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Thermostat changed..the plot thickens, or does it?? Help needed.

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Jason-Con, Jan 23, 2010.

  1. Jason-Con

    Jason-Con Member

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    OK well this morning i got the thermostat changed on the A4 tdi 1.9. Now the guy that did the job changed the stat then left the car running , the temp gauge did not move from its original position. He then proceded to pull off the expansion tank hose where no water was coming out. Long and short of it was he told me it looks like the waterpump is done and needs changing as the top hose is cold. So i drive off not happy thinking ive just bought a dud car and just like magic the termp gauge reaches 90 and stays at 90. The top rad hose they said was cold due to the waterpump working is now warm as it should be and everything seems perfect.

    • Now in the back of my mind im thinking i need a waterpump , but do i?
    • Have they dioginosed the problem correctly (bearing in mind i know these guys)?
    • Has the waterpump developed a intermittant fault ( but i was under the impression with it being belt driven it either works or not)
    • Could it be a airlock issue?
     
    #1 Jason-Con, Jan 23, 2010
    Last edited: Jan 23, 2010
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  3. J7USS

    J7USS Shuddup Foooool!!

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    Sounds like you had an Air lock judging by what you said. You need to keep an eye on your water level. Have you had to top the water up since you got back??
     
  4. quattrojames

    quattrojames Moderator
    Staff Member Moderator Audi Avant Owner Group Audi A6

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    Hi Jason, I'm no expert there, but can offer the following:

    • Water pumps will not have intermittent faults, any failure normally manifests itself with the engine overheating when being worked hard.
    • Have you considered the temp. sensor?
    • If it's working fine now it sounds like it was probably an airlock, has the water level dropped in the header tank at all?
    I would just run it carefully for a couple of days and keep an eye, hopefully it will be ok ;)
     
    #3 quattrojames, Jan 23, 2010
    Last edited: Jan 23, 2010
  5. simon.m

    simon.m Active Member

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    just wait and see how you get on with it mate if it does it again then worry. im not sure if
    your pump can have a interminttan fault it works or dont. may have had an airlock as you say and just needed a run to
    clear it have a look see if you need to top up the water if so airlock
     
  6. Jason-Con

    Jason-Con Member

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    Im going to check the level now. I wont open the tank. Ill be back in a sec.


    OK the level is now just below the min. Should i just top it up?
     
    #5 Jason-Con, Jan 23, 2010
    Last edited: Jan 23, 2010
  7. simon.m

    simon.m Active Member

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    i would and then run it then let it go cold and look again
     
  8. Jason-Con

    Jason-Con Member

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    Cool, Would the airlock stop flow of water to the top pipes on the rad?
     
  9. yendall24

    yendall24 Member

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    hi mate how long did the guy at the garage run it for diesels warm up a lot slower than petrol engines and in this weather a diesel left ticking over will take an age to warm up also bare in mind that the temp gauge does not register until 60oc so i dont think there was ever a problem with the water pump or air lock it just needed driving to acheive 90 oc
     
  10. Jason-Con

    Jason-Con Member

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    The guy had it running for 30 mins, and the top hose was cold. the secont i take it out for a bit of a blast it went up to 90 and stayed there, I got the car home and checked the level and it was below the min...bearing in mind the garrage topped it upto max before i left i can only put it down to an airloc. But should the top hose get hot on tick over?


    Bottom line is ive been driving it around town for 30 mins and the needle has stayed at 90. Does it look like im in the clear?
     
  11. vinesh

    vinesh Member

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    I recently had my thermostat changed and I had an airlock as well (Leics Audi)

    I left my car ticking for 45mins and the temp did not move. I spoke to my local mechanic and he squeezed the bottom pipe to remove the air lock after this I went for a long drive. The airlock was removed and the car now stays at 90.

    I think there is nothing to worry about.

    If it was the waterpump then it would have over heated.
     
  12. quattrojames

    quattrojames Moderator
    Staff Member Moderator Audi Avant Owner Group Audi A6

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    I'll second that.
     
  13. Jason-Con

    Jason-Con Member

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    Thanks guys, ill try to get it out of my mind but i think when i got the spare cash im going to change the pump,timing belt and pullies just in case.
     

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