Technical Manual AC - just checking others' experiences

[Bonefish Blues]

Morning all. Just a couple of queries about the AC's capability in this series.

Our 4x4 Multi was slow to warm in winter - no surprise there then, you say. However, now we're starting to have warm days it's clear that as predicted (ish) on a full inspection by the Royston Fiat specialists, the cooling power's very limited too, because the condenser's degrading, and fins are falling off.

A couple of queries if I may - I'm assuming that the slow warm in winter issue's nothing to do with the condenser - is that correct? Second Q is really just the ultimate cooling capability of the manual system when fully working - Just checking that it's more than adequate to cool the car on hot days?

 

[AndyRKett]

Warming has nothing to do with the condenser fins

If anything they would block the airflow through the radiator behind the condenser and cause the coolant to heat the car up faster once the thermostat opened.

The air conditioning system should be perfectly adequate to cool the car, but the insulation in the cabin of most fiats is poor meaning of it is not working 100% then the aircon will struggle.
Sometimes you’ll need to set it to full cold just to try and keep the temperature in the cabin comfortable especially if it is a very bright sunny day.

 

[varesecrazy]

Hi
We have twinairs and Diesels

The twinair aircon..probably identical through all models is OK in the Panda..but takes a while to cool a similar Punto..double the air volume being why


Diesels are efficient.. burning less fuel means less wasted energy
So less byproduct heat

Diesels take twice as far on my morning commute to crawl off the C of the temp gauge compared to a TA

RECIRC obviously aids cabin temperature.. as its not dealing with putside air

But can get quite stuffy quite quickly :-(

 

[Herts Hillhopper]

Agree with the above posts. I have a 2018 MultiJet 4x4. It's slow to warm in the winter, which is why I was lucky enough to find one with the winter pack (heated seats and heated screen) which overcomes the issue of slow heart generation.

The aircon is fine - but you need to have the blower on at least speed 2, 3 is better. And recirc will cool it faster and keep it cooler longer (that's why recirc is there

The panda has a lot of glass relative to cabin space so acts like a greenhouse. This is made worse if you have the dark tinted rear windows, as these being black, get heated by the sun and transfer more heat into the car than the lighter ones do (never understood the point of dark windows - they always warm things up)

 

[The Panda Nut]

I have had a disintegrating condenser on our 2011 Panda and have heard this is not unknown. That condenser still cooled the car pretty well but was literally disintegrating and I didnt want uncontrolled release of gas to the athmosphere so had it changed.

Lack of cooling will be due to low pressure in the system. Agreed the most likely culprit is the condenser. Denso supply the original equiment and are readily available outside of the Fiat network at more realistic cost, All my Panda air con systems have been well up to the job of cooling even last year all three of our Pandas could get the temperature down quite quickly.

 

[Pugglt Auld Jock]

I have had a disintegrating condenser on our 2011 Panda and have heard this is not unknown. That condenser still cooled the car pretty well but was literally disintegrating and I didnt want uncontrolled release of gas to the athmosphere so had it changed.

This is exactly the situation with Becky's (2010 1.2 60hp). Every time I go under the bonnet I notice some some "metallic snow" which is little pieces of the fins. I haven't asked Kenny how much it will cost to replace. Might wait till MOT time and do it then if there are no dramatic other problems. In the meantime it continues to function quite well but I do notice the compressor seems to cut in and out more frequently. My mind's more occupied thinking about the corrosion on the rear spring pans right now!

 

[Marcus Daly]

The panda has a lot of glass relative to cabin space so acts like a greenhouse. This is made worse if you have the dark tinted rear windows, as these being black, get heated by the sun and transfer more heat into the car than the lighter ones do (never understood the point of dark windows - they always warm things up)

I can’t get past the front and rear windows not matching. Always looks wrong to me.

 

[The Panda Nut]

This is exactly the situation with Becky's (2010 1.2 60hp). Every time I go under the bonnet I notice some some "metallic snow" which is little pieces of the fins. I haven't asked Kenny how much it will cost to replace. Might wait till MOT time and do it then if there are no dramatic other problems. In the meantime it continues to function quite well but I do notice the compressor seems to cut in and out more frequently. My mind's more occupied thinking about the corrosion on the rear spring pans right now!

Thr part for the 169 is a lot less that the 319 its the gas and labour. I guess at a local garage £250. Gas is the expensive bit!

 

[Pugglt Auld Jock]

I can’t get past the front and rear windows not matching. Always looks wrong to me.

Always reminds me of a hearse? But hearses don't have dark rear windows so why I think this I don't know!

My youngest boy seems to be obsessed with this, he's already done the rear windows of his "new" car. What I really don't like though is the closed in feeling it gives and the reduction in awareness of what's going on behind you when driving. It's like keeping your rear view mirror in permanent dim dip mode. Just not for me.

