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Why is my engine cold to touch after a run?

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3 Nattie, Nov 26, 2009.

  1. A3Tom
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    A3Tom Smell my finger.

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    [Nov 28, 2009]
    The stat has to be put in a certain way around. I checked this in the haynes book when I replaced mine earlier on today.

    Its just off the vertical as you look at it if that makes sense.

    My money is on air in the system.

    T
    #41
  2. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Nov 29, 2009]
    I will give the first suggestion ago then go from their. I have blead a few systems before and it so easy if there is a bleed screw.

    It a strange problem this as the car drives fine although a few psi down on boost. The temp gauge is alway on 90 an the CC is near enough the same and the coolant level is the same but the engine is still touchable after a quick blast.

    Will give it ago in the morning and will report back.
    #42
  3. NHN
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    [Nov 29, 2009]
    Yeah but if the temp sensor/s are the warm side of the system then they would show this temp fella.
    #43
  4. pauldazzle
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    pauldazzle Active Member

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    [Nov 29, 2009]
    Absolutely, the coolant temp sensor is on the hot side. So in all likelyhood your temp gauge would read mormally.

    Nathan if you need another pair of hands to help with this pm me & we'll meet up in Cardiff somwhere.
    #44
  5. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Nov 29, 2009]
    Ye are right. The top coolant hose ( hot one in my case ) goes straight to the coolant temp sensor.

    Thanks for the offer Paul. I had a quick go earlier while it stop raining for a whole 10 min. Had the heater and fans on max with the expansion cap off but the engine wouldn't get up to 90 degrees. Going to give it another go after uni tomorrow depending on the weather. If im still not getting there I will take you up on your offer Paul.
    #45
  6. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Dec 2, 2009]
    OK well had a little go at trying to get a air lock out.

    Started the car with the cap off and heaters on max. Keep squeezing the bottom hose for a good half hour and there were tiny little bubbles come up every time I squeezed the hose, not sure if the bubbles were because I keep squeezing the hose as they were tiny.

    The car gradually got up to temp. The water wasn't bubbling or rising when I increased the rpm. Not sure what to do next.
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  7. pauldazzle
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    pauldazzle Active Member

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    [Dec 2, 2009]
    You need to squeeze the top hose too.
    #47
  8. S3 Nattie
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    [Dec 2, 2009]
    Ye I was squeezing the top hose too, it wasnt making no difference to the coolant in the tank though.

    I was thinking earlier, shouldn't the thermostat hose by colder than any other hose within the engine as it contains coolant from the radiator. The coolant from the engine is going through the top radiator hose and travelling down the radiator where it should be getting cooled down in the process, then back through the thermostat. Correct me if im wrong anyone.
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  9. pauldazzle
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    pauldazzle Active Member

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    [Dec 2, 2009]
    No the bottom hose should get hot too, when the thermostat has opened.
    #49
  10. pauldazzle
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    pauldazzle Active Member

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    [Dec 2, 2009]
    Did you notice if there was any flow back into the expansion tank?
    #50
  11. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Dec 2, 2009]
    OK. I thought as the radiator is cooling down the coolant it would be cooler than the top hose as this is coolant that as been circulating around the engine.

    Since trying to get the air locks out this morning the car seems to be emitting more white smoking than usually, wouldn't say its condensation either. Do you think I may have made more air locks lol. Why dont we have a nice and easy bleed screw.
    #51
  12. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Dec 3, 2009]
    Mate just take it to a garage and let someone do it.
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  13. NHN
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    [Dec 3, 2009]
    TBH I would empty the system as I already advised, then check the stat installation, then refill slowly let it stand for 2 hours then try again, failing that do as Dan said cause you're getting nowhere fast.
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  14. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Dec 3, 2009]
    Ye thats what im going to do. Empty the system and refill, if this doesnt fix the problem il take it to my specialist.

    Quick question, where to is the drain screw on the system and how much coolant/G12 should it take to refill.

    Thanks Nathan
    #54
  15. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Dec 5, 2009]
    Ok, for the first time im glad I burnt my hand lol. Got the bottom hose to get hot, hopefully it stays like it. I will keep checking it over the next few weeks.

    If anyone else is having the same problem, cold thermostat hose, all you have to do is let the engine warm with the expansion cap off till the fans kick in which should mean you are now getting hot coolant circulating around the engine with no air locks.
    #55
  16. pauldazzle
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    pauldazzle Active Member

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    [Dec 5, 2009]
    Glad you got it sorted:icon_thumright:
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  17. NHN
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    [Dec 5, 2009]
    So you're telling me you didnt remove the coolant at all just left cap of, guess could of relieved some pressure huh, oh well one to remember & must have been air lock then
    #57
  18. S3KO4
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    S3KO4 Member

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    [Dec 5, 2009]

    is the boost back on then?
    #58
  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Dec 6, 2009]
    If you haven't done a full flush then you may find that you have only temporarily cleared the air lock by removing the header tank cap. Keep a beady eye on it!
    #59
  20. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Dec 6, 2009]
    Ye going to keep an eye on it. I rang my specialist and they say thats what they do when they do a stat or head gasket.

    I may change the coolant sensor soon just to rule it out. My gauge aint spiking as high lately and its not as smooth when on boost.
    #60

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