High temps inside car
 

The car is a 67 Tempest 4 door hardop. Every time I drive it, it gets really hot inside the car. The vent/heat doesnt work (yet) so I doubt the heater is stuck on.

According to my Sunpro gauge pack, the engine runs anywhere between 195 and 210 depending on outside temp and driving conditions. It doesnt seem to have any impact on inside temps.

Does anyone have any ideas why its so hot inside the car? Was the factory insulation decent? Could it have broken down over time?

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Add a shut off valve to the heater core.

I was just under the dash replacing the neutral safety switch (column shift auto trans). The steering column where it passes through the firewall was hot. I wonder if the driver side exhaust manifold is heating up the steering column tube?

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Do you have the firewall insulation installed? Are there any open holes in the firewall that would allow heat to enter the passenger compartment? Any kind of insulation installed under the carpet?

The factory firewall insulator is still there and the under-carpet insulation is still there, too. I haven't seen any holes on the firewall yet.

Right after i got home from work last night I took a temp reading of the steering column tube where it comes through the firewall. It was 140⁰!!!! I think the heat is coming from the drive side exhaust manifold.

What should exhaust manifold temps be for a stock engine?

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Exhaust manifolds will get up over 400-500 degrees. Normal. I've been driving first-gen A bodies for over 40 years and have never had your issue. Is your manifold TOUCHING your steering column? Where else is heat coming in? Did you check the heater box? My bet is your heater is stuck on. These cars don't get very hot inside unless it's the middle of summer.

Try the fix that chrisp mentioned. Cut the hot water to the heater core is a start.The rubber on your dampers in the heater housing might be toast. If your in Socal that heat could cook any soft parts. My rag top came from there. Anything that was soft is now petrified.

The steering shaft is not touching the exhaust. There seems to be plenty of room.

I took a quick look at the seals/grommets on the firewall. The speedo cable grommet is missing. Everything else seems like it's there. (But every piece of rubber under the hood is cracked so maybe they are still letting in heat??) I have a replacement speedo cable grommet for a Grand Prix that may work. I'm going to try to get that in tonight.

I will also bypass the heater core tonight and see if that makes any difference. https://uploads.tapatalk-cdn.com/202...f99157b3ac.jpg

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Tried bypassing the heater core and installing the speedo cable grommet. It didnt work. The steering shaft tube/steering column is still 140⁰ where it passes through the firewall.https://uploads.tapatalk-cdn.com/202...08eea748f9.jpg

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Bypassing the heater core will not help with the steering column heat, but maybe with the overall heat in the passenger compartment....did you test to see how hot the interior got with the heater core bypassed?

140 degrees probably is not that bad, I am willing to bet that my headers are producing a much higher heat load into the firewall than your manifolds, but I have never checked it as you are.

Can you peel back the carpet and take some more measurements? Maybe the heat is coming through the firewall/floor from entire exhaust system? In that case maybe all you need is some more insulation material installed under the carpet.

With the heater core bypassed, run the blower motor on HEAT to move air.
 

Do the kick panel vents work? If the car is moving, the kick panel vents are open, the windows are down and the vent windows are open all the way, it's usually windy inside but bearable.

These years can get pretty hot inside if the air is stagnant.

Sometimes just moving air around will help. If you blow some extra air past your feet with the heater - with no hot water in the core - it may help.

But, in all honestly, I've never used a temp gun on a steering column, so 140* might be normal.....

Its an AC car, so no fresh air vents in the kick panels. The vent doesnt work yet, either (one of the things on my list to fix). The only relief is with all the windows down and the vent windows turned so air is directed toward my lap.

I've driven old cars forever and have never felt this much heat coming from the firewall and floors.



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The a/c system requires vacuum to close and open certain doors internal to the air box. Without sorting that out, one of the previous answers was to stop the flow of hot coolant to the heater core. That would be your easiest effort, and will probably part of the problem.

I blocked it off. There was not any noticeable difference. I am planning on replacing carpet soon, and will replace insulation while I have everything apart.

In the meantime, it's still hot!

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I'd highly consider adding a thermal barrier while you're doing that work. The factory style insulation helps, but there are modern products these days that are more effective.