Technical Heater blowing cold air

[JTG0710]

Hi all Punto has stopped blowing hot air.

Coolant level good and bled properly. No leaks
Head Gasket sound.
No overheating.

Surly cant be thermostat ? As its running at normal temp

Any ideas ?

 

[flisko]

maybe its blocked somewhere, i would catch old coolant if it was changed in last 2-5 years and put tap water in a few times to try to unblock it then run it to temp with tap water and if you got heat commin through wait till it cools down and put coolant in

 

[Brendan W]

Airlocks are the first suspect in cases like this. Is there a gurgling noise from the heater at startup ?
Blockages can happen especially if someone has used leak fixer in the coolant. With the car warmed up the hoses to the heater should be quite hot. The coolant should be circulating there all the time.
If there is no airlock and no blockage then maybe the air control flap for the matrix is stuck closed or disconnected from the selector knob.

 

[judderbar]

maybe its blocked somewhere, i would catch old coolant if it was changed in last 2-5 years and put tap water in a few times to try to unblock it then run it to temp with tap water and if you got heat commin through wait till it cools down and put coolant in

I think the heater dial operates a flap to direct the cold cold air thru the heater and the connection between the two can break?

 

[oldhammer]

Is the pipe to the heater getting hot?

the one with bleed screw on.

if not, Replace stat,

 

[JTG0710]

No air locks , heater flapper works as you can hear the change it air through the vents

The heater hose with the bleed screw is hot

Car isn't overheating

 

[judderbar]

If you do the following you can check if the heating element is blocked or not.

Unscrew the filler cap and make a note of the coolant level using a light shining on the outside of the tank, then open the top bleed screw at the back of the engine (where you felt it was hot) and check the coolant level rises in the tank so you are sure you have introduced air into the system. Tighten the bleed screw and check you can hear gurgling noises from the heater element as the air and water passes thru the heater when you are in the car with the engine running.