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bebito

Weak Heater In Corolla T-Sport!

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Hi All,

I recently bought a 2003 Corolla T-Sport and it's a fine car - the ONLY problem with it is that the cabin heater only gives a hint of heat, even when the engine is hot after 20+ minutes of driving.

I have had a new thermostat put in, checked all the vents and flaps and they are working as they should. The fan is blowing fine, just hardly any heat. I have taken the coolant cap off and run the engine for a while to try and get rid of any airlock there might be in the coolant. It has the digital climate controls and I whack it up to "Hot", but "Hot" it, well, isn't.

I finally took it to my Toyota dealership (in the Summer, I should add), and they put a temperature probe in the air vent with the heater on full blast and told me it was 30 something degrees, and I "can't expect more than that", and charged me 40 quid.

There's a hot 2ZZ-GE engine right in front of me producing lots of heat. So, why is it so hard to get some of that heat into the cabin?

It was -1C last night and I pondered this as I sat in my T-Sport and considered investing in a parka.

Any ideas?

Thanks in advance.

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Hi - it's probably your matrix. Fairly common issue, but can be a few different causes - set aside some time and have a read through this thread. Quite a few have been down to the the matrix needing cleaning or replacing, but there are several other points to check, sounds like you've been through most of them though.

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Oh no not again, Matrix Matrix Matrix, great film, crap in a Corolla......

Good luck....

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Hi - it's probably your matrix. Fairly common issue, but can be a few different causes - set aside some time and have a read through this thread. Quite a few have been down to the the matrix needing cleaning or replacing, but there are several other points to check, sounds like you've been through most of them though.

Thanks Morgie and LAA69, I'll have to take it in to a garage for a matrix flush as I live in a flat which means no garden hose. I'll post if it's successful, otherwise I'll just sulk.

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Good luck with that Bebito. Note, for me just flushing it with the hose wasn't enough, not until I actuallly put through some cleaning agent (details here). However the garage will be more used to flushing them and possibly use a high pressure hose compared to the garden one I used. Definitely worth trying anyway, hope it results in some heat!

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Hi all, thanks for all your suggestions. I found something out today that might be of interest to anyone who is suffering from a weak heater in their Corolla.

On my CTS, the inlet and outlet pipes of the heater matrix both get very hot, so flow is fine. In fact, the flow might be TOO GOOD. Read on to see how this might be the problem.

I took it to my local mechanic today. He had a good think and reckons it's an engineering error in the heating system: the water goes around the heater matrix too quickly, so it doesn't have time to exchange the heat to the air flowing over it.

He demonstrated this by partially clamping the heater matrix inlet hose, thus slowing down the flow of water into the matrix. This immediately improved the heat coming through the vents into the cabin!

It's not really hot but it is a definite improvement. I'm going to try it out for a few days, then go back to him and he might clamp the outlet hose as well to see what that does (I'm talking about where the two hoses pass through the bulkhead behind the engine). I don't know why he didn't try that today, but he was busy and probably couldn't be bothered.

Has anyone else tried this? Let me know and I'll post my progress with this method.

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Interesting. What did he clamp it with?

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im in the same boat ,so im listening also

Have you tried cleaning and flushing the matrix yet? That sorted it for me. A few others have had success with it, someone else messaged me this week saying it had also got them some heat. Need to be careful when cleaning though as I think a few have had matrix that are maybe damaged and end up leaking. Method I used is in the post linked above in previous reply.

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Hi All,

I recently bought a 2003 Corolla T-Sport and it's a fine car - the ONLY problem with it is that the cabin heater only gives a hint of heat, even when the engine is hot after 20+ minutes of driving.

I have had a new thermostat put in, checked all the vents and flaps and they are working as they should. The fan is blowing fine, just hardly any heat. I have taken the coolant cap off and run the engine for a while to try and get rid of any airlock there might be in the coolant. It has the digital climate controls and I whack it up to "Hot", but "Hot" it, well, isn't.

I finally took it to my Toyota dealership (in the Summer, I should add), and they put a temperature probe in the air vent with the heater on full blast and told me it was 30 something degrees, and I "can't expect more than that", and charged me 40 quid.

There's a hot 2ZZ-GE engine right in front of me producing lots of heat. So, why is it so hard to get some of that heat into the cabin?

