Heater

Hi,

I have a 2002 Corolla T-Spirit, a few weeks ago, I noticed when setting the heater temp to "HOT" - the temp of the air seems to be more "warm" rather than what it used to be. This model has the digital climate control. I've checked the coolant (previous topics seem to check this first here) - this was not low, but have topped up never the less.

I would really appreciate any suggestions on what I can do / look for next.

Thanks,

Mine's got the same prob too, but it's even more odd, if i direct the fan for forward blow on higher temp it's actually gets hotter

I've suffered this prob before in the past, but can't remember what was wrong with it.

I'm going on holiday soon, so i won't get mine fixed till after then

Happy hunting if you find the prob, otherwise, wait a few weeks and i'll let you know what the garage tells me and how much it will cost.

Bing

Can only talk from my experience but my car had the same prob,the heater matrix was blocked,i only had warm air from the left hand side of the car and luke warm at best from right,i suspect someone put rad weld in before i bought it, independent dealer number one suspect. Good thing about this corolla is that the matrix is handy enough to get out,not a dash out job. A new one is not that cheap to buy from Toyota thou. I think you can get stuff for unblocking it which is what i had done and the heating is really good now.

I have got the same issue with my Rolla but its lukewarm air all round. I checked the inlet/outlet to the heater matrix as i can get to the with the glove compartment out & they are both as hot which doesnot suggest blocked matrix. However i would still like to remove the matrix & give it a clean if possible.

Question: how is it possible to remove the heater matrix without removing the Dash?

On the other hand i am also wondering if it could be the diverter valve not failing to direct the airflow properly over the matrix?

Cheers

Mol V

iv had this on a couple of cars in the past... either the thermostat was stuck open or i had an airlock in the cooling system. ;)

I have got the same issue with my Rolla but its lukewarm air all round. I checked the inlet/outlet to the heater matrix as i can get to the with the glove compartment out & they are both as hot which doesnot suggest blocked matrix. However i would still like to remove the matrix & give it a clean if possible.

Question: how is it possible to remove the heater matrix without removing the Dash?

On the other hand i am also wondering if it could be the diverter valve not failing to direct the airflow properly over the matrix?

Cheers

Mol V

I need to fix this too, you can try to flush the system out by attaching a hose pipe to the inlet and outlet tubes going through the firewall to the heater matrix. Dont use full pressure though as you might blow a hole in the matrix. Personally this didnt work for me, but it might be enough to move the crap out your system.

I'd try anything before paying for a new matrix, fitting would cost a bomb. I also read about a dishwasher tablet trick, put one in the cooling system for a few days and let it work its magic. But theres a little debate as to what effect this will have on rubber gaskets, you will have to change your coolant after naturally. Wouldnt advise doing this, might try myself some time.

Think matrix is a dash out job, how else would you get to it?

I spoke with a toyota expert. No need to remove the Dash mate. All you gotta do is remove the panel under the steering colomn & the matrix is accessible & can even be removed like a card rack after undoing all the fastening points & pipework from there.

As in Post #6 - try and reverse flush the matrix first to see if any crud comes out.

Heater matrix can be removed from the passenger side - take the glovebox out and you will see the metal pipes coming through from

the bulkhead and going onto the heater unit.

Mick

Mine is in Mr T as i type for this exact problem, ill let you know the outcome and cost.

They are also checking out a minor water leak, although no idea where its leaking as no signs, poss Pump.

Update later ...

Ok had call from Mr T and the cause of no heat and minor loss of water is the Water Pump.

Cost is £400 which will be done Monday .......

Will let you know if all is well when i collect Monday evening.

No "LIFT" for me this weekend then i guess ....

Update:

So got Rolla back and early days to tell if water loss problem is sorted, will know this in about a week.

Now for the lack of heat problem, £420, a Water Pump, Thermostat, Drive Belt, Coolant and other bits later and the result so far as i can tell is .................

... BLOODY WELL NONE :ffs:

Needless to say i am P155ed, so shall return this week or at least when they can provide a Courtesy car for me.

Set to 30 or MAX HEAT and its still luke warm.

