General Heater blowing cold air help!

[smithy882]

Hi,

My heater in my fiat Punto only blows cold air. I have had the thermostat changed and the heater matrix flushed through and for a while the air was warmer (still not hot though) but now it is just cold again. Does anyone have any ideas what else i can try as i dont really want to have to fork out to have a new heater matrix fitted as this will prob cost as much as the car is now worth! Coolant level seems fine so i am pretty much out of ideas.

If anyone has any suggestions at what i can try i would be very grateful.

Steven.

 

[bredsticz]

Hows your head gasket? Any signs of failure?

 

[KrisMk1]

Does sound like the head might be on its way out, try and get a pressure test done, monitor fluid levels and check for mayo like substance on filler cap

Thanks
Kris

 

[rallycinq]

Are you sure the coolant level is unchanged?

Cheers

SPD

 

[smithy882]

Hi,

Not sure about the head gasket, will try and get a pressure test done. Would it not be the heater matrix then?

Steven.

 

[smithy882]

Coolant level seems fine.

 

[DaveMcT]

Air in the system can stop coolant flowing and lead to blown head gasket. Bleed it properly.

 

[smithy882]

Hi,

I checked the water level the other day and it had dropped so i have topped it back up and it has held the same now. I also released the bleed screw but there didnt seem to be much air in there, anything else i can do?

 

[smithy882]

Hi,

I have been assured that it is not the head gasket, so do you think it points towards the heater matrix?

 

[Ffoxy]

Hi,

I checked the water level the other day and it had dropped so i have topped it back up and it has held the same now. I also released the bleed screw but there didnt seem to be much air in there, anything else i can do?

Water level...? If the car has always been cooled with just water there could be all sorts of corrosion nasties ahead....

 

[rallycinq]

To echo ffoxy. Are you using coolant not water?

Cheers

SPD

 

[MikeSalt]

First of all, check that hot coolant is actually getting to the matrix. Tie back long hair and remove your tie before leaning over the running engine, and feel the pipes leading to the heater matrix. One should be a little warmer than the other.

Also, if you have a mk1, there's a sneaky little trick you can do to check that the hot/cold air flap and its cable are intact. With the fans off, turn the heater control from min to max and back, feeling carefully how much resistance there is. Then, turn the fans to max, and repeat the same operation. If the is noticeably more resistance, then the flap is Ok. If it feels about the same, then either the flap has broken loose or the control cable has snapped.

 

[DaveMcT]

Things to check:
water pump is actually pumping
coolant level is correct
pipes bled and checked
thermostat working
Heater valve is working

 

[smithy882]

Hi,

I have checked the coolant level and this is fine. I have spoken with a mechanic and he said he has a feeling its not the matrix but that it could be the water pump thats faulty. I am a bit hesitant however to keep throwing money at this unless i know it will defintely do the trick.

It also recently had a new thermostat.

 

[bredsticz]

Could be a simple air lock? Water pump works mechanically on the timing belt doesn't it? or is it different that the 1.2 8v? If so then only way it can fail surely is to leak?

Also, Mikesalt what did you mean by the fan controls? My heater fan controls in my car recently got rather stiff and have to put a bit of effort in to change settings, which I've never had before!

 

[RB2009]

I think waterpump, can be dismissed as being to blame.

if a water pump fails.. you would know about it.. trust me.

1st.. if it was leaking you would have rusty water type marks and visible leakage/dripping.

2nd.. your engine would quickly overheat and likely boil over.

because if the water isnt circulating it wouldnt be getting to the radiator.. and it would therefore boil over and you would know because 1) the guage would go into the red.. and 2 you would have steam everywhere.

Id go with eigther an airlock, thermostat, or heater matrix.. because you have had the thermostat replaced.. id say heater matrix is more likely.

Ive just got 1 for another punto, mk2.. and the heater core channels are really quite narrow.. so neglected antifreeze changes etc would most definitely cause 1 to corrode up or get blocked... and when i say narrow channels they are only about 2.5mm wide so it wouldnt take a lot to block it up. Bearing in mind blue antifreeze needs changing every 2 years.

Flushing it through certainly with a hosepipe or something wouldnt unblock 1.. to unblock 1 you would be looking at power flushing it under pressure... certainly if done with a hosepipe it wouldnt do alot, and the pump itself would of been a more effective means of flushing it out with clean water because it would of been under pressure and force flushed by the pump.

only time you use a hosepipe to flush is if you need to change the antifreeze colour. But I dont know what method was used.

 

[bredsticz]

Could be the very start of a pump leaking? Very slight wouldn't make much difference at all! Untill it gets worse of course!

 

[RB2009]

even at the very start though, you would see visble dripping from it/ coolant loss
and even if it is leaking it should still be pumping water around, not so often that the impellor on the pump fails, its more usual for its bearings to start leaking causing a coolant loss.

 

[bredsticz]

He is having coolant loss :S

 

[bredsticz]

Ah sh*t, ignore me I thought this was a different post! If there's no coolant leak just pretend I was never here, if you do have a coolant leak then it could be pump (possibility)!

*vanish*