Occasional creaking noise AC

Easterlily · April 21, 2020

Hello fellow Lexus owners.

I have owned my -15 Is300H for over half a year now and I am really satisfied and amazed over the complete packade that this car delivers. However I have noticed an issue that ive narrowed down to the AC of the car.

The sound is sort of rare and when heard only last for a couple of seconds. Sounds like the creak made when you sit down in an old leather sofa or like you let out a deep fart. Like 1 out of 4 times when i turn on the ignition (and the ac turns on) the sound is triggered. Occasionally this can also be heard when changing the AC temp between ca 19-21 C. Ill link a video showing the sound at its worst. Note that i normally can change the AC settings while the car is running without this noice - its occasional and rare and occurs more often as explained in the beginning - when i start the car first time in the day.

Now im not very car mech savvy so my guess could be completly wrong but i would think this could be some kind of servo or vent motor that is scratching against something or maybe needs lubricant?

Anyway. I hope someone can help me. I fear that even though the issue seems to be minor it could get worse im the future if i dont do anything about it. Ive tried to find answers and help but failed so far. Hopefully someone eöse have had this issue and has better knowledge 🙂

Video: https://youtu.be/J2wBfiLe2OI

chris1601 · April 22, 2020

That sounds like a flap in the ventilation matrix moving to adjust air between different vents. Probably just needs a little lube of some sort on what I imagine are rubber seals. I might be wrong though.

Shada · April 22, 2020

You sure it's not the brake booster? Press the brake pedal 5 or 6 times and see if the noise repeats.

Easterlily · April 22, 2020

9 hours ago, chris1601 said:

That sounds like a flap in the ventilation matrix moving to adjust air between different vents. Probably just needs a little lube of some sort on what I imagine are rubber seals. I might be wrong though.

Yeah sort of what i suspect. I have done a few car diy repairs before but as im far from an expert i would really like to get a bigger idea of what im supposed to do or look for. One of the major issues is that the sound both is rare and just lasts for a few secounds so even if i could open up some hatch iex by the cabindrawer i would have a hard time finding the problems.

Worth noting is the day i shot the video is the day this problem have been at its worst. Normally its just when i start the car and very rarely during ride.

I usually run auto mode on the AC. Maybe i should stop doing this and try a few different settings each week to see if i can zone out if a particular setting is a factor.

9 minutes ago, Shada said:

You sure it's not the brake booster? Press the brake pedal 5 or 6 times and see if the noise repeats.

Positive. As you can see in the video the noise appears deppendent on my AC inputs. The brake was not touched while filming.

Thank you both for your replies!

Easterlily · April 22, 2020

10 hours ago, chris1601 said:

That sounds like a flap in the ventilation matrix moving to adjust air between different vents. Probably just needs a little lube of some sort on what I imagine are rubber seals. I might be wrong though.

Do you have any experience or idea of how this doodad could be reached and checked/lubed?

Shada · April 22, 2020

OK I hadn't seen the video before I first posted but now I have it definitely looks as if the heat/cold flap is the culprit.

It's likely you will have to remove the side trims from the front of the centre console and look at the flaps behind the dash while someone else adjusts the temperature

200h · April 23, 2020

i have had the same issue on my last IS300h the ventillation unit was replaced under warranty luckily for me

here is my video of the noise apparently the dealer had never heard it before.

i believe it is a worn pivot point that created the noise

wharfhouse · April 23, 2020

My car (2014 IS 300h with 85,000 miles) makes that noise too - usually on start up first thing but I don't notice it at any other time - but I generally leave my climate control on auto and so don't make any large temperature changes once on the move. The car has always done this since I purchased it (at 2 years old with 40,000 miles on it) and so I just assumed it was one of the air con flaps going through a full opening when I first start the car so didn't give it any more thought. The noise hasn't got worse in the 3+ years and 45,000 miles I have had the car.

200h · April 23, 2020

i found it didnt make the noise if you left it on a low temperature

when you increased the temp it then made the noise

initially it didnt make the noise every day but after a few months

it happened everyday but only when you first started the car

in the morning and when leaving work 8hrs later

Easterlily · April 23, 2020

19 hours ago, Shada said:

OK I hadn't seen the video before I first posted but now I have it definitely looks as if the heat/cold flap is the culprit.

It's likely you will have to remove the side trims from the front of the centre console and look at the flaps behind the dash while someone else adjusts the temperature

Do you know if this is an easy process or do i have to unscrew a whole lot of stuff to get in?

Easterlily · April 23, 2020

9 hours ago, 200h said:

i have had the same issue on my last IS300h the ventillation unit was replaced under warranty luckily for me

here is my video of the noise apparently the dealer had never heard it before.

i believe it is a worn pivot point that created the noise

What is a pivot point? I googled it but only found a bunch of charts and locations. Nothing car related 😄

7 hours ago, wharfhouse said:

My car (2014 IS 300h with 85,000 miles) makes that noise too - usually on start up first thing but I don't notice it at any other time - but I generally leave my climate control on auto and so don't make any large temperature changes once on the move. The car has always done this since I purchased it (at 2 years old with 40,000 miles on it) and so I just assumed it was one of the air con flaps going through a full opening when I first start the car so didn't give it any more thought. The noise hasn't got worse in the 3+ years and 45,000 miles I have had the car.

Thats atleast a bit soothing. Was/is it always in the morning when you first start the car or have you had any other issues?

Shada · April 23, 2020

Not sure just how much you will have to remove I've not been in the dash of an is3 yet. I imagine it will be the forwarded side trims of the centre console and look up on your back twisted like a gymnast.

I know that noise would drive me nuts and I couldn't live with it.

wharfhouse · April 23, 2020

2 hours ago, Easterlily said:

Thats atleast a bit soothing. Was/is it always in the morning when you first start the car or have you had any other issues?

Only happens when I first start the car - and then not every time - never had any other issues though and the air con / climate control has always worked without an issue other than this noise sometimes when first starting up.

200h · April 23, 2020

1 hour ago, Shada said:

Not sure just how much you will have to remove I've not been in the dash of an is3 yet. I imagine it will be the forwarded side trims of the centre console and look up on your back twisted like a gymnast.

I know that noise would drive me nuts and I couldn't live with it.

i believe the whole dash had to be removed from the car

if you think about it the face air vents are at the top ot the ventillation unit

and the floor vents are at the height of the drive shaft tunnel

so overall its a big unit to take out , you also have to depressurise the aircon

system aswell .

Shada · April 23, 2020

2 hours ago, 200h said:

i believe the whole dash had to be removed from the car

if you think about it the face air vents are at the top ot the ventillation unit

and the floor vents are at the height of the drive shaft tunnel

so overall its a big unit to take out , you also have to depressurise the aircon

system aswell .

Yes I've removed many air units when replacing heater matrix. And it's nearly always dash out. (had a few avensis out but not lexus)

But to find the squeaking offender and possibly wd40 it may be visible with the side trims removed.

Most flap motors we replace (not lexus as they don't usually break) are done with the side trims out sometimes glove box too. (usually vw)

Shada · April 23, 2020

Just now, Shada said:

Yes I've removed many air units when replacing heater matrix. And it's nearly always dash out. (had a few avensis out but not lexus)

But to find the squeaking offender and possibly wd40 it may be visible with the side trims removed.

Most flap motors we replace (not lexus as they don't usually break) are done with the side trims out sometimes glove box too. (usually vw)

If it works but squeaks it's probably a dry moving part.

It's possible oiling may cure it. I'm curious Is just replace the whole thing under warranty a dealer approach to avoid investigation or comeback.?

Easterlily · April 24, 2020

10 hours ago, Shada said:

Yes I've removed many air units when replacing heater matrix. And it's nearly always dash out. (had a few avensis out but not lexus)

But to find the squeaking offender and possibly wd40 it may be visible with the side trims removed.

Most flap motors we replace (not lexus as they don't usually break) are done with the side trims out sometimes glove box too. (usually vw)

Okay. I guess its worth a shot. Ill try to find a manual on how to disasemble the side panels and glove box and see if the doodad is reachable. I havnt actually looked how the footwells surroundings look like, maybe this is an easy process that doesnt require a manual for a newbie.

12 hours ago, 200h said:

i believe the whole dash had to be removed from the car

if you think about it the face air vents are at the top ot the ventillation unit

and the floor vents are at the height of the drive shaft tunnel

so overall its a big unit to take out , you also have to depressurise the aircon

system aswell .

If this is the case its a no go. As wharf claims the issue wont neccessarily become worse the present state is absolutly livable. As i dont have warranty left i would bet this is an expencive repair.

Easterlily · April 24, 2020

Come to think of it. A whole different question. Ive found the handbrake to be rather strange in this car. So when I stop and just put the car in P and release the footbrake the car moves a few inches before making a stop and the shifter jumps as the wheels stop and i guess the cogs in the transmission causea the car to stay im place. Previously ive only driven manual cars and leaving the car in gear usually makes the car stay in place imidiately. Is the hybrid system causing this small gap and is it working as intended? I hope i explained good enough.

Now the same thing goes with the handbrake. If i stop the car put the transmission in P and press hard on the handbrake located next to the regular brake, the car still moves a few inches, although not as far as the scenario explained previously and the shifter doesnt wobble. Its like there is a gap between the actuall brake effect and the wheels moving. Once ive noticed when opening the door before releasing the footbrake the bottom of the car made a slap noice as the car made a small transfer before coming to a secure stop.

Is this also normal?

200h · April 24, 2020

the dealer told me if they had to buy one it would cost £1200 for the part alone

Thackeray · April 24, 2020

1 hour ago, Easterlily said:

So when I stop and just put the car in P and release the footbrake the car moves a few inches before making a stop and the shifter jumps as the wheels stop and i guess the cogs in the transmission causea the car to stay im place. Previously ive only driven manual cars and leaving the car in gear usually makes the car stay in place imidiately. Is the hybrid system causing this small gap and is it working as intended?

That sounds normal. Here's a video about the transmission and this section shows what's called the parking pawl, which locks the transmission when you engage Park.

So you can see that it's normal that there would be a bit of movement when Park is engaged. This is the same on all automatic cars, not just hybrid cars. (The video is actually about the P410 transmission which is for front-wheel drive cars. The equivalent is the L210 on the IS300h, which is a version used for rear-wheel drive cars but they work in much the same way.).

But when you use the foot-operated parking brake, there really shouldn't be much movement of the car - certainly not "a few inches". There might be a bit of movement but it should feel more secure than when you just engage Park on the transmission.

Easterlily · April 24, 2020

10 minutes ago, Thackeray said:

That sounds normal. Here's a video about the transmission and this section shows what's called the parking pawl, which locks the transmission when you engage Park.

So you can see that it's normal that there would be a bit of movement when Park is engaged. (The video is actually about the P410 transmission which is for front-wheel drive cars. The equivalent is the L210 on the IS300h, which is a version used for rear-wheel drive cars but they work in much the same way.).

But when you use the foot-operated parking brake, there really shouldn't be much movement of the car - certainly not "a few inches". There might be a bit of movement but it should feel more secure than when you just engage Park on the transmission.

Perhaps i have a habit of not pressing the handbrake hard enough. I actually dont use the imperial system where i live so saying a few inches might be faulty. Id say like it feels the car moves more or less a dm.

Thanks for the good info about the transmission. Feels good to know its supposed to work like that. To be sure, there is no damage done to it when the shifter makes this wobble then? I usually try to sneak when i release the brake slowly so that the movement speed is as minor as possible before the transmission locks it.

I recently did the large service and i guess the different brakes are tested in this, but i recieved no feedback of any faults - everything was in order according to the mechanic. Maybe they didnt try the handbrake however.

As you seem to have good knowledge about this type of transmission can i ask you, is it recommended to hold the brake when changing the gear from D to N to R and/or vise versa or can you do these manouvers without engaging the brake pedal at all? given that the car is not moving if changing between D and R ofcourse.

wharfhouse · April 24, 2020

4 hours ago, Easterlily said:

If this is the case its a no go. As wharf claims the issue wont neccessarily become worse the present state is absolutly livable. As i dont have warranty left i would bet this is an expencive repair.

I have extended warranty so could have probably had it looked at but I had seen the post some time back about the whole dash having to be removed to fix it and so decided I would live with it as it wasn't bothering me just to have it happen sometimes at startup and who knows what other problems removing and refitting the dash might cause.

Easterlily · April 24, 2020

3 hours ago, wharfhouse said:

I have extended warranty so could have probably had it looked at but I had seen the post some time back about the whole dash having to be removed to fix it and so decided I would live with it as it wasn't bothering me just to have it happen sometimes at startup and who knows what other problems removing and refitting the dash might cause.

True. I guess ill leave the issue as it is. Thanks for your insight.

200h · April 24, 2020

lexus chester made a mess of my car they scratched the paint on the A pillar when taking the dashboard

out, had mucky paw prints over the light grey interior panels, gave me a rattle by the dash airbag

and forgot to replace half the screws from the centre console and they wondered why i was ****** off with them,

PHIL the service manager needs to grow a pair as he wouldn't confront the guy who left the screws out

the guy should of been bollocked as he knew he hadn't replaced everything he had taken out.

wharfhouse · April 24, 2020

6 minutes ago, 200h said:

lexus chester made a mess of my car they scratched the paint on the A pillar when taking the dashboard

out, had mucky paw prints over the light grey interior panels, gave me a rattle by the dash airbag

and forgot to replace half the screws from the centre console and they wondered why i was ****** off with them,

PHIL the service manager needs to grow a pair as he wouldn't confront the guy who left the screws out

the guy should of been bollocked as he knew he hadn't replaced everything he had taken out.

That's why I decided to leave mine as is - that would all have annoyed me more than the occasional noise! My experience on other cars is that when mechanics start taking the insides apart it's never the same again...