Technical Heater problems

[gordinir8]

Just got my 500 today and i noticed that there is no hot air coming into the tunnel. Also there is a heavy ''engine'' smell in the cabin.

What i have done so far is:

1. Checked all hoses and they are there. Including those in the trunk.

2. Tunnel flap operates and i have also checked and confirmed this with endoscope camera but i noticed that when it is open it looks kind of blocked so further investigation needed here.

3. Thermostat flap is always open whether engine is cold or hot.

Question.

Thermostat flap should be closed when engine is cold or should be open?

When hot air is directed to the cabin, when flap is closed, open or in both positions?

What about the oily smell in to the cabin? I have to add here that when i disconnected the hose that goes from the engine to the tunnel smell reduced.

Is the tunnel removable and how hard is this?

It is my first contact with this car and trying to understand how it works so i can fix it.

 

[fiat500]

1. Your thermostat is probably broken, missing or disconnected. The flap has a spring so when it fails the flap stays open.
2. The flap should be closed when the engine is cold and open by varying amounts according to the engine temperature.
3. Blown air can reach the heater duct regardless of the engine temperature as the duct branches off before the thermostat. It will blow cold at first but heats up very quickly. To adjust the cabin temperature you can have the flap slightly open or closed to reduce the flow. You have found the two adjustable flaps under the dashboard?
4. The tunnel can't be removed but all of the hoses obviously can.
5. The hot air in from the heater has already passed over the engine barrels and any oil or fume leaks are carried with it. The 500 engine can be a leaky thing so the smell is an indicator that you will have work to do. In the worst case when the head gasket blows, although there is a built-in safety mechanism, you may get gases blown through the head gasket and into the heater flow.
If you do searches on this Forum you are very likely to have most questions already answered to some degree.
Good luck, keep us posted and where are the photos?

 

[gordinir8]

So first thing will be to remove and check the thermostat to see what is going on but also clean the hoses, there is something in there. Here are a couple of pics of my little car.

 

[fiat500]

Here are a couple of pics of my little car.

Nice colour. Katieb

 

[gordinir8]

Regarding the thermostat are there two types available? Besides the bellow type is there also a spring type from fiat 126 that fits 500? I guess it will be easy to find one local.

 

[cambio]

Yes the old style bellows (alcohol filled iirc) and a more modern style wax filled spring type. You can't see it when fitted, I replaced my old bellows type with a wax filled, on the basis its probably more reliable.

 

[gordinir8]

Thanks, found one and I will take it.
But first I want to remove and test mine.

 

[gordinir8]

So i just opened the panel at the rear of the tunnel and it was blocked with a piece of rag! Probably on purpose but i don't know the reason. Maybe to cut the fumes in the cabin or to reduce heat during summer time, i can understand that the flap is not sealing 100% the tunnel but it was a stupid move anyway.

Now tried to remove the thermostat housing in order to see what is going on with it. I guess i have to remove the distributor so i removed the 13mm retaining nut and pull the thing but nothing moved. I didn't apply lot of force in order not to damage anything. My distributor is the lower in the picture (which i found in here) so correct me if i am wrong but if i remove it then there is no need to adjust timing again.
Any tips about how to remove it?:slayer:

 

[fiat500]

Mine got stuck like that at first and it took quite a lot of penetrating oil and gentle sideways tapping with a rubber hammer to loosen it.
Why don't you remove the other 10mm nut and just take off the top half. That way you don't disturb the timing either.

 

[gordinir8]

To my understanding the 10mm nut is for the timing so if i remove this and split distributor i have to readjust timing, of course i can always mark it and put if back again.

 

[fiat500]

To my understanding the 10mm nut is for the timing so if i remove this and split distributor i have to readjust timing, of course i can always mark it and put if back again.

I see what you mean,,,yes it will need fine tuning but that it easy and you may as well set the points gap at the same time. By removing the 13mm nut and the whole component you have a more tricky job as the drive teeth can go back in many different places. Best thing is to turn the engine by hand until the timing marks line up, then remove the 10mm nut and separate the distributor taking note which direction the rotor arm is facing for wh you put it back. This way there are only two ways it can go.

 

[gordinir8]

ill give it a try, if something goes wrong then i will have to adjust timing, not the end of the world! I must buy haynes manual for all this things

 

[the hobbler]

Before you take out the distributor, run the engine and check the operation of the heater. Even with the thermostat flap fully open, you will still get a fair bit of heat through to the car--it just takes longer to come through. With the in-car heater flap fully closed, very little heat comes through. If the rag was put there to prevent fumes, check for oil-leaks in the push-rod tube area, as this is the main area of leaking that puts fumes into the car.

 

[gordinir8]

Well no without the rug there is some kind of air coming to the cabin but not very strong, I don't know how big or small the flow should be but it is better than before. I will change the thermostat anyway, with the flap close you have all the air coming to the cabin.
I am starting to thinking for a 650 engine/gearbox if I find a cheap one and overhaul it to 0 hours. I don't know yet.

 

[gordinir8]

So tonight i removed the distributor and thermostat housing. I removed the thermostat and it seems like it is expanded, i boil it anyway to see what will happen but as you can imagine nothing happened. Flap has one of its two hinges damaged, hole is deformed. I try to pull the rod with my finger and it really needs a lot of force to overcome spring and close the flap. Is thermostat so strong? of course flap is not operate correct because of the worn hinge and i must first repair the housing.
Now inside the cylinder area and head there are traces of oil but nothing really serious, maybe the fumes in the cabin is because inlet duct (the big one) is torn and engine sucks air from engine bay which is probably contaminated.
Any thoughts?:slayer:

 

[Luxe]

Yeah it is sucking ib warm air from the engine compartment with that air hose damaged. Cheap and easy to replace. The engine will cool beter too.

 

[fiat500]

Flap has one of its two hinges damaged, hole is deformed. I try to pull the rod with my finger and it really needs a lot of force to overcome spring and close the flap. Is thermostat so strong? of course flap is not operate correct because of the worn hinge and i must first repair the housing.

It is correct for the spring to be very strong, but it is constantly trying force the flap open, so it actually helps the thermostat once the alcohol inside turns to gas and therefore expands.
The Laws of Physics also help when the engine cools, as the alcohol has to return to its more dense, liquid state, which forces the thermostat bellows to contract.

 

[gordinir8]

Thermostat housing was bend on one side, bushing was worn and shaft also was very warm. I made a new bushing, repair the shaft and reshape the housing. Flap now is free to operate smooth. Waiting for a new thermostat.

 

[gordinir8]

Another think i want to do is to change heaters on/off flap rubber seal. Is there any way to remove the flap and put a piece of rubber there? a new spare part perhaps?:worship: