2008 GS300 No heat on passenger side

[KevH]

Well as the temperature has started to drop, she who must be obeyed has noticed that there is no heat coming out of the passenger side of the car. Ive owned the car for 5 years and it has a full Lexus service and warranty since new, so since it was going in for a service I asked lexus to look at it and they said that it was a faulty heater matrix and it was going to be over £1100 to fix it (dashboard has to come out). They think that half of it is blocked ! happens to be the opposite end from the inlet and outlet pipes.

I decided to bring it home and have a look myself but Im getting nowhere fast !

Here is what I have observed so far :

• Cooling fluid is clean, bright pink and no signs of corrosion or debris anywhere.
• All motors on both sides of the heater box move when commanded.
• Inlet and outlet pipe of the heater matrix are burning hot.

 

This is what I have tried so :

• flushed back words with a hose (collected water into a bucket - no signs of anything coming out)
• put two bottles of radiator flush in and reversed the inlet and outlet hoses to flush it backward and went for a long drive
• blow compressed air through it in reverse - clean fluid came out

 

Any ideas ?? Could it be the water pump (not enough pressure)?? I had a new water pump fitted several years ago (there was no heating at all).

If I do need to replace the heater matrix how hard is it to get the dashboard out ??

 

Thanks

Kev

 

 

[Zotto]

In that GS I remember they recommend to close air recycle before changing air conditioner filter, else it could happen to break a leverage (or something similar) that makes air flow: try giving a look there after correctly removing air filter passing by glovebox.

[Farqui]

My GS has cooler output on the passenger side (not cold) which I initially thought were bad blend doors/servo's but they all checked out.  Servo work is a pig of job by the way, so I hope that is not your issue.

I've also read about the matrix getting clogged so intend to get give the heater matrix a flush and soak to see if that helps.

You're ahead of me already and it's disappointing that you haven't dislodged anything yet. Are you considering soaking the matrix guts with an appropriate solution?

As a footnote, I mentioned the issue to a former Lexus tech and he said that low passenger temps could be due to low AC...I haven't followed up on this and in 2 years my AC works fine so hasn't been regassed.

[KevH]

Zooto - I already checked the cabin filter and its working perfectly

 

Farqui - I put double the amount of fluid into the cooling system than was recommended and rather than leaving it the recommended 10 minutes its been in for 4 days so far and its dislodged nothing that I can see 😞. If it was corrosion I would expect to see some discoloration of the anti freeze but there is nothing. I did think about draining the matrix and putting pure cleaner in but I dont think its going to make a difference.

Lexus refused the warranty claim saying that "corrosion" isn't covered by the warranty !

My AC compressor was replaced a year ago by lexus and the AC works great.

Thanks

Kev

 

[Farqui]

Ah sorry, re-reading your OP I now see that you have already tried a flush solution 

What is your hose pressure like? 

On sample vids I've been them use a valve to pulse the flush fluid through, sometimes this can help dislodge any blockages.

Have you done any investigation on the heater matrix servos?  Are there any odd noises in the dash during start/stop or when operating the heater controls?

I hope you don't have to replace the matrix but if you do then I believe there are only a few bolts holding the dash in.  However there are many other components to remove in order to get the dash out  

[KevH]

11 minutes ago, Farqui said:

Ah sorry, re-reading your OP I now see that you have already tried a flush solution 

What is your hose pressure like? 

On sample vids I've been them use a valve to pulse the flush fluid through, sometimes this can help dislodge any blockages.

Have you done any investigation on the heater matrix servos?  Are there any odd noises in the dash during start/stop or when operating the heater controls?

I hope you don't have to replace the matrix but if you do then I believe there are only a few bolts holding the dash in.  However there are many other components to remove in order to get the dash out  

I have pretty good water pressure at my house so the hose pressure is way more than the water pump would produce and I let it running a good 5 minutes in both directions (backwards first).

I also tried blowing out the fluid with 40psi compressed air.

Both servos on the passenger side move when I change the temperature and if I set the blowers to feet mode then you can see inside the heater box and I can see the air flap inside moving when I set the temperature. No odd sounds and everything moves smoothly

Im really hoping not to have to take the dash out as it looks like a nightmare (hence the price from Lexus) - does anyone have any guides or videos ???

Ive got an endoscope that im going to try and get inside the airbox or maybe remove the blower as that would let me check inside the heater box but that looks like a nightmare job as well 

 

Kev

 

 

[royoftherovers]

45 minutes ago, KevH said:

Zooto - I already checked the cabin filter and its working perfectly

 

Farqui - I put double the amount of fluid into the cooling system than was recommended and rather than leaving it the recommended 10 minutes its been in for 4 days so far and its dislodged nothing that I can see 😞. If it was corrosion I would expect to see some discoloration of the anti freeze but there is nothing. I did think about draining the matrix and putting pure cleaner in but I dont think its going to make a difference.

Lexus refused the warranty claim saying that "corrosion" isn't covered by the warranty !

My AC compressor was replaced a year ago by lexus and the AC works great.

Thanks

Kev

 

Sorry to hear your news Kevin.

How have Lexus been able to determine that corrosion is the problem?

Who owns the local Lexus franchise?

[KevH]

50 minutes ago, royoftherovers said:

Sorry to hear your news Kevin.

How have Lexus been able to determine that corrosion is the problem?

Who owns the local Lexus franchise?

Now that is the million dollar question ! I quizzed them about that and according to the service manager the mechanic was able to feel both ends of the heater matrix, the driver side was hot and the passenger side was cold therefore is must be corrosion and the warranty was rejected. 

Now that ive had a look myself I would love to know how the mechanic achieved that considering the heater matrix slides into the air box and you can only touch the driver end of it !