Will post update.......

Update:

So got Rolla back and early days to tell if water loss problem is sorted, will know this in about a week.

Now for the lack of heat problem, £420, a Water Pump, Thermostat, Drive Belt, Coolant and other bits later and the result so far as i can tell is .................

... !Removed! WELL NONE :ffs:

Needless to say i am P155ed, so shall return this week or at least when they can provide a Courtesy car for me.

Set to 30 or MAX HEAT and its still luke warm.

Will post update.......

That sucks, you should ask for your money back.

I'd have thought though, if your thermostat and water pump had gone you'd have some pretty serious overheating issues! Are they gonna consider the fact it might be your heater matrix now?

At least they fixed the coolant leak problem?

Take it back to them and get them to replace the Heater Matrix FOC (free of charge) - they have not diagnosed the original problem correctly or carried

out an effective repair.

Threaten them with a letter to Toyota GB and a copy to your local Trading Standards Office.

Mick

I know this wont fix it but have you checked the pollen filter aint blocked? That causes bad air circulation and can feel like its not pumping out the usual strength.I know this might not have an effect on actual heat but not been mentioned yet.

Yes it sucks and i will be returning probably tomorrow after work, going to try and keep it civil to start, unless i get no satisfaction.

Water leak fixed ? well i hope so.

I suspect the problem may be the Temp Sensor in the cabin myself, but its not for me to diagnose the problems and pay them at the same time, be surprised if its the Matrix as water, hot water appears to be flowing in and out of the pipes through the bulkhead, way too hot to touch, but if the temp sensor is thinking its hotter in the cabin than it is, then the vents will not change over fully to full heat.

A pure guess of course.

Pollen filter should have been changed on service.

Ill let you know how it goes.

Cheers

Yes it sucks and i will be returning probably tomorrow after work, going to try and keep it civil to start, unless i get no satisfaction.

Water leak fixed ? well i hope so.

I suspect the problem may be the Temp Sensor in the cabin myself, but its not for me to diagnose the problems and pay them at the same time, be surprised if its the Matrix as water, hot water appears to be flowing in and out of the pipes through the bulkhead, way too hot to touch, but if the temp sensor is thinking its hotter in the cabin than it is, then the vents will not change over fully to full heat.

A pure guess of course.

Pollen filter should have been changed on service.

Ill let you know how it goes.

Cheers

How's your coolant?

Yes it sucks and i will be returning probably tomorrow after work, going to try and keep it civil to start, unless i get no satisfaction.

Water leak fixed ? well i hope so.

I suspect the problem may be the Temp Sensor in the cabin myself, but its not for me to diagnose the problems and pay them at the same time, be surprised if its the Matrix as water, hot water appears to be flowing in and out of the pipes through the bulkhead, way too hot to touch, but if the temp sensor is thinking its hotter in the cabin than it is, then the vents will not change over fully to full heat.

A pure guess of course.

Pollen filter should have been changed on service.

Ill let you know how it goes.

Cheers

Think you will find that the temp sensor will only come into play when the heater unit is in Auto mode - manually setting the temp to max and you should

get max temp.

Hope you get it sorted without any additional cost though.

Mick

i stand to be corrected if it dont work on the corolla, but..... iv cured this problem in the past on a mk3 cavalier by running the engine from cold with the water expansion cap off , heater set on cold at full power, as the engine warmed up i alternated the heater setting from hot to cold rapidily... air bubbled up thro the expansion tank , the water level dropped. turned off engine, topped up water to max and all was fixed... there was an air lock in the heater matrix. gotta be worth a try????

Ok so phoned them today and car is booked back in next Thurs, could have got it in earlier but i requested a courtesy car so this was the earliest they could do.

Explained situation and said i assume this is FOC, of course Sir was the reply, so lets see what happens.

Coolant, well that was the first thing i checked which was low, few weeks back, so topped up and it dropped again, this was the other reason i put car in and is why they changed the pump, ill see if this is cured by the time it goes back in next Thurs.

Mick you could well be correct ......

Bert, yes has to be worth a try and i may give it a go, got nothing to loose.

I know its not right, drove to work this morning with temp set to 29 - 30 all the way, 1/2 hour drive and i kept my coat on, i never used to have to have it above 24 with coat off after 5 mins max.

Well ill keep you updated anyhow and thanks for the opinions/advice, appreciated as always.

As in Post #6 - try and reverse flush the matrix first to see if any crud comes out.

Heater matrix can be removed from the passenger side - take the glovebox out and you will see the metal pipes coming through from

the bulkhead and going onto the heater unit.

Mick

Cheers Mick. I already noticed the metal inlet/outlet pipes for the core when i did my filter change. Furthermore i have done few more checks & this is what i've found so far.

The Inlet/outlet metal pipes behind glove box are equally warm (doesnt suggest blockage but i could be wrong???). Further more air is equally warm coming out of the vents.

The function of damper Diverter from Cool to hot works perectly & cable is intact (doesnt suggest signal loss to the diverter)

I am discounting thermostat on the engine block as the heater pipes get warm to the extent one would find it hard to hold for long due to temperature.

Another thing i noticed i had the car idling/revving at around 1000-2000rpm for 20 mins & would expect the heater to come on & temp gauge to rise but none of that happened. The temp gauge stays half way & i have to admit the heating was slightly warmer but The coolant flow pipes didnt even pressurise. I could take of the radiator cap & touch the water & it was warmish. thats in contrast to the hot core pipes. I am unable to explain how this could be possible?

Before you ask the car doesnt suffer from coolant loss. The pink coolant looks ok with no rust/gunk.

I am now looking at 2 possibilities.

A !Removed! tight air lock in the heater core matrix. Does any one know if there is a bleed valve for the matrix where i could bleed out any air if it exists?

Or i have got the wrong mix of coolant that doesnt heat up as well & change of coolant may cure the issue. btw i have had this coolant in the car since i bought it 2 yrs ago & never had to top it up. regardless of the existing coolant age i am going to change it with the same stuff (long life) which i already bought & its ready to go in but before i do that i want to eliminate all possibilities. I am still thinking of either taking the dash out to take a closer look at the core or to do a reverse flush just to satisfy my curiosity. which pipe is the inlet at the firewall? the one on the left (as you face the car standing in front of it) or the one on the right? :P cheers

Ok so phoned them today and car is booked back in next Thurs, could have got it in earlier but i requested a courtesy car so this was the earliest they could do.

Explained situation and said i assume this is FOC, of course Sir was the reply, so lets see what happens.

Coolant, well that was the first thing i checked which was low, few weeks back, so topped up and it dropped again, this was the other reason i put car in and is why they changed the pump, ill see if this is cured by the time it goes back in next Thurs.

Mick you could well be correct ......

Bert, yes has to be worth a try and i may give it a go, got nothing to loose.

I know its not right, drove to work this morning with temp set to 29 - 30 all the way, 1/2 hour drive and i kept my coat on, i never used to have to have it above 24 with coat off after 5 mins max.

Well ill keep you updated anyhow and thanks for the opinions/advice, appreciated as always.

Mate ive read all your posts. Looks like a massive rip-off by Mr T. Bet the leak was nothing more than a drip from the thermostat gasket that sits exactly behind the alternator or a cut in the pipe that shouldnt have cost more than a tenner in parts. I would ask them for money back as they've demonstrated that changing 80% of the coolant system hasnt fixed ur issue. I do hope though when they return the car to you that the heater is working for you.

As in Post #6 - try and reverse flush the matrix first to see if any crud comes out.

Heater matrix can be removed from the passenger side - take the glovebox out and you will see the metal pipes coming through from

the bulkhead and going onto the heater unit.

Mick

Cheers Mick. I already noticed the metal inlet/outlet pipes for the core when i did my filter change. Furthermore i have done few more checks & this is what i've found so far.

The Inlet/outlet metal pipes behind glove box are equally warm (doesnt suggest blockage but i could be wrong???). Further more air is equally warm coming out of the vents.

The function of damper Diverter from Cool to hot works perectly & cable is intact (doesnt suggest signal loss to the diverter)

I am discounting thermostat on the engine block as the heater pipes get warm to the extent one would find it hard to hold for long due to temperature.

Another thing i noticed i had the car idling/revving at around 1000-2000rpm for 20 mins & would expect the heater to come on & temp gauge to rise but none of that happened. The temp gauge stays half way & i have to admit the heating was slightly warmer but The coolant flow pipes didnt even pressurise. I could take of the radiator cap & touch the water & it was warmish. thats in contrast to the hot core pipes. I am unable to explain how this could be possible?

Before you ask the car doesnt suffer from coolant loss. The pink coolant looks ok with no rust/gunk.

I am now looking at 2 possibilities.

A !Removed! tight air lock in the heater core matrix. Does any one know if there is a bleed valve for the matrix where i could bleed out any air if it exists?

Or i have got the wrong mix of coolant that doesnt heat up as well & change of coolant may cure the issue. btw i have had this coolant in the car since i bought it 2 yrs ago & never had to top it up. regardless of the existing coolant age i am going to change it with the same stuff (long life) which i already bought & its ready to go in but before i do that i want to eliminate all possibilities. I am still thinking of either taking the dash out to take a closer look at the core or to do a reverse flush just to satisfy my curiosity. which pipe is the inlet at the firewall? the one on the left (as you face the car standing in front of it) or the one on the right? :P cheers

If the pipes are equally warm/hot, that would almost rule out an airlock in the Matrix itself tbh.

Ergo, if the pipes are warm/hot, it still wont rule out an internal restriction/partial blockage in the Matrix eg Manufacturing problems ( solder ingress into the core tubes ) causing a restriction.

Picture below is what your looking for in regards to flow direction - when you reverse flush the Matrix, catch what you flush into a bucket so you can see the results.

Mick

Hello Mate

Further Note: Problem seems to have been fixed. An Open thermostat that was warming up the water but not warm enough.

A NOTE TO ALL TSPORT OWNERS. If you get a similar issue & dont want to spend time like me looking for a solution 1stly have a good look down the expansion/filler tank of the coolant & look for loose debris. If you find stuff resting at the bottom pretty certain it warrants a backflush of the heater matrix (2 hoses joining to aluminium pipes going into the firewall & disappearing into the car. If you dont see any debris then let the car warm up & idle for about 20-25 mins. if the fan doesnt kick in focus on the big rubber hose connected to the top of radiator. this should be really hot, so hot that you cant touch it for more than a second. Be very careful!!! this could give you burns. if it is less hot you will be able to hold the hose momentarily (up to 5 seconds or more). if you are able to hold it you are pretty much on the path to replacing a thermostat which is on the inlet side (follow the bottom radiator pipe disappearing behind alterantor. Yep, you are right. Alternator needs to be removed & so does the belt. Order a new part from Mr T 90916-03084 & order gasket/Oring also 16325-62010. Not A difficult job but a pain in the butt. Need good sets of tool. Darin the radiator but Dont flush the engine block if you dont find any debris elsewhere. Be sure to remove live terminal from the Battery because that runs directly to the alternator & while doing the job you are likely to wet your hands & will be working close to a live dc cable that can generate a fair amount of current, enough to give one a belt, make them jump & hit their head on the underside of the bonnet.

Cheers

Thanks for the info :)

I think my issue is more along the lines of LAA69s as my hoses are all pretty hot and the fan is kicking in. I'm not overally concerned as its warm enough to de-ice windows, just takes a little longer.

LAA, did you manage to get your car back into Toyota for the second time the other day? Really keen to know what they did to fix it as they had already done your thermostat, unless its still in the garage at the moment! :)

Rolla went in yesterday morning and is still there.

Spoke to them today and they said the Matrix is fine as is getting hot as it should, they believe the problem lies with the vents that adjust when the temp is changed up/down, you can hear them if you listen.

Possibly a stepper motor, had to remove the dashboard, hopefully i'll know more Monday and will update here if i do.

So total spent so far is still £420, the current diagnosis is FOC but once the problem is found, there will be a cost attached i think for repairs, we will see .........