Hey. I have a problem. I can't stop heat from blowing into my car. I have all the controls turned off and it still blows heat. It's a 1990 740 volvo gl wagon. Since the air doesn't work right now this is not a good problem. Any ideas?

 

Your problem is the heater valve. Mine had the same problem. Sometimes when they get old there is a rubber piece in there that wears out. It is located next to the drivers right foot behind that plastic pannel (at least on my 240 it is yours might be in a different place). You should be able to go down to the junkyard and pick up a new one for 5 bucks. They are kind of a pian to take out (make sure you unhook the heater hoses from the other side of the firewall before you take the one out of your car or you'll end up with antifreeze all over your floor)

 

Yeah, your problem is the heater valve,sometimes it also has the potential to create a lot of heat.And while having a high temperature within the engine makes it efficient, heat can build up over time if left unchecked and can possibly result to overheating problems. And when the engine overheats, it makes the engine detonate and lose power under load, damaging various engine parts such as pistons and rod bearings in the process. Same with my volvo 240 radiator.