Heaters And Coolant

[Dan-the-man]

Just bought an 02 rolla t sport and the heaters are lukewarm, both pipes to the heaters matrix are hot.

Looked at the coolant, it's on Min and is green. So I'm assuming to remove the heater matrix pipes and flush with hose and to change the coolant for Toyota red? Is there a guide to do a complete flush?

[oldcodger]

If you search this forum you will find a couple of big threads on this same problem.

Seems cars around your age do suffer from blocked heater elements and hopefully flushing will clear them.

Those threads details what folk have used and how they have done it.

As yours already has been changed onto non Toyota antifreeze, wonder if there is now any advantage is using T Red ? though expensive.

Think the important thing is to flush out any old antifreeze and whatever you buy, ensure you use only deionised water * to dilute it with if a concentrate.

* £1 a 2ltr bottle in the food supermarkets.

[Dan-the-man]

Right, I've flushed the matrix and the system and changed to t red and the heaters are still cold, both the matrix pipes are red hot so could it be either an air pocket in the matrix? Or is there some kind of control flap to direct air through the matrix? And if so is there a guide or how do I get to it?

[TomdeGuerre]

If both the matrix pipes are red hot then you don't have any problem with an airlock. If the system was airlocked you would not get both pips red hot. I think you have a problem with the heater control flaps inside the heater box. Another possibility is that the heater matrix has somehow moved, allowing incoming cold air to by pass the matrix.

BTW does your heater fan work all right?

[oldcodger]

Assume it flushed though the matrix ok, so if it was filled with water would think it would have run though ok.

Did you squeeze the bottom hose has you filled up with antifreeze ? it helps clear any air locks.

Can take a good run out to purge out any remaining air pockets, as you will then find the reservoir level will have dropped a little.

Does your model have heater Rotary dials or Electronic controls.

The Rotary ones have a cable running to the air damper flap which mixes the heater with the air.

The Electronic one will need a motor and thermistor to operate so more complex to check.

Unlike older cars there does not seem to be an actual control valve on the hot water pipes.

The Haynes 2002-2006 standard rolla manual shows how to get to the rotary cable controlled flap, but not how to get it out, think that might be a major job.

Assume it is blowing air out ok and the pollen filter not blocked.

The rest of the waterworks running ok ? coming up to temp ok and the thermostat seems to be working ok ?

This video might help, goto about 8 mins in.

https://www.youtube.com/watch?v=-XjXTVJhFLM

As he says, if you turn the heat control from min to max , I can hear a dull thud and the flap closes to its new position.

[Dan-the-man]

Yeah when I changed the coolant, I ran the car until it was fully up to temp with the rad cap off while squeezing the pipe.

Also drive the car round for a few days and I've topped the level up so there shouldn't be any air locks in the system.

It's a t sport so it has the electronic heaters, sometimes when I turn it to HOT it gets slightly warm and then goes back cold again.

[Dan-the-man]

The fans work fine and the cars temp gets up halfway and stays there so I think the thermostat should be ok

[oldcodger]

It sounds like all the plumbing is working ok then.

If you set the fan on to just 2 bars, and the mode to bottom and middle, then run the temp control from H to L or L to H, you should hear a quiet but definate whoosh/thud as the delefector flap moves across; it does on mine.

[Dan-the-man]

I can hear a buzzing sound when turning the temperature to 20 degrees coming from behind the dash. So hopefully help me locate it to make sure it's working

[oldcodger]

Hard to say what the buzzing sound is from such a verbal description, one of those things you need to hear yourself.

Assuming its totally different from the blower and coincides with the changing of the temp setting and it goes off when you lower the temp ( or increase, whichever way it happens) then it might be the motor/servo thats trying to turn the flap.

Could be a faulty servo which looks like its a bolt on part , without too much disassembly of the dash/console or that the flap itself is jammed; if you have to go inside the unit then think thats a major job.

As for getting at those units, no experience and not seen anything covering the electronic version like ours....

Think my first line of attack , before disassembling the dash, would be to try and disconnect the servo or its fuse and see if that stops the buzzing, if so, then it confirms the servo or flap are likely the problem.

The pics might help though your model might be a bit different.

Looks like you might be able to see /get to the servo from under the dash near the pollen filter /blower ...?

[TomdeGuerre]

I meant to post this link about the problem someone experienced with broken teeth on the cog of the flap drive motor. Might also be relevant to your Corolla, Daniel?

http://www.toyotaownersclub.com/forums/topic/140437-auris-climate-control-not-blowing-on-windscreenfeet/