The dealer is Lexus Edinburgh so its Eastern Western Group

Kev

 

[royoftherovers]

15 minutes ago, KevH said:

Now that is the million dollar question ! I quizzed them about that and according to the service manager the mechanic was able to feel both ends of the heater matrix, the driver side was hot and the passenger side was cold therefore is must be corrosion and the warranty was rejected. 

Now that ive had a look myself I would love to know how the mechanic achieved that considering the heater matrix slides into the air box and you can only touch the driver end of it !

The dealer is Lexus Edinburgh so its Eastern Western Group

Kev

 

I would take up the matter in writing with the Dealer Principal of Lexus Edinburgh.

A mechanic`s guess is not sufficient to determine a cause and it is not Lexus Edinburgh`s job to turn down a warranty claim it is TGW`s, the policy administrator. They are supposed to process the claim on your behalf.

If necessary seek the view of a local qualified heating / air con engineer, before you return the matter to Lexus Edinburgh.

Good luck

[Farqui]

Kevin, can you pop up a picture of the hoses you use to flush? 

I did some research a while back and the heater matrix hoses were at the back of the engine bay on the passenger drivers side and not near my airbox.

[KevH]

1 minute ago, Farqui said:

Kevin, can you pop up a picture of the hoses you use to flush? 

I did some research a while back and the heater matrix hoses were at the back of the engine bay on the passenger side and not near my airbox.

Sure its dark now but will get them for you in the morning. They are on the drivers side right on the bulk head. You will also have two on the passenger side for the cold radiator.

Kev

[JeffL]

Hi Kevin, what mileage has your car done? 

[KevH]

14 minutes ago, JeffL said:

Hi Kevin, what mileage has your car done? 

approaching 100K

[Farqui]

Like this pic ? - hijacked from the www, sorry I can't recall where

[KevH]

55 minutes ago, Farqui said:

Like this pic ? - hijacked from the www, sorry I can't recall where

Yes thats exactly where they are but I will get some better pictures for you tomorrow. I found that a standard garden hose slides inside the existing rubber hoses and seal ok if you press them in far enough 😉

 Kev

[Odysseus]

Just some random thoughts based on what I’ve read this far...

Does the drivers side get hot? As in can you turn the heat all the way up to max and feel hot air? If so I can’t see how it can be the heater matrix. Surely there aren’t separate heater matrices in the car?!

If not is the thermostat definitely ok?

Assuming you can get heat on one side then my thinking is it must be a blend door issue, rather than a heater matrix one.

As an aside my wife complained of cold air on her (passenger) side in my 2008 GS. I whacked the heat up to full which seemed to help at the time and after the journey played around with one side high one side low, then vice versa. This seemed to “unstick” the issue and I try to do it again every month or two. My sense told me it was blend doors getting lazy spending their lives barely needing to move much which asking them to perform at the limits of their range seemed to help with.

After reading this thread I’m doing to do this exercise again next time I drive the car.


Sent from my Iphone using Tapatalk

[KevH]

Yes the drivers side works perfectly, nice and hot which is why I’m having difficulty believing it’s the matrix as well.

i have removed the glove box which allows me to get to the servos, I’ve removed the foot well duct and this allowed me to see inside the air box, when I change the passenger temp I can see the blender door moving inside the air box.

 

i will give the one side high one side low trick in the morning.

 

thanks

Kev

[Odysseus]

Best of luck Kev, let us know how you get on.

[Farqui]

Andrew @Odysseus, the heater core has both the feed and return pipes on the same side of the matrix, so flow on the far side is reduced and can clog.  

Here's a pic crib'd from the www that shows what can occur (note: it's from a US forum)

[KevH]

18 hours ago, Farqui said:

Kevin, can you pop up a picture of the hoses you use to flush? 

I did some research a while back and the heater matrix hoses were at the back of the engine bay on the passenger drivers side and not near my airbox.

Here are the photos. If you remove pipe A temporarily to get access there are two hose clips (circled) on pipe B and C , move these down the pipe and with some force the pipes unplug. Ive marked the water flow (B is the inlet to the matrix) so stuff a hose pipe up pipe C to flush it.

Kev

[KevH]

4 minutes ago, Farqui said:

Andrew @Odysseus, the heater core has both the feed and return pipes on the same side of the matrix, so flow on the far side is reduced and can clog.  

Here's a pic crib'd from the www that shows what can occur (note: it's from a US forum)

Yeah, I can see how that could happen 😞

[KevH]

5 minutes ago, Farqui said:

Andrew @Odysseus, the heater core has both the feed and return pipes on the same side of the matrix, so flow on the far side is reduced and can clog.  

Here's a pic crib'd from the www that shows what can occur (note: it's from a US forum)

Yeah, I can see how that could happen 😞 However if im not mistaken (I need to double check) the inlet is at the bottom of the radiator . (I could be wrong)

 

[Odysseus]

Thanks Lee for the really informative post and diagram.  Looks like a (rare) poor design from Lexus there.

Notwithstanding the inlet and outlet pipes being on the same side, I would have expected some nastiness or grotty water to have to come from the matrix with all the flushing that Kev is doing.

[Farqui]

Thanks Kevin @KevH, your photo's are great - they look the same on my vehicle.

The short hose runs to the clips are great as you then don't need to mess with the hoses on the firewall and risk causing a leak inside the cabin.

[Farqui]

9 minutes ago, Odysseus said:

Thanks Lee for the really informative post and diagram.  Looks like a (rare) poor design from Lexus there.

Notwithstanding the inlet and outlet pipes being on the same side, I would have expected some nastiness or grotty water to have to come from the matrix with all the flushing that Kev is doing.

You're welcome, they say "a picture paints a thousands words".

The design is not unique to Lexus and you'll find this design is common to many vehicles.

I guess it helps with packaging and keeping components compact.