trouble with cabin heating

[loofon]

I have a Lexus 400 hybrid 57 plate. Recently the in-car heating system has started to have problems.  It becomes warm at about 2-5 minutes into a journey but then after about 5 minutes it goes completely cold.  I've tried turning it off completely for a few minutes and trying again but that doesn't work.  We have checked the coolant which is fine.  About six months ago the dashboard started to get really warm but that has now stopped.  Not sure if t is connected.  Just wondered if anyone had any ideas what the problem could be?

[ChrisKaye]

Hi, sounds like you could have a pocket of trapped air in the heater core.

Have you had any work done recently such as a new timing/cam belt?

[TigerFish]

Could be the servo motor that controls the temperature. Maybe playing up and giving up the ghost when it gets warm.

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[ChrisKaye]

I've heard that when the servo plays up it is sometimes accompanied by a light clicking noise as it has trouble changing the airflow direction 'flap' (for want of better words!

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[TigerFish]

Yeah, this so true depending on which one is buggered. The airflow direction servo is a different one to the temperature one (albeit a flap is probably involved somewhere as well). On my GS430, the air flow direction servo went (changed it last week) and that did make a clicking noise sometimes, but not every time.

If you are needing to change one, be sure to search fleabay by part number once you've found the right one. Second hand servos were expensive for the GS430, but they are the same part number as the IS200 one, which were much cheaper ;) I'm sure later models would share these types of components as well.

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[loofon]

thanks for all your answers ,Only just seen them on my emails ,cheers again and I will let you all know when i get it sorted :)

 

[PCM]

On 2/4/2016 at 10:49 AM, ChrisKaye said:

I've heard that when the servo plays up it is sometimes accompanied by a light clicking noise as it has trouble changing the airflow direction 'flap' (for want of better words!

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I had the ticking noise on my RX. Servo motor replaced, ticking disappeared.

( Never affected the heating though ... )

[Madartsoft]

Hi PCM,

Did you replace it yourself or Lexus? How much it costs?

[PCM]

Lexus did it under warranty, so I don't know how much it would have cost.

The sound drove me mad so I would have paid £ to get it done...!

[Madartsoft]

I also have similar problem. the warm/cold temp is ok but it seems that it struggling to find the correct position and some strange noises are generated. The sound changes when switch manually the air direction. So I guess it's a mode servo. The Lexus quoted £231 inc. VAT. for part.

[Bigandybelfast]

I'm suffering the same issue. Clicking noises and cold air. Causing the engine cooler fan to engage more regularly and negatively affecting petrol consumption. HELP!