flynhi

After thoroughly insulating my floorboards and replacing flex boots, I still have too much heat at the driver's feet.

Any ideas as to where I should look for the engine bay heat that is sneaking in?

1979toy

1. There should be a collar around the top half of the transmission bellhousing. If you don't have it hot air gets in at the shifter hole and forward through the console.

2. If you don't have your hood seal the hot air exits from the rear of the hood and gets in your vent system at the base of the windshield.

3. Sometimes those pesky heater shutoff valves leak. A second on on the return side might help.

vettfixr

Check this old link of mine. I think it may be your problem. http://forums.corvetteforum.com/zero...732679#3732679

flynhi

vettfixr -
I have checked your idea and it seems OK. Air temp from my upper dash outlets is near ambient when in Vent position.

I'm wondering if there is an opening in the outer steering column tube that could be allowing engine bay heat nto the cockpit. Any thoughts on this?

vettfixr

One other place you might want to look is the shifter boot. Not the top one but the one that seals the shifter to the floorboards. I had a tear in mine and the heat coming through it was unbelievable. Also make sure that it's sealed well to the floor with no gaps. The tranny tunnel will channel all the engine heat right into the cockpit if you don't have a good shifter seal and because of the way the cockpit sits on the floor the only place for the heat to come out is by your feet.

flynhi

vettfixr -
Right you are. I replaced both boots recently.

cardo0

:skep: Here’s one trick. Use a light at night inside the people compartment to look for light/leaks on the other side of firewall (or try a light in the engine compartment too). Lit up holes are indication of hot engine compartment air leaking in. Yes there is a gasket on the column and it’s a job and a half to replace. But the column mount/bracket covers the hole up pretty much.
Also upon replacement of heater core discovered every single gasket missing inside heater box (Bubbas been there) – even ventilation/AC was mixing with engine compartment & heater core air.
Now my ’74 has metal (aluminum?) heat shields installed on the front/engine side of floor pans. Does yours? Currently installing exhaust pipes from my new Thorley headers to the trans cross member. Noticed a 2”x3” heat damaged spot on the passenger side floor pan. Repaired with one layer of glass. Bought some 12”x12” adhesive backed heat shielding from Cool It and trimmed to fit. Installed using Hi-Temp RTV on edges for good measure. Next step is to wrap the exhaust pipes with header wrap where they go by the floor pans.
:yesnod:

flynhi

Cadro0 - I tired your light trick and found a 3/32 sq hole near the steering column that I think was the culprit. I'll know tomorrow.

Thanks for the tip.

Enad

Some very good ideas here. I am not sure if it applies to your year but... Inside the heater box is a flapper that is controlled by the sliding Hot/Cold switch. On mine when moved all the way to cold it did not close the flapper completely. Hence heat came in the ducting all the time the car was warm.

Dane