General No heat inside uno

[JRB21]

Hi there, I hope somebody can help me.

If have a '95 Uno Fire 1100. I cannot seem to get any heat inside the car (has never worked before). I recently fitted a new radiator, old one had a crack in, but now my radiator cap keeps on dripping coolant out, and I cannot seem to stop this. I don't know much about cars, but is it very important to bleed the coolant?

Any ideas on how to stop the leak at the cap and get hot air inside the car, 'coz it is winter here now, and I need the heat.

Thanks

 

[Chas Uno]

Radiator cap can be one of two things:

One, your car is overheating and the cap is doing its job of relieving the pressure in the system. You car should be running around the 90 degree mark and then have the fan kick in. If it is running much over 100 then you could have a problem somewhere. It could also be because the system needs bleeding (as you asked) because you may have airlocks in the system causing hot spots.

Two, the cap itself might have failed. It's worthwhile simply replacing it with a new one (they're not expensive) to see if that might solve the problem.

As for the heater itself again it could be one of two things:

One, the heater matrix valve has failed and is stuck shut. You can see the heater matrix from the driver's footwell - look for two pipes coming into the car behind the dashboard/ centre console area. They should be just above and to the left of the clutch pedal arm - you can also see these two pipe going into the firewall/ bulkhead from the back of the engine. With the car running at operating temperature and the heater set to 'on', feel the two pipes. If one is hot and the other is cold then the valve has failed. If both are hot then the air distribution flap has failed though I'd suspect it's more likely that the valve is at fault.

Two, the matrix might be clogged up causing insufficient flow. Your cooling system would probably have to be in poor condition for this to occur though. If you suspect a blockage then you can disconnect the pipes at the bulkhead in the engine bay and then use a hosepipe to reverse flush it. You will know if it is blocked as water won't flow out of the other pipe. If water flows freely then you will at least establish that there isn't a blockage.

Let the forum know how you get on and good luck!

 

[JRB21]

Thanks 1986Uno, you are always there to help me, I appreciate it.

The heater knob only turns a little bit then it starts to click. Will you be able to back flush it if the valve is stuck, or not. And if the valve is stuck, can I manually open it, or do I have to get a new one.

 

[Chas Uno]

Thanks 1986Uno, you are always there to help me, I appreciate it.

The heater knob only turns a little bit then it starts to click. Will you be able to back flush it if the valve is stuck, or not. And if the valve is stuck, can I manually open it, or do I have to get a new one.

No probs JRB21, that's what the forum's for! Don't forget that if my advice is useful you can always press the 'thanks' button in my posts (the little thumbs up sign).

Ok, so from what you described with heater knob going 'click' it sounds as if either the cable has jammed, the knob itself is faulty or the valve is stuck.

You cannot back flush the heater matrix if the valve is closed as it shuts off the coolant supply, and the bypass hose in the engine bay will return coolant sent to the matrix back into the engine cooling system. The valve must be open for coolant to flow.

First thing to do is check to see what the valve is doing. I've attached a picture below of what to look for. Whilst looking at the heater valve arm operate the heater control (hot/ cold knob). You should see the cable pull the lever back and forwards. If the arm doesn't move then your problem lies with the heater control knob and/ or cable.

If the cable/ control knob appears to be faulty then you can still operate the valve. You will need to release the cable at the valve either by removing the screw that clamps the outer cable to the valve (arrowed) or releasing the inner cable from the arm. This will allow the valve to be moved freely by hand and you then will be able to establish whether it is flowing coolant or not.

Hope this helps!

 

[JRB21]

Fixed cable, valve opens now. The two pipes in the engine bay at the back are hot, but when feeling the pipes inside the car, they are cold. Flushed heater matrix (hosepipe into the bottom pipe, and very filthy water came out.

But still no heat!!

The flap opens, the matrix is flushed out, valve operates, what else could it be.

 

[alexGS]

Fixed cable, valve opens now. The two pipes in the engine bay at the back are hot, but when feeling the pipes inside the car, they are cold. Flushed heater matrix (hosepipe into the bottom pipe, and very filthy water came out.

But still no heat!!

The flap opens, the matrix is flushed out, valve operates, what else could it be.

