Problem with heat in the cab

[da_raabi]

I am curious if anyone out there with no floor insulation is having trouble with heat coming into the cab. I only have a cab-width rubber-bottom floor mat up front and the heat that comes through the tunnel is ridiculous. When I wear my Ostrich boots my feat actually feel like they are burning. Is this normal for one of these trucks with no floor insulation? Could the tranny be overheating? Maybe its the exhaust? Its not like I have headers or anything, although it is a big block so lots of heat there. I just dont want to put a bunch of insulation down and cover up some other problem. I just dont remember it being this bad when I first pulled the old carpet out...

 

[firebane]

LOL its normal. I currently don't have my shift boot for my transfer case and the hole for it is like a vacuum for air and sucks a lot of hair up.

You have an engine, transmission, and exhaust all in close proximity to that location so yes it gets warm.

 

[mistaake]

Back when I had my 1983 C20 with the 350 V8 I do remember that there was some heat that was coming through the floor/trans tunnel.

Definitely more than I've had with any newer vehicle but not to the point at which it was annoying or worth thinking about.

Maybe your cat is clogged or some exhaust restriction or something??

 

[DoubleDingo]

Yep with no insulation or anything to block it, the floorboards get toasty. Another thing that adds to the heat in the cab is the heater core. This year I bought some nipples to bypass the heater core during the summer and that helped some for mine. But mine has the factory carpeting, so the feet aren't getting hot like you describe.

I remember Mean Green back in the 80's after grandpa passed away. I don't know if he bought the truck with the center hump cut out, or if he cut it out to install the sm420, but the only thing there was a piece of plywood sitting on the transmission shifter snout. You could literally see the ground, the driveline turning, etc. Talk about a hot ****** in the Summertime, and cold in the Wintertime. Took me many years to find a hump, and then another 15 or so to locate a flange that went between the hump and the firewall. After all that and some insulation it was bearable to ride in the truck and no more exhaust getting sucked in through the floor.

 

[MadOgre]

I am curious if anyone out there with no floor insulation is having trouble with heat coming into the cab. I only have a cab-width rubber-bottom floor mat up front and the heat that comes through the tunnel is ridiculous. When I wear my Ostrich boots my feat actually feel like they are burning. Is this normal for one of these trucks with no floor insulation? Could the tranny be overheating? Maybe its the exhaust? Its not like I have headers or anything, although it is a big block so lots of heat there. I just dont want to put a bunch of insulation down and cover up some other problem. I just dont remember it being this bad when I first pulled the old carpet out...

I dunno. I have bare floors and my heater core is functional all year round and I don't feel any heat at all in the summer or winter unless I turn on the heat.

Why not open the fresh air ducts and see if that solves it? But I don't see why it should be that warm unless something is not plumped right. There is quite a bit of spacing between the floor and drive line components. Are your body bushings sagged?

 

[Georgeb]

I also run with no floor covering at all all year. It doesn't get too terribly hot in the truck. I can run with the floor vents pulled open and the rear slider open and I get nice cross flow. Pulling the wing windows open all the way so they scoop adds that lil extra to keep confortable. Of course it also scoops in the ocasional wasp which keeps things interesting!

 

[da_raabi]

Well here are a couple thoughts. The truck still has the original exhaust manifold on it (the ones that look like they have a little accordion in them), but all the emissions stuff has been pulled.

The truck never had cats - its a 1 ton.

Body bushings are decent.

Free-flowing true duals all the way out the back. Somebody even welded a larger pipe over the exhaust to act as a sort-of heat sink all the way along. Neat idea, and it must have taken forever!

Is there some kind of flapper mechanism in the manifold for EGR or something that could be closing things off and/or leaking? I have not looked closely at this, but could it be part of the issue? I just don't remember the truck always being like that last summer.

 

[Georgeb]

How far from the floor are the exhaust pipes?

 

[da_raabi]

How far from the floor are the exhaust pipes?

A couple inches. They are not right up close. Figure factory mounting essentially.

Turns out that flapper I was talking about was for the heat riser. I wonder if its stuck partially shut, not enough to overheat the engine - but enough to create a major heating point right next to my foot. Thoughts?

 

[highdesertrange]

big blocks produce huge amounts of waste heat. especially if driven for hours and hours at a time. add some insulation. highdesertranger

 

[da_raabi]

Yeah I checked the flapper today. It moved freely, and was spring-loaded open. Since there was no vacuum line connected to it I'd have to assume it is always open. I guess my problem is probably just the big block moving around a 6000lb truck like its a sports car. That IS how you are supposed to drive a big block dually, right? ...right?