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Heaters Taking a Long Time to “Get Hot”

Discussion in 'Leon Mk3 (2012-2020)' started by ben, Sep 17, 2019.

  1. ben

    ben Active Member

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    The heaters in my Leon Cupra 280 seem to take quite some time to get hot. It takes in excess of 10 mins for any heat to show and probably excess of 15 mins to get to full heat.

    In the meantime, if it starts getting warm and I whack up the flow and heat, it gets colder again.

    I do have a coolant leak “suggestive of water pump” according to garage when I had previous work done and am looking to get this sorted.

    I’ve had the car since April and haven’t noticed any improvement or deterioration.

    Is it likely that this is related to the coolant leak? I can’t think of much else since it will reach full temp but only when the engine is at proper operating temps. The AC works perfect for cold settings.
     
  2. Legojon

    Legojon I only wanted a remap
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    Sounds like the thermostats not opening at the right temperature.
     
  3. Damo H

    Damo H Because I was inverted...

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    Possible cause yes, as the engine coolant is what is also used to heat the interior I believe. So if there is an airlock in the system due to coolant loss, then the heater matrix may not just be full of an airlock.

    I'm sure someone more technical will confirm if I'm wide of the mark.
     
  4. ben

    ben Active Member

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    And this would be fixed by a water pump replacement?
     
  5. Damo H

    Damo H Because I was inverted...

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    Or what he said lol

    Thermostat is part of the water pump housing.

    I'm sure I've read on here that you can replace the thermostat by itself, but a new pump comes with the thermostat. Something about someone not being able to get the thermostat as part of warranty quickly enough so a dealership having to get permission to take it off a pump they had in stock.
     
    ben and Legojon like this.
  6. ben

    ben Active Member

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    Thanks for your responses. It seems that my thoughts are in line with your ideas. Hopefully this reflects when I finally get round to sorting it out. At the min it’s just like 100ml every 1000 miles or something but looking to get DSG and Diff serviced so will probably get it sorted then, prior to winter!
     
  7. ben

    ben Active Member

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    Just had thermostat housing leak repaired. Issues remain. Any ideas?
     
  8. BigJase88

    BigJase88 Jase

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    Air lock in system
     
  9. ben

    ben Active Member

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    How would I sort that out?
     
  10. ben

    ben Active Member

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    Or confirm it being the issue? :)
     
  11. BigJase88

    BigJase88 Jase

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    Start engine from cold with coolant reservoir cap removed and compress radiator hoses to get any trapped air out of the system. Have heaters on hot while doing so.

    that should force any trapped air out of the system

    obv replace coolant reservoir cap after doing so
     
  12. BigJase88

    BigJase88 Jase

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    Similar scenario to bleeding radiators in the house.

    coolant reservoir cap is top of the system so removing that will let any trapped air escape
     
  13. BigJase88

    BigJase88 Jase

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    Did you ever replace the thermostat itself?

    the thermostat could be stuck open which would then circulate the water round the radiator at all times thus taking forever to get any heat into the system and unable to maintain 90 degree’s water temp.

    will also be effecting your mpg if that is the case
     
  14. ben

    ben Active Member

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    I had it done at a JCT600 dealership
     
  15. ben

    ben Active Member

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    MPG isn’t great or terrible -
    Get between 26 and 31 so assume that’s normal
     
  16. ben

    ben Active Member

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    So the problem was present before and still remains, could be an air lock I guess caused by initial leak. I’m scared it’s the matrix you see Cos that’s another pricey job and I’ve already spent quite a lot since buying this car in April (4x fuel injectors, fuel pump, thermostat.. plz no more)
     
  17. BigJase88

    BigJase88 Jase

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    You find most dealerships employ school leavers and they work from computer slideshows of how to do a job. Very rarely you will find a real mechanic at any of them.

    I suspect air lock would be rotten luck for a matrix on what should still be a relatively new car
     
  18. ben

    ben Active Member

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    Aye - my pals partner works in sales dept so got diagnosis, DSG service and stat replacement for £500 which I thought was a decent price as some places quoted me up to £850 for pump replacement alone!
     
  19. ben

    ben Active Member

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    They reckon a seat master tech looked at the car but they’ll always tell you rubbish like that haha
     
  20. BigJase88

    BigJase88 Jase

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    Aye its always a master tech.

    had the same rubbish at a VW garage once they somehow managed to smash a wheel bearing. Personally i think the car fell from a height off a ramp but was assured the “master tech” did the job. Asked to speak to said “master tech” and when he came out he would he lucky if he was 20 years old. Do not believe their nonsense. If he was a master tech he would have his own garage
     

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