I am trying to resolve the heat problem in my 75. I was looking through some old threads and I saw that Koolmat was reccomended to deal with the heat problems. It looks like a good product, my only questions are, is this still the best way to resolve the problem, and secondly does it go under your carpet, or get installed under the car? I would hate to have to mess with the carpeting in my car.

Thanks!

 

Could wrap the exhaust. My headers are wrapped and they stay cool.

 

Does that help much with interior heat? The passenger compartment is what I am concerned about. I noticed on the passenger side, there is a lot of hot air blowing into the compartment, and you get the engine smell, even though the heater and AC are all turned off. I was wondering if that could be a ducting problem? It's quite a bit of hot air.

 

There are so many reasons why you can have hot air coming in. To reduce the source of that heat wrap your exhaust like Norval said. To stop the air coming in you need to do some research into "where" it is entering the cockpit ie:

1. Through vent - heater core not shut off - add a valve to shut it off
2. Carpet plugs missing in firewall - replace
3. Cracked caulking/glue around firewall vent join - seal up
4. Bad seal on your vent seals for outside air
5. Holes/cracks in cold air chamber to engine bay interface - seal up, add new hood seal, put plugs back in holes.
6. Missing collar on gearbox, missing "foam" seals on framerail, missing heatshields on firewall.

There are many sources you need to get under the dash when the engine is running and track them down one by one. There are also several other forumites who solved these problems. Do a search on google for heat problems in corvettes or look under corvettefaq.com

 

Thanks, very helpful!

 

Ludicrous,
Welcome to the Forum! On my 1974 L48 auto, I found that a lot of hot air was coming thru the shifter hole. IF your car is an AUTOMATIC, you will find that the shifter does not connect to the trans though the hole in the floor, but via a cable that goes thru another hole, but the factory installed a rubber boot about 1 mm. thick (or THIN!!!) to fill the gap. After 30 odd years, the rubber goes hard and cracks, letting the hot air from the exhaust etc, up into the car. The standard shifter DOES sit lower than the floor to which it is mounted, which is why the boot was fitted, I guess. I looked at the price of a replacement rubber boot from the US and it seemed bloody expensive, so decided to build something better myself.

I built a (male) buck out of MDF and body filler and made a (female) mould out of fibreglass to replicate the rubber boot. Then, using two or three layers of fibreglass mat, I made the finished item out of the mould and fitted it in the hole in the trans tunnel after gluing some insulation on the underside. I used the factory metal hold down trim and factory screws to secure it. Once the console goes on, you can't see it and it HAS to work better than thin rubber (for insulation). It would also kill some of the noise, too.

You could build this yourself if you're handy with tools and if you have no access to fibreglass, a local boat builder etc. should be able to help.

Hope this helps.

Regards from Down Under

aussiejohn

 

ludicrous, while driving my 73 up to wisconsin my daughter said how her right foot was hot, since i already went thru my vaccume system a few weeks before, i switched on the a/c(which closes the flapper in the wiper well ,, and opens the passenger kick panel damper,, allowing a/c to recirculate the cabin air) once i turned on the a/c she didnt feel the hot air at her right foot anymore----so whats happing here is,,, theres a gasket that runs along the top of the hood,, that gasket(or weatherstripping)is supposed to keep hot engine air from entering the wiper well-- which if it gets in there,, will be pulled in by the fan(when the a/c is not on) and thrown right in the cockpit--- take it for a ride with a passenger and try that---also you can see these 2 acuators working by looking in the wiper well for the fresh air damper and you'll have to take the passenger kick panel off to see the one in there--- then turn on the a/c--- when you turn it on, the one in the wiper well closes ,and the pass kick panel damper opens--- so the air is being drawn in from the cabin up to the a/c and cooled and back in thru the vents--(a red flag popped in my head when you said you smelled engine-)----carl

 

Insulation under the carpet helps quite a bit, but I found that a shut off on the line to the heater core really helped. If you search you will find a lot of discussion about one valve on the supply line, or a valve on both lines, I used one and it has been fine for over two years.

 

This sounds a lot like what may be going on, when I have my wife driving I notice there is quite a bit of hot air coming in by my right foot.
I also notice that when I turn on the AC or the heater or anything, I don't get much air coming out of the vents by the wiper controls, and none by the lower vents, but the AC does work because when it is on the air coming out, what little there is, is cold. Could there be a problem with the ducting in general causing hot engine air to blow into the compartment, and also cause weak performance from the climate system?

Thanks for the help though, this gives me something to look for!