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tdi overheating

Discussion in 'A3/S3 Forum (8L Chassis)' started by egesford, Jan 21, 2012.

  1. egesford

    egesford Member

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    my tdi 110 is over heating when under load at low to medium revs, it cools down quickly if i change down a gear and keep it at high revs. ive changed the thermostat and flushed the coolant but has made no difference. Its going in the garage on monday and the mechanic reckons it might be the head gasket but im not losing any power, the coolant looks clean, as does the oil.
    Im thinking water pump, anyone think of anything else it could be?
     
  2. beachbuggy

    beachbuggy Well-Known Member

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    Head gasket, common failure on the tdi'a normally hg fails around piston 2 water galley, so when under load hot exhaust gas blows into the water system. Only symptom will be over heating and pressurised coolant bottle. As no oil passes , coolant will look ok and no loss of oil or coolant, but you will smell exhaust gas in the coolant bottle.

    Will they are changing the hg, make sure they clean the inlet and egr for you.
     
  3. Broken Byzan

    Broken Byzan Photographic Moderator
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    If you are not losing water then Water pump would be my guess too
     
  4. egesford

    egesford Member

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    yeah the mechanic said he could check for this using a chemical solution in the header tank, which he says is about 90% accurate
    the car has 165000 on the clock and is on the original hg and water pump
    im hoping its the water pump as ive spent **** loads sorting this car out, since ive had it (6 months) its had new clutch, flywheel, wheels and tyres, interior, starter motor, central locking pump, stereo, seat belts.
    planning on a remap next few weeks so i suppose getting the head gasket done wouldnt be a bad idea at this mileage anyway.
    anything else worth doing while the heads off? assuming it turns oiut to be the gasket
    it will be getting new water pump cam belt and tensioner regardless

     
  5. towcestervag

    towcestervag Member
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    chemical block tests dont work very well on diesels
    i would have it hydro carbon checked personally
    check water pump first remove thermostat to get to back of pump and see if the impellor turns
     
  6. colicabcadam

    colicabcadam Guest

    water pump 99%

    if you rev it more and it cools down it wont really be anything else, i bet the water pump has lost a few blades on the impellar so when it spins faster (higher reving engine) it makes up for it
     
  7. egesford

    egesford Member

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    thats what im thinking, someone said these had crappy plastic impellers as standard so hopefully it will be this, been quoted £250 for cambelt and water pump inc parts and labour which i thought was cheap
     
  8. a3tdi2001

    a3tdi2001 Member

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    Does sound like the waterpump, it's done well to last so long. It's well worth doing a thorough flush of the system and replacing with fresh G30 and deionised water as well.
     
  9. egesford

    egesford Member

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    yep it was this exactly.

    having full top end rebuild, cambelt kit, water pump.

    This is going to be expensive, would have probably just scrapped the car normally but since ive already spent hundreds on it in the last few months may as well carry on now.

    on the plus side since pretty much everything on the car has been replaced, should be able to cope better with planned mods.

    Remap first, then what?????

    is this worth getting?
    eBay - The