I would say that even though the lever on the valve is now moving, the valve itself may be jammed shut. This has happened to me before. The flow is restricted enough to ensure there's no flow through the matrix, even though you managed to get enough flow during your flushing to get "very filthy water" out (I know exactly what you mean).

The only solution is to unbolt the valve from the heater matrix (easy to do, but put a bowl in the footwell first, obviously) and inspect it. You may be able to clean it with oven cleaner and boil in a saucepan etc., or you might just replace it.

-Alex

 

[Chas Uno]

Fixed cable, valve opens now. The two pipes in the engine bay at the back are hot, but when feeling the pipes inside the car, they are cold. Flushed heater matrix (hosepipe into the bottom pipe, and very filthy water came out.

But still no heat!!

The flap opens, the matrix is flushed out, valve operates, what else could it be.

Alex I reckon is spot on with his reply. Most probably a faulty valve.

However, there are a few other things you can check:

With the engine up to operating temperature and the heater set to 'on' (max heat), feel the two pipes in the footwell going to the heater matrix. If one is considerably hotter than the other than it's almost certain that the valve is faulty.

The reason why I suggest checking from inside the car is because in the engine bay there is a bypass hose connecting the inlet and outlet heater matrix hoses. Even with the valve closed the water can still heat up the outlet hose because of the heat transfer across the bypass pipe. This can give the impession that hot coolant is flowing through the matrix when it's not.

Another thing to check is the heater box inside the car. If the matrix is flowing hot water then you will still feel the heat around that area. Also, are you sure that the other heater control ("air control") is set to maximum? It controls the flow of air and I think if it is shut then it won't allow air from the matrix into the car. Also some Unos have an "automatic temperature control" function activated by a switch. Does yours have this and is it switched on or off? See pic below for the controls.

Lastly, what temperature is your car running at? Warmed up the car should indicate 80 - 90 degrees on the temperature gauge. If yours is much lower than 70 degrees then it's possible that the thermostat is faulty and the car isn't warming up enough to heat the matrix.

By a process of elimination you should be able to get your car nice and warm eventually!

 

[JRB21]

Thanks for all the help guys, will try everything this weekend to fix it. will definitely let you know if I get it fixed.

 

[JRB21]

Thanks guys, you are excellent!!! Heater is perfect now. Getting hot air through the foot vents and the windscreen, but not through the main and side vents. Is this normal?

But anyway I am happy. At least there is heat inside my car for the upcoming winter. Thanks a lot!

There is a screw on the inlet valve with a moving plate thing that opens the valve and closes the valve. That screw was loose enough so the plate moves, but not the valve itself. Tightened screw and sprayed some multi lube into the valve and fiddled with it for about a half an hour. Works perfectly now.

Now, I have yet another problem. Had this posted before, but it is happening again...

My rear brakes are stuck again. The rear wheel cylinders work perfectly. I overhauled them a few months ago. It is fine if I drive it everyday, but if I let my uno stand for a week or so, the rear brakes do not release at all.

Any ideas??

 

[Chas Uno]

Glad to have been of help and to keep another Uno on the road

Getting hot air through the foot vents and the windscreen, but not through the main and side vents. Is this normal?

Yes, this is normal. The centre vents and large side vents are non heated air only. There are also two smaller side vents (non adjustable) that put out heated air to the side windows for demisting purposes. Otherwise the heated air only goes to the windscreen and the footwells.

Now, I have yet another problem. Had this posted before, but it is happening again...

My rear brakes are stuck again. The rear wheel cylinders work perfectly. I overhauled them a few months ago. It is fine if I drive it everyday, but if I let my uno stand for a week or so, the rear brakes do not release at all.

Any ideas??

This is often quite normal as Unos (and other Fiats) tend to seize up their rear brakes if left unused. It's probably one of the following:

1. Brake drums rusting onto the shoes
2. Handbrake cable sticking/ rusting
3. Handbrake mechanism sticking
4. Handbrake levers in the drum sticking/ seizing/ rusting

Number 4 is a very common problem, especially if the rear brakes haven't been touched for a few years. The others might require a little longer than a week to become apparent but it depends on their condition and how damp the weather is where you are.

If you can drive the car with them sticking then do so and apply the brakes a few times (including the handbrake). You may find they will free off on their own accord. If not then you'll have to check the cable and/ or remove the drums to find out where the problem lies.

Good luck