heater doesn't always blow hot air

[dondiesel444]

OK here's a new problem for me to try and fix on the wife's X. At first I thought it was her imagination, but I have experienced it. The heater doesn't always blow hot air. Sometimes she can drive to work, about 20 miles, leave it on full blast, and it won't get hot, a little warm thats all. But sometimes it will blow hot like it should and burn my hand. I have checked the anti-freeze, the resivior tank is full. I don't see any leaks, the only thing I can think of is maybe there is a restriction somwhere?? Any ideas of what I should check, is this a common X problem, hopefully with an easy fix?? Thanks in advance guys.

 

[Robb]

Sounds to me like your heater control valve may be sticking sometimes. It is the valve that contols how much water flows through your heater core.

Where exactly it is or how to locate it exactly on an X, I am unsure of. Never had to look at one. I am sure someone else here can easily tell you.

Robb

 

[VOATMJ1]

Your thermostat could be malfunctioning as well. Check the temp gage the next time it blows luke warm and then check it when it is burning your hand. If it reads the same temp each time, then you can rule out the stat.

 

[dondiesel444]

thanks guys, I will keep an eye on the thermostat, we are going out tonight so I will check it then.

can anyone else tell me how to check my heater control valve??

 

[Opera House]

Maybe blend door

Mine acted funny for about six months. I thought I was imagining things too. I have strong doubts about those other possible problems. Search blend door. I posted "Blend door, so you're cold, cheap and lazy." Cutting a hole is the only way to know if you have the problem. Mine still moves sometimes on its own power even though it is cracked at the actuator.

 

[Ky-Judge]

My '94 EB has a water control valve that is malfunctioning. It is in the line where the heater lines go thru rhe firewall and it has a vacuum line attached to it, what i did was unhook the vacuum line and plug it off in the winter and in the spring i hook it back up so that no hot water flows into the heater core. Try this and see if it works for you before buying a new water control valve.

 

[RTStork]

Are you losing any coolant? A bad heater core can cause your "no heat" problem. A bad head gasket can also.

 

[dondiesel444]

I think I fixed THIS problem, I hope. I took of the vaccum line to heater control valve, then pushed it on, it was loose. Either that or the valve is sticking. The heat worked good all day I had the X, my wife took my truck to work so I could wrok on the mysterious self-unlocking door problem. I am not loosing coolant, I think it was a slight vaccum leak or the valve is sticking a bit. Thanks for the help guys!!

 

[daniel cauchon]

you might as well change the heater control valve cause they are not very good ! all plastic and leak is the favourite passtime !! it takes 10 minutes to do and very easy and cheap too...over here in Canada it`s 40$ . I just change mine and it`s great since then.