Technical Panda 1.2 Heater blows cold and overheating :(

[mitchk]

noticed last night on my way home that my temperature guage was quite high and the radiator fan was continuously on.

I turned the heating up to full hoping to take a bit from the engine but it just blows cold. Luckily I don't live far so got home before it overheated.

Had to get a lift in this morning but will try and diagnose tonight when I get in.

The only thing I can think off is occasionally I have noticed a gurgling sound like there is trapped air in the system. It has been doing this for 6 months or so since I changed the thermostat at Xmas.

The car does not use any water, does not seem to have any water in oil and starts/runs fine.



I'm hoping that there is just and air lock in the system somewhere so when I get home I will :

• remove bottom radiator hose and drain water.
• open radiator vent and heater vent screws.
• top water back up till water comes out of radiator screw and then heater vent screw - tightening them as I go
• put expansion cap back on and start engine with heater on full fan and heat.

I have thought about maybe the thermostat or maybe a bocked radiator, but I don't think I it wouldn't stop the heater from working would it ? I also thought about Head gasket but there seems to be no sign and the engine runs fine.

any idea's on how I could test the water pump ?

and can you think of anything that I have missed ?

any advice much appreciated

 

[portland_bill]

Your process to drain and refill is good. Hopefully you mean coolant, not just plain water. Coolant mix is a powerful anti-corrosive, plain water will cause corrosion, and will block radiators. May be no need to drain, just bleed and top up.

Heater cold indicates no water circulation. Air lock or water pump failure. There have been some reports of water pump impellers detaching, so spinning on their shaft freely, or more likely not spinning. Plastic impellers are to blame, not confined to Fiats. No easy way to check, have to remove, so that's a cambelt job too.

Do your list.
As it warms up, top hose from thermostat should remain cool, then suddenly get hot as stat opens. Radiator should then get hot from top down, across whole width and all the way to the bottom. Don't burn yourself, or get caught in anything moving.
Heater hoses should start to get hot very quickly after engine start.

If stat is stuck closed, heater should get hot quickly.
If stat is stuck open, result should be running cold.

Check header tank for bubbles indicating head gasket.

If all seems ok, pump is most likely. Most new ones have a metal impeller now, don't accept a plastic one.

 

[mitchk]

Hi Mate

thanks for the reply - will use the original water with coolent if not contaminated.

so next question would be how hard is it to replace the water pump ?

I understand that this involves the cambelt but can it be done without complete removal ? also the 1.2 2004 engine I have is non interference isn't it so worst case scenareo if the belt was slightly out would be that it wouldn't start or run very well ?

one thing that I did think strange yesterday was that both pipes going to and from the heater seemed very hot ? but heater output remained cold

 

[portland_bill]

so next question would be how hard is it to replace the water pump ?

I understand that this involves the cambelt but can it be done without complete removal ? also the 1.2 2004 engine I have is non interference isn't it so worst case scenario if the belt was slightly out would be that it wouldn't start or run very well ?

If your oil filler cap is a square push-in cap, cambelt replacement is easier as there are timing marks. Tensioner is manual and can be set by twisting the belt to judge tension. Engine mounting gets in the way, so makes it awkward and more stuff to remove.

If the oil cap is a round screw-in type, special tools are needed to set cam position as there are no timing marks.

Either way, need to replace belt, tensioner and pump using a good manufacturer to avoid issues later. Engine is safe, but performance is significantly reduced is not set correctly.

one thing that I did think strange yesterday was that both pipes going to and from the heater seemed very hot ? but heater output remained cold

Could be related, or a separate issue.
Both pipes will eventually get hot even if no circulation.
Need to start from cold and feel if top heater hose (inlet) gets warm quickly, followed almost immediately by the lower hose. This would show circulation ok.
If no circulation, top hose will warm up, bottom one will take longer as it is warming through heat transfer from the other end, rather than water moving. Could indicate blocked heater matrix or water pump failure.

If water is circulating, but no heater hot output, the air distribution flaps are not moving. Could be broken controls or loose cables.

A Haynes manual, number 5558, search Ebay and Amazon for best price, will help understand all of this, and is essential if you wish to repair it yourself.

Update your profile to show your location. Owners of the tools may be able to offer help if they know where you are.

 

[mitchk]

many thanks again !!

after rebleeding the system last night the heater started working again

Top radiator pipe from thermostat remains cold though so think the thermostat I changed a Xmas has given up already.

Have ordered a new one through shop4parts this time so hope it will last longer

will order the Haynes manual as well as hope to keep the car for a while

will post back if fault is sorted with replacement

 

[Herts Hillhopper]

Have you bleed the pipes to the heater, right at the back of the engine against the bulkhead? This needs to be bled too to get all the air out the system. See this earlier post that explains how: https://www.fiatforum.com/panda/229229-heater-problems.html?p=2426485

 

[mitchk]

yep - turned out to be the thermostat after all that !!

the circoli one that I put in 6 months ago must have stuck shut.

one thing I can't sort though is that it still gurgles frombehind the dash. I think this is the air conditioning system though ?

Regards,

Mitch

 

[A3jeroen]

Probably still air trapped in the heater matrix.

gr J

 

[portland_bill]

Check the scuttle drains too, water sloshing in there can gurgle. (Been there, done that, got the goldfish.)