It was -1C last night and I pondered this as I sat in my T-Sport and considered investing in a parka.

Any ideas?

Thanks in advance.

hi

may be well off the mark here but here goes.on some cars the temp control operates a valve that controls the water flow through the matrex,other cars have air flow control, mixing hot with cold air to get the desired temp in car.

i had a cortina some years ago that had a good heater in it,till one winter when i went to use it i found the the heat no better than tepid.

after checking this and that i could not fault anything,untiil i remembered in the summer before that i had a cracked windscren,well more than crack,landed up with a big hole in it.

when the chap replaced it he cleaned up a fair bit of glass from the cabin,but some must have got down the screen vent and stopped one of the flaps closing.

anyway after stripping out the heater box of bits of glass the problem was solved.have you had a broken screen.

i dont know the corolla system but this could be your problem, if you tried everything else.

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im in the same boat ,so im listening also

Have you tried cleaning and flushing the matrix yet? That sorted it for me. A few others have had success with it, someone else messaged me this week saying it had also got them some heat. Need to be careful when cleaning though as I think a few have had matrix that are maybe damaged and end up leaking. Method I used is in the post linked above in previous reply.

funnily enough i read your thread when you put it up ,brought the mr muscle n everyfin ,then the bottle leaked in my boot and i never bothered getting round to it again lol

i aint exactly freezing in there but it sure aint 30degrees , i need to get to a garage as i liv in a apartment and dont have a hose

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Interesting. What did he clamp it with?

He used this type of clamp, which he calls a restrictor. Here are two angles that show it in place.

I haven't had a broken windscreen, but I am the 5th owner so obviously it's possible glass or other stuff could be blocking a flap and letting in cold air along with hot. Just haven't got round to dismantling the whole heating system yet to investigate!

Thanks for the comments everyone. Tomorrow's acid test will be to see if I get heat after a few minutes idling rather than having to get the block really hot, like 20 minutes of revving then some heat. I'll keep you posted, and if this clamp idea works, it will be a nice cheap solution. I have my doubts, but I'm not handy enough to get into heater matrix flushing and all that so I'm going with what my mechanic says.

post-100367-073623000 1290792064_thumb.j

post-100367-074423600 1290792080_thumb.j

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Don't like the look of that :unsure:

What about to much preassure build up in the system if you restrict it to much?

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have the same problem its driving me mad! how do you go about cleaning out the matrix? what do you disconnect?

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Don't like the look of that :unsure:

What about to much preassure build up in the system if you restrict it to much?

build up what pressure,you can block of both pipes completly and not effect anything pressure wise.

with the valve type control these shut off the flow to the heater.does that cause pressure build up.

cant see your point.

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have the same problem its driving me mad! how do you go about cleaning out the matrix? what do you disconnect?

You might want to have a look at the method I used, it's in this post, part of this thread I linked in my first reply on this one. Worth a read through from start to the end - bit of a long one though!

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Don't like the look of that :unsure:

What about to much preassure build up in the system if you restrict it to much?

build up what pressure,you can block of both pipes completly and not effect anything pressure wise.

with the valve type control these shut off the flow to the heater.does that cause pressure build up.

cant see your point.

My point was I was unsure myself if this would happen this is why I asked the question :ffs:

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Well guess what everybody, this hose-clamping lark makes barely any difference. Back to the drawing board! Our quest for Rolla heat continues...

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New heater matrix. Job done. Or flush it by removing it. It isnt hard to do.

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New heater matrix. Job done. Or flush it by removing it. It isnt hard to do.

maybe i am mistaken but isn't the matrix a total b*tch to get to? i was either told or read somewhere it involves removal of nearly the whole dashboard?

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Yes it is. Have you checked the post I linked above? I'd really recommend you flushing it and using something to clean it in place as mentioned.

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have the same problem its driving me mad! how do you go about cleaning out the matrix? what do you disconnect?

You might want to have a look at the method I used, it's in this post, part of this thread I linked in my first reply on this one. Worth a read through from start to the end - bit of a long one though!

that link is spot on mate :thumbsup:

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anyone else find with this heater problem that its ok when crawling along in traffic or stopped at lights but when you get on fast roads its much worse?

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