Car Interior Heating Up - Urgent Problem to be Resolved

I have a 1986 cutlass supreme brougham.

When I drive my car, the car's interior continues to heat up. Even if the heating is switched off, the central raised portion (under which the gear differential is located) continues to eb heated and hot air air continues to blow in from under the center bottom of dashboard (right behind the ashtray/cassette deck).

Could someone help me solve this heatign problem? How do I close this blowing in of hot air?

THANKS!!

hey,very simple problem I think,your air mix door(blend door)stuck open.It suppose to redirect air from heater core.Basicaly this door directs air flow through heater core or bypasses it.I don't know if yours is controled by cables or vacuum,so start cheking under dash for binding or broken cables or disconected or broken vacuum lines.hopefully this helps and good luck

Check the hot water control valve and make sure that shuts off as well..

I have a '77 Olds Delta 88 Royale 4-door that has the same problem. The car is already an oven with wheels thanks to all of it's carpet, so the fact that it blows air through the bottom vents doesn't help AT ALL. I checked underneath the dash and it turns out that all of my vents are vacuum-powered, but all visible doors open and close properly. Can anybody give me a little more detailed instructions as to what I can do to fix my land yacht? Thanks in advance for any help.

If you're saying that the air blows only through the floor vent (heater) then I'd check the vacuum feed like from the engine into the dash. Those break a lot, I've had it happen several times on different cars. If I'm not mistaken, you'll find a vacuum line connected to a globe shaped vacuum chamber that is connected to the control switch on the dash. Make sure that vacuum is getting to that globe. Then make sure the line out of the chamber is intact and connected to the dash switch. The switch is controlled by a sliding lever that you move to either vent, air, heat or defrost. This directs vacuum to the correct vacuum motor that opens and closes the various doors. Sometimes they fail, I've replaced one or two. It's a PITA job pulling that stuff out, but if the switch or router if you like is defective, you need a new one. You should also have a vacuum controlled heat valve that is under the hood and allows hot water to enter the heater core. This valve sometimes leaks and people simply put a piece of pipe or just run a heater hose from the block to the heater core. That has hot engine coolant in the heater core at all times. Great in the Winter, sucks in Summer. If the valve was removed, spend a couple bucks and get one. It's vacuum controlled by the temp sliding switch in the dash. When you increase the temp on the switch, it allows hot water to enter the core. When you set it on cold, it doesn't allow hot water in.

Well, I went ahead and inspected my car just a little bit more, and when I turn the key to the 'on' position without starting the engine, I can hear a secondary blower motor somewhere behind the dash which seems to be providing the air movement underneath my dash. This secondary motor doesn't <span style="font-weight: bold">SEEM</span> to have any relationship with the primary blower motor or the controls for it (IE when I shut off the primary the secondary keeps goin,) and I don't have a clue as to how I can shut it off. Any ideas?

It's designed so that the blower motor starts whenever the ignition switch is in "ON". No way to stop it completely. The blower switch doesn't have an "OFF" position.

This primary/secondary blower thing is throwing me. Some early 70s cars had an optional high-level power ventilation system with blowers in the ductwork to the dash vents, but I've never heard of it past the 1972 model year.

Ok, well, I don't believe it has two motors, just the fact that the one is always running throws me off, I know that it's directly related to the A/C system some way though. If I were to recharge my A/C and get it to work after retrofitting it to R134-A, would it cool off then?

Yes it should. Do your dash vents blow outside air? Can you direct air to the defogger, vents and floor? If all that is working, then all you need do is get the A/C fixed. Make sure the hot water valve is functioning, this will keep hot water out of the heater core when you're trying to cool the interior of the car.

Ok, sorry to sound like an idiot but I'm new to Chevrolet engines (350), how would I check to make sure the hot water control valve is functioning properly?

OH, that reminds me, one thing I noticed is that you can occasionally hear water gurgling in the cars plumbing somewhere...

The easiest way to find the hot water valve is the trace the two heater hoses back from the core to the engine. One of them will have a valve in it, you can't miss this thing as it's fairly large. It should be the spliced into the hose that runs from the water pump to the heater core. This valve will have a vacuum line on it that actuates it. It should allow hot water to circulate through the core when the heater is on (when you set the temp at hot or in the red zone on your climate control panel). When the climate control is in the cold or blue area, it should prevent hot water from entering the core. One way to check is to see if the hose between the valve and the core is hot when then the engine has warmed up and you have the temp control set at cold.

Sometimes these valves fail and people cheap out the repair by simply removing it and putting a piece of pipe or tubing in it's place thus allowing hot water to continually circulate. Other times, they just put a hose from the pump to the core and one returning back to the blcck which allows hot water to run through the core continually. See if that's the case by tracing the two hoses from the core to the engine. Let us know what you find and we'll go from there.

Alright, I just checked the car again, and as far as controlling the interior vents, they all seem to function properly. Now, I did as you said and I fired up the car and turned my climate control down to as cool as possible, and then felt the hoses both coming and going from the heater core to the block. They were both VERY hot. I put the climate control on hot, and they were still hot, but no hotter. The only vacuum-controlled device I see is mounted directly off of the block going to the heater core, so I'm assuming that's the hot water control valve? Anyway, that's what I found out, sounds like that valve's broken... Anyway, thanks.