Toyota starlet heater problem

[Ruddock984]

Hi all,

I have a 1996 Toyota starlet ep91 and the heater does not work. the heater only blows cold air, don't think it is the blower motor or the blower resistor as all fan speeds work. The two pipes which go from the engine through the firewall into the car are both hot which I think means that the heating system is working at the engine side. So my question is, is there and blend door actuators which allow the heat to work.

 

[Jay]

There's nothing else I can think of other than a blocked up matrix core unfortunately. If you can get a hand to the core inside the heater box that should confirm if this is the case but it's a bit of a dig to get a paw in there.

When you operate the temp adjustment you can heard the main heater box flap move okay yes?

 

[Ruddock984]

if the matrix was clogged up, would there be a temp difference in the two pipes coming out of the firewall, I read that if one pipe is cold and one is hot then the core could be clogged.. is it possible to flush out the heater core with water to unclog it. I suppose there is no blend door actuator which allows the hot air to flow has failed. I haven't checked the noise of the heater box flap but will tonight.

 

[Jay]

Those two pipes enter the matrix at the top so if the core is clogged the flow doesn't reach it. Bit of a design flaw tbh.

You can disconnect both pipes at the bulkhead and blast a hose into them. Flush and reverse flush until the water runs clean. Hopefully it should help a little.

Winter isn't fun when your heating isn't working!

 

[Ruddock984]

Thanks I'll give that a try
Just to make sure, is there a heater control valve on this car

 

[Jay]

The standard heater has a cable that goes from the heater controls to the bottom of the heater box, this moves the main flap in the box to direct airflow either through the matrix (hot air) or past it (cold air). The matrix is always hot.

If yours has climate control the main flap is electrically operated by motors on the heater box instead.

Hope that makes sense,

Jay

 

[Ruddock984]

Give the heater core a flush and lo and behold gunk and crud came flowing out and the heat is working

 

[Jay]

They hold a fair bit of crap in there for all the size of them!

I'd heard of people flushing them with dishwasher tablets but it's a bit cowboy for my liking. Least you won't freeze now the frost is here