 

[varesecrazy]

My punto has the rear door glass with a factory tint (privacy glass)... a PIA when it got broken as it took days to replace (non.stock)

Definitely harder to see in.. but from a drivers perpective no darker than the 3 door variant with 'normal' tint

If you spend enough times driving vans..or towing... the Rear view mirror becomes secondary

 

[Marcus Daly]

My punto has the rear door glass with a factory tint (privacy glass)... a PIA when it got broken as it took days to replace (non.stock)

It was the only option I didn’t take when I bought my Panda.

It came as standard on my old Lexus, but that was black and so it didn’t look quite as weird.

 

[varesecrazy]

It was the only option I didn’t take when I bought my Panda.

It came as standard on my old Lexus, but that was black and so it didn’t look quite as weird.

Mine was Standard

The Twinair model punto came with most of the options.. and most of the Grande niggles

I still like it though

 

[AndyRKett]

This is made worse if you have the dark tinted rear windows, as these being black, get heated by the sun and transfer more heat into the car than the lighter ones do (never understood the point of dark windows - they always warm things up)

not quite right. I can’t speak for your experiences but every window tint I’ve ever encountered does the opposite,
They should block a lot of the infrared and ultraviolet that causes the cabin of the car to heat up.

A lot of the heat comes from IR and Ultraviolet causing surfaces within the car like the seats and dash to heat up and radiate heat, the windows stop the heat from escaping.

Most tints are rated for how much they block IR and UV
I had the windows tinted on my Mk2b Punto and afterwards was notably cooler in the summer months

 

[KPat]

Some cars like the Citroen C4 have pull up mesh blinds. Much better idea.

 

[Panda IIs]

Always reminds me of a hearse? But hearses don't have dark rear windows so why I think this I don't know!

My youngest boy seems to be obsessed with this, he's already done the rear windows of his "new" car. What I really don't like though is the closed in feeling it gives and the reduction in awareness of what's going on behind you when driving. It's like keeping your rear view mirror in permanent dim dip mode. Just not for me.

Are we talking about "drug dealer" glass here?

 

[Mouse1903]

Darker the tint the more heat it should keep out of the car

 

[Bonefish Blues]

Darker the tint the more heat it should keep out of the car

Not necessarily, seemingly:

Does Dark Tint Equal More Heat Rejection? - Shane's Tint

Tint companies are asked the question, "how dark will my tint need to be to block heat?" For them to understand we review these things with our customers.

shanestintandclearbra.com

Anyhow, it's a bit of a sideshow on a Panda as the untinted windscreen & front windows must represent 60-70% of the total glass area, I'd estimate?

 

[Panda IIs]

Darker the tint the more heat it should keep out of the car

Err, is this the case, seems counter intuitive re the physics of it? If a mirror finish I wouldn't disagree but dark shade doesn't seem to offer much in the radiation reflection stakes? Any way sideshow as noted above!

 

[AndyRKett]

Err, is this the case, seems counter intuitive re the physics of it? If a mirror finish I wouldn't disagree but dark shade doesn't seem to offer much in the radiation reflection stakes?

You are not blocking heat you are blocking light, light which when it comes into contact with the plastics and materials inside the car is turned from ultraviolet and infrared light, into heat energy.

This is why on a hot day a car interior can be considerably hotter than the air outside, because the car is trapping that light energy as heat inside the car and it can’t get out so the heat builds up.

The tint is a few microns thick the mass of the dark material is next to nothing but the amount of light that it blocks from getting into the car means that all that light energy isn’t turned into heat inside the car.

Obviously these tints are just a film of plastic they do not get very hot or they would just melt. So the dark plastic tint does not have enough mass to accumulate much heat at all and they are stuck to a glass window which is terrible at absorbing heat

 

[Panda IIs]

You are not blocking heat you are blocking light, light which when it comes into contact with the plastics and materials inside the car is turned from ultraviolet and infrared light, into heat energy.

This is why on a hot day a car interior can be considerably hotter than the air outside, because the car is trapping that light energy as heat inside the car and it can’t get out so the heat builds up.

The tint is a few microns thick the mass of the dark material is next to nothing but the amount of light that it blocks from getting into the car means that all that light energy isn’t turned into heat inside the car.

Obviously these tints are just a film of plastic they do not get very hot or they would just melt. So the dark plastic tint does not have enough mass to accumulate much heat at all and they are stuck to a glass window which is terrible at absorbing heat

Well from my physics, I think the UV converts to infra red spectrum when passing through glass otherwise we would all get sun burnt in side the car and truck drivers wouldn't need to wind their windows down... However I think the general principle is correct?

This is why the car heats up inside - all that extra infra red. As the link above suggests you can create UV and IR reflecting films that don't actually give any real tint; check out K Glass which uses this in reverse to make home glazing more efficient.