Heater Does Not Work. Intermittent

[Degsy]

Guys,

Having a problem with the heater on my corolla 2003 E12.

Most of the time it takes quite some time to get hot. Recently on my commute to work I drove 60 miles without the heater getting hot. The engine was hot but not the heater.

Other times it heats up as soon as the engine is warm.

The fan works, I've took the centre console off and the wires are still connected to the dials.

I'm not sure what else to check.

Any suggestions appreciated.

Degsy

[oldcodger]

Hey,

Its a regular problem, was featured a few days ago, just look back on the recent posts, there is a link to a very detailed thread of cleaning out the heater matrix.

My link

[Degsy]

Thanks OldCodger. I am currently reading the post you gave me and the other ones linked to them. good info.

one question though. If I had a blocked heater matrix would that not make the hot air permanently cooler?

the problem I have is the length of time it take to heat up to max temperature varies considerably but when it does heat up its very hot. if the heater matrix was blocked wouldnt it never heat up to max?

[oldcodger]

Thanks OldCodger. I am currently reading the post you gave me and the other ones linked to them. good info.

one question though. If I had a blocked heater matrix would that not make the hot air permanently cooler?

the problem I have is the length of time it take to heat up to max temperature varies considerably but when it does heat up its very hot. if the heater matrix was blocked wouldnt it never heat up to max?

Hey,

Two things come to mind;-

It could be a partial blockage thats on the verge of totally blocking then just managing to clear enough to let it feel hot.

The other, the heater flow control valve is sticking /faulty giving similar symptoms.

Assume theres little chance of the rubber pipes to the heater being kinked ?

Assume the engine gets up to proper temp in the normal few mins - ie main stat not faulty.

The book says , when the engine is hot, feel down by the bulkhead the two hoses going to the heater, they both should be hot when the control valve is on hot.

hth