, is it possible for the coolant to just be passing over the top and not through the fins.

Removing the entri dash and maxtrix is all I have left to do, but I would rather avoid it. HELPPPPPPP


306DT no hot air - Hawesy1982
I know my '95 306DT does the exact same thing, but not so encouragingly i'm getting rid of it due to the head gasket being stuffed and god knows what else - hopefully thats completely unrelated to this problem tho.

I heard someone mention before that they discovered a crack/gap somewhere in their heating system, which meant that cold outside air was bypassing the matrix and coming straight through the blowers - it may well have been M.M, RichardW or Solara, certainly one of these three will be along with more informative info soon i expect.
306DT no hot air - Hawesy1982
Oh probably a stupid question, just thought have you checked you've got enough coolant? If not this would make a difference i expect.
306DT no hot air - solara
Have you tried bleeding your collant system from the very top bleed screw. This is in the bonnet just behind the intercooler.
306DT no hot air - Andrew-T
I don't think a running temp of 80°C is low for a 306TD. Mine has run just below 80 for over a year (admittedly it's a HDi) and still does after a coolant change. I get warmth from the heater after a couple of miles.
306DT no hot air - Chambo
Any help

306DT no hot air - Crinkly Dave
When you tried the hose the matrix inlet, did you get a trickle, or a strong flow? The matrix should offer little resistance.
Have you tried the flow the other way to the normal direction also?
Do both pipes get hot when the engine is hot AND the engine revving above 1500rpm (may be little flow at idle)?
Have you checked that the controls actually do anything? The matrix should stay at the same temperature, and temperature control at the vents is achieved by varying the amount of cold air bypassing the matrix. You will have to check the Haynes, and then get a mate to move the heat control while you make sure the flap on the heater moulding actually moves.

306DT no hot air - DL
Is there a rapid circulation of coolant in the expansion tank on the end of the radiator?

If so, that would discount any circulation problems.

Perhaps a surface thermometer against the radiator top hose, heater hoses and matrix (if accessible!) might throw some light on it?

The heater air distribution flap theory sounds credible to me.

groups.msn.com/honestjohn - Pictures say a thousand words.....
306DT no hot air - voodoo
Different car (Golf VR6) but similar problem, low engine temp and no cabin heat, turned out to be missing vanes (7) in water pump. Just a thought. New pump fixed problem - now warm as toast.

Ask Honest John

Value my car