Heat from center tunnel at front bulkhead wall, under dash

[rjm98119]

Not really a "problem", per se, but a curiosity... what lines (or what I assume to be coolant lines) are running up through the center of the car, near the center firewall, that would put off a ton of heat, even when the heater valves are closed (because the heater isn't on)?

The other day, I reached down beneath the dash while cruising because I felt warm air across my legs. Touched an exposed part of the metal floor/chassis, the raised spot (tunnel?), under the dash, in front of the little storage bin area, against the front bulkhead wall,... and it was FRICKEN HOT. Not hot enought to burn, but like legit HOT... at highway speed on a 69 degree day in the evening. There's a lot of heat being dumped into the cabin from there.

I always puzzled why the cabin get so darn hot when just sitting there on a modest day, when I couldn't really detect heat from the rear, nor being blown in from under the car (though that DOES happen at times). It didn't occur to me that lines to the radiators might be running through that area [what I would guess to be an uninsulated area]. to transmit such heat directly into the cabin.

The other question would be... anyone try to insulate it?

 

[Milk242]

I thought the coolant lines are running along the sides of the car.

 

[ffre92]

Not really a "problem", per se, but a curiosity... what lines (or what I assume to be coolant lines) are running up through the center of the car, near the center firewall, that would put off a ton of heat, even when the heater valves are closed (because the heater isn't on)?

The other day, I reached down beneath the dash while cruising because I felt warm air across my legs. Touched an exposed part of the metal floor/chassis, the raised spot (tunnel?), under the dash, in front of the little storage bin area, against the front bulkhead wall,... and it was FRICKEN HOT. Not hot enought to burn, but like legit HOT... at highway speed on a 69 degree day in the evening. There's a lot of heat being dumped into the cabin from there.

I always puzzled why the cabin get so darn hot when just sitting there on a modest day, when I couldn't really detect heat from the rear, nor being blown in from under the car (though that DOES happen at times). It didn't occur to me that lines to the radiators might be running through that area [what I would guess to be an uninsulated area]. to transmit such heat directly into the cabin.

The other question would be... anyone try to insulate it?

I suspect that this heat is likely the cause of various rattles in my car. A dash rattle and clutch pedal creaking sound only show up after driving the car more than 30min. I’m assuming it must be from heat expansion from cooling lines.

 

[geoffbland]

I thought the coolant lines are running along the sides of the car.

The main engine colling ones go along the sides, as well as the inter/charge cooler ones. But there's all kinds of lines in the front of the car going across the subframe and to the heater box and of course the radiator itself is hot.