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Leon FR tdi 184 Coolant loss

Discussion in 'Leon Mk3 (2012-2020)' started by tatters40, Mar 25, 2020.

  1. tatters40

    tatters40 Active Member

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    Hi Guys

    Can anyone help please

    Read lots on this but never really found an outcome
    In the last 3 weeks I've noticed my car has started using coolant.

    On occasions it drops from max to min in 50 miles sometimes longer say 150 miles. Today i checked it after filling to the max mark 2 days ago and it was below the min mark.

    There is evidence of coolant around the cap and sitting on the aluminium arm beside the expansion tank which i cleaned off previously and appears every time i loose coolant. Temp gauge never moves from 90.

    Any thoughts, hoping not Head Gasket

    Any new information regarding this issue please
     
  2. bgb

    bgb Active Member

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    Search 'coolant' on here and you will find all findings others have had, or are finding.

    https://forums.seatcupra.net/index....otorway-journeys-or-high-speeds.454370/page-8

    The above is great for info currently - TDI and coolant loss is usually one of the following;

    • Heater Matrix
    • Coolant system foreign body blockage (rust, casting sand etc)
    • Water pump housing/Thermostat

    there are non mechanical minded ways to possibly diagnose the above;

    • uniformed heat from all vents at high temp - if not could point towards coolant block/heater matrix block
    • spotting leaks - dependant on location, thermostat/pump - or just general crack in system
    • removing the filler cap and 'burping' the system - air lock

    A good rated independent will hopefully be cheaper and more efficient at diagnosing than a dealer.

    From experience though, its a very frustrating experience trying to pin point!
     
  3. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Read that thread that bgb referred to. You'll see my most recent contribution. I also have a 184.

    Not everyone has exactly the same issues but you can follow a process of elimination to try to suss it out.

    If you have good coolant temp you can probably rule out water pump and t/stat for now. Having said that, the digital gauge will sit at 90 even if your coolant is anything between 75 and 98 because that's what mine did. An app that gives real time info is better. I use inCarDoc Pro.

    A blocked heater matrix is probably the first place to start. Due to SEAT (VAG Group actually) designing a heater matrix with tiny channels in it, these get blocked over time. That is partly caused by casting sand being left in the engine block and/or silicant gel from a bag in your expansion tank that splits and gums up the coolant system. The way to test this is see how much heat comes out of your vents and whether you get a big difference from passenger to drivers side. A blocked matrix tends to cause reduced heat output and differing temps on each side. You can check the temps on the pipes in/out of the matrix as well.

    If that is the problem, the coolant loss usually comes during a DPF regen. The DPF heats up to 600 degrees and does the regen. When completed it uses the heater matrix to help cool down. The car has 3 cooling systems (`circuits`) and with a blocked heater matrix it can't cool the coolant enough so it basically boils and it opens a release valve and shoots out of your expansion tank release port (just under the cap). With the car hot you don't tend to get a warning until the car has cooled overnight and the levels have dropped. Whether you do 50 or 150 miles might be less relevant as the DPF regen decides when you dump coolant.

    A matrix is about £75. SEAT want about £1000 to do it (they quote 8 hours labour to remove the whole dash). Using a workaround guide on this forum, I did it in 2 hours.

    May car was also overheating due to a faulty pump, so I've just had done:

    New w/pump (inc cam belt)
    New thermostat + housing
    New coolant temp sender
    New heater matrix
    New expansion tank (without silicant bag)

    If you get a DPF monitoring app, you can see if the coolant loss is linked to DPF regens.

    I'm hoping that yours in just the matrix. It's a known issue although SEAT won't admit to it and I had to order my matrix from Europe due to high demand in the UK!

    Quite happy to help with anything if needed but this forum has some good stuff on it.
     
    bgb and MATT RILEY like this.
  4. tatters40

    tatters40 Active Member

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    Thanks Gents, appreciated, i hear various different Heater Matrix makes mentioned and updates to the original item, any recommendations
     
  5. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    A lot of people opted for Nissens as they apparently have wider channels in them.

    Some have said it depends if your car has Denso or Valeo matrix. Mine has a Valeo (2014 FR184 ST CUPA engine code). I chose to replace like for like. Apparently - the original Valeo has the original A version and a newer version in later models is a B.

    Tried to check if the new one I got was the upgraded B version but couldn't tell. Either way, it's new and so much better than the blocked one.

    This web-site is pretty good for getting the right part.

    https://www.autodoc.co.uk/car-parts/oem/5q0819031b

    I actually bought mine from these guys, but they might be the same people:

    https://www.buycarparts.co.uk/valeo/7665313

    From what I'd found on-line when I was looking, 5Q0 819 422 A for Valeo and 5Q0 819 422 for Denso or Nissens 73980. Having said that, the OEM number for the one I bought was (5Q0819031).

    Happy shopping!
     
    #5 Brian Gordon-Stables, Mar 27, 2020 at 9:03 AM
    Last edited: Mar 27, 2020 at 9:16 AM
  6. tatters40

    tatters40 Active Member

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    Thanks guys, i've tried everywhere i know in UK for one of these, even phoning Nissens in Coventry to check stockists, nothing available. Seat dealers are closing from tomorrow. Every review of the Autodoc site is worryingly bad (based in Berlin)
    Brian, you had a good experience purchasing from these, how long was delivery mate?

    many thanks
     
  7. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Mine came from buycarparts, although I suspect that they are the same business as autodoc.

    Bought on the 6th Feb, dispatched on the 7th and arrived on the 12th.

    This was before the #lockdown, so really don't know current lead times.

    Probably worth a punt as nothing in the UK is likely to change for a while?
     
  8. tatters40

    tatters40 Active Member

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    Thanks again Brian - top man
     
  9. ZK_FR150

    ZK_FR150 Active Member

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    I believe they are the same guys as the website and format is the same.

    In regards to Autodoc I've ordered a few times from them although it might take a week or 2 have no complaints with service and a lot cheaper than places here.

    Again with covid-19 going on I'm not sure what the delivery time will be like but just contact them and see what they say.

    Eurocarparts are showing in stock for mine 150 TDI for a Valeo one £220 can't think it wouldn't be the same part for 184 tdi, although that's quite expensive to how much they should be.

    Hope you get it sorted
     

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