Interior heat

[Nitrate]

1981. 2000. My heater valve cuts off the heat, but the cabin still gets too hot. Where is the majority of the heat generated? Block, exhaust, cooling, transmission? I'm trying to insulate at the major source of the heat. Any opinions on this? RB

[Odoyle]

Check if the insulation is still intact underneath the shifter boot and panel, mine was destroyed and pouring heat into the cabin. Such a difference after it was sorted.

[Nitrate]

Yes I replaced all of that with new parts and added additional heat blocking material.. Even made a rubber gasket to seal the mounting plate on the top of the transmission, and encapsulated the entire transmission hump with heat block/soundproofing material. I've had other sports car, none were what you would call cool, but this Fiat seems to take the cake. I'd like to get some opinions on where most of the heat is generated so I can isolate that area. I have noticed that the metal portion of the gearshift gets very hot to the touch during extended freeway speeds. Trans fluid is new and at the proper level. RB

[81SPIDERMATT]

I think that there is a heat shield over the cat that sometimes rusts away or is deleted for whatever reason

[DieselSpider]

Usual culprits are where seals have deteriorated where things pass through the firewall and where the shift lever and ebrake linkage comes up through the transmission tunnel. Under carpet insulation could be missing in the upper part of the foot wells too.

Catalytic converter heat shield could also be missing but that would be more localized on the passenger side.

[spider2081]

On my 81 a lot of heat comes through the area where the emergency brake lever and heat controls are. Not being sure hoe to insulate the area I cover it with a couple of small cloth towels. This makes a big difference on hot days.

[Ragno124]

With the water valve closed and the vent open full, you should feel cool air on your feet when you drive at speed. Are you at least getting this? If hot air is still coming through vent, then your water valve is not closed and could be the source of the extra heat in the cabin.