No heating

Lucazade · September 14, 2020

I barely get any heat from the airconditioning.

I have changed the coolant (it was clean)

Checked the heather matrix, both from the firewall and in the footwell - it gets hot

Checked the flaps’ motors (they all work)

Checked the air mix flap itself (it moves)

Checked the air temperature sensor under the steering wheel (it works)

Yet when I put the heating on, even at max temp I only get some mildly warm air, whether the aircon is on or off.

Has anybody got the AC unit apart to show me how it works or has any idea what else I could look at?

Thanks

IS300KK · October 21, 2020

I have this problem with my IS300, have been told repeatedly by garages that there is nothing wrong with the heater. The air con works very well, but very little in the way of heating. Have just started fixing the car up, so if I get any answers will pass them on.

Andrew250 · October 21, 2020

I recently purchased my IS250 and I am having the same issue. The air is only coming out luke warm at maximum setting so interested in any ideas for a fix.

Lucazade · October 22, 2020

I have now sold my car, but lately described the issue to a mechanic who thought it would be a case of blocked heater matrix. Garages might think it's fine because both inlet and outlet pipes are hot, but what in reality is happening is that some units can have the water going directly from one pipe to the other (this is not a IS200/300 heather matrix, BTW):

The solution is to flush it with a cleaner, but that may or may not work depending on the blockage. If it doesn't I'm afraid it's a dashboard out job to replace it

steve2006 · October 22, 2020

Have you checked the pollen filter, chances are it’s never been replaced and is totally clogged severely restricting air flow.

Lucazade · October 22, 2020

Changed annually - at least in my case, don't know the other people in the thread

Lucazade · October 22, 2020

Just to clarify from my end - the issue was temperature, not airflow

IS300KK · October 22, 2020

Thanks for the replies.

Just like Lucazade, my issue is temperature, not airflow.

The blocked heater matrix sounds like a possibility, because they've been convinced that it was heating, whereas I was freezing when driving the car. I haven't had the pollen filter done for a while, that's a really useful suggestion. (We had a mouse nest in the pollen filter of another car on the drive).

The heater not working is a big reason I haven't been driving it.

Will mention it when I pick the car up.

All the best

Amanda

Lucazade · October 23, 2020

13 hours ago, IS300KK said:

The blocked heater matrix sounds like a possibility, because they've been convinced that it was heating, whereas I was freezing when driving the car. I haven't had the pollen filter done for a while, that's a really useful suggestion. (We had a mouse nest in the pollen filter of another car on the drive).

If the pollen filter was clogged, airflow would be reduced for cold air too.

IS300KK · October 23, 2020

11 hours ago, Lucazade said:

If the pollen filter was clogged, airflow would be reduced for cold air too.

I was hoping for the cheaper fix! I phoned the garage today asking them to check both, so we'll see. It would be nice to have an answer.

BTW, it passed the MOT with just a headlamp lens clean-up.

IS300KK · November 4, 2020

Well, the garage replaced the pollen filter and said the heating was now working. Unfortunately, it has made no difference.

Today, I left it with an Independent Toyota / Lexus specialist, who has very good reviews online, so fingers crossed.

Lucazade · November 4, 2020

Good luck. I'm be interested to know what it turns up to be

IS300KK · November 4, 2020

I had thought that I was just being a bit fussy about the heater, and could just stick to using the car only in summer, but today realised that the windscreen doesn't clear without a bit of heat, so pretty essential really! Will pass on anything they find, they have experience of dealing with these cars and seem motivated. I'm looking forward to possibly finding out, at last, what the problem is, and giving my car a new lease of life.

IS300KK · November 9, 2020

The heater is fixed!!!!!

The heater matrix had a blockage, which the good folks at Osaka Independent Lexus specialists in Newport spent quite a while clearing, I'm so pleased! It's now going to have a service and timing belt change, all at very reasonable cost, using Lexus original parts.

Apparently Lexus no longer manufacture the heater matrix, but it is available as a non-original copy.

Thanks to the suggestions on this forum, I had a starting point to work from.

Lucazade · November 10, 2020

Glad it worked out without removing the dashboard. Replacing the heather matrix could have been expensive, even using a non-OEM part, because of labour.

These issues highlight the importance of changing coolant regularly, which I hope they did when they flushed the matrix.

Farqui · November 10, 2020

Great news Amanda / @IS300KK :clapping:

I'm really pleased it was fixed for you without too much fuss, mine was far too blocked and after repeated flushing/back flushing over several years I recently bit the bullet and had the heater matrix replaced. So it's just bread/water for me now 🤣

IS300KK · November 10, 2020

8 hours ago, Farqui said:

Great news Amanda / @IS300KK

I'm really pleased it was fixed for you without too much fuss, mine was far too blocked and after repeated flushing/back flushing over several years I recently bit the bullet and had the heater matrix replaced. So it's just bread/water for me now 🤣

Thank you! They did say it's possible it will clog again, but fingers crossed. I'm just really pleased they took me seriously after other places were adamant it was working.

IS300KK · November 18, 2020

Picked it up today, after a service and various bits and pieces. It felt great to drive, and the heater was working properly at last!

Very impressed with Osaka Toyota / Lexus specialists in Newport, I will definitely be going back there for any further work, and would wholeheartedly recommend them.