Howdy y’all. Hope everyone is having a great day.
New Corvette owner here, I purchased a 72 T-top in Ontario orange as a 20th anniversary present for the wife, I knew from the state, that a 50 year old car was already going to be a project car when I purchased it. Just didn’t know how much of one it would be.
But this thing has something seriously wrong with the amount of heat it is generating, the passenger compartment gets unbearable with the windows up, and enough heat is coming from somewhere, that the shifter boot, melted from its base mount and popped up onto the stick. I know she isn’t running the engine hard, but even if she were, it shouldn’t be that bad.
Does anyone have any suggestions? I fear it somehow getting hot enough to catch fire and that being the end of her 20th anniversary present.

As is, when we got it, the entire parking brake assembly had been removed. I need to find a way to reinstall that someday, but working on it from a wheelchair is a little bit difficult, especially when it comes to climbing under it, while at the same time, getting it worked on by a mechanic is also extremely difficult, due to an extremely tight budget.

Any advice or suggestions would be greatly appreciated.

Keep safe
Razor

 

I can just about guarantee your heater is on regardless of what the HVAC selector is indicating.
Very common with these C3s. The poor A/C is constantly fighting the heater.

The heater core is operated by a vacuumed controlled valve located near starter. Hot water from the engine is constantly circulating through the core.
You have to shut that flow off.

Of all the vacuum operated. accessories (and there are a lot) that valve fails 90% of the time. All GM had to do was run a steel cable over to the valve from the dash.
That worked well on Chevelles, Impalas, trucks, Novas, etc.

You have three options:
Buy a new valve replacement and hope you have enough vacuum to operate it.

Completely by-pass the heater core by purchasing an adaptor that splices the heater hoses together near the firewall. Realize you will never have heat for defog / defrost.

Or, purchase a shut-off valve (NAPA) that controls the coolant flow. They have a threaded handle much like a petcock and you close off the hot coolant supply in the spring, open it in the fall. Last I looked the valve was around $28 and is available in either 5/8 inch or 3/4 inch.
This option allows you to omit the original valve and adjust your temp / coolant flow manually. Which is very easy.
Depending on your regional weather, you may never even touch the valve or seldom.

 

Here ya go...glance thru the replies...any problem you have can be corrected.

• CorvetteForum - Chevrolet Corvette Forum Discussion
• C3 Corvettes, 1968 - 1982
• C3 General

• Interior Heat

 

Check if you have a collar in place..post 53..
https://www.corvetteforum.com/forums...79-w-ac-3.html
stops most heat coming up shifter..to melt it though? Not sure..pics of exhaust etc? I also agree with above, put in shut off valves.

i would also prioritize the e brake

 

I can't speak to the coolant stuff but when I did the LS swap into my 71 C3 before I installed the engine and trans in the trans tunnel I cleaned it down to the bare fiberglass and installed DEI insulation. Kind of shiny waffle looking stuff with fiberglass insulation. Self sticking.
Then on the interior prior installing the new carpet I lined the whole car with dyna mat "like" stuff and then double faced foil insulation mat. All from DEI. Then the carpet.

 

I've had the trans tunnel get pretty warm on long drives, but not so much that it causes damage. Melting the shift boot is not normal.
Any way to post pics of the underside from engine to differential?
Do you have headers or other modified exhaust?
What is the engine's operating temp?

 

Also check the firewall for any missing or rotted grommets.
I placed a couple of bright lights under the hood, closed it, disconnected the battery, turned out the garage lights, opened the car doors and looked around under the dash, looked like a disco ball with all the pin hole light beams.
Also recommend the foam collar over the transmission.

 

Gotta say, melting the shifter boot! HOLY S... Batman!
something is definitely not right here!

 

In my '69 Camaro the tape in the cassette player would melt if the player wasn't being used!
That's when I bypassed all the 195*f underhood swithces and installed a 180* thermostat/deleted the EGR and blocked off the crossover .

 

What is your timing set to?

 

Hi Razor, welcome,
I won't comment on the heat issue, There are a lot more people chiming with excellent advise. I would not add anything new. You mentioned you're in a wheelchair, if you want to work on your car, you may want to consider a Maxjax. There is a guy on Youtube with a C5, he reviewed his maxjax after 5 years of use. He sits in a chair to work under the car. He is also on this forum Toys4life C5. I've linked the review on YouTube.

 

Me = 12°+

OP = ?

gm sent out a notification not to leave tape in player when not in use.

 

Thank you for the info, I need to go through and rebuild/repair all of the vac system under the dash as is. Did under the hood last year and have a few just hanging through the firewall due to wrists not being noodles. I swear, they don’t make it easy to replace those lines and reconnect them.

 

Sorry for the image being so large, it would not let me shrink it down on my device. Yeah she is dirty, but is pretty much like we got her. My wife only drove it 4 or 5 times before stopping due to the heating issues. Here is the melted boot that popped up while I was riding with her.and yes, it had looked perfect before she began driving it.

 

Problem solved........the insulation also solved the noise problems from the engine bay and from the tire/road noise






I also applied a layer to the INNER door skin which helped even more with noise issues.
The door without insulation actually acts like a cheap speaker sending road noise into the interior.

 

Above pic looks similar to my 71 project.

 

You guys have inspired me to do the extra upgrades that really make the car better to drive.

 

Did anyone mention this underbody transmission tunnel insulation yet?
It is critical to reflect as much heat as possible and not let it get into the car.
A friend told me his was missing and the side of the console inside the car gets uncomfortably hot. Like almost too hot to touch.

 

Between the foam collar, the transmission insulation, and the vacuum controlled hot water shutoff valve, all of my suggestions have been covered, except one. Check your timing. If it is too retarded it will generate excessive heat in the exhaust. I’ve actually seen exhaust manifolds glowing red hot.
Melting the shifter boot is extreme. I suspect you have a combination of some or all these problems.

 

I will be checking the timing when I get to that point as well.

Thank you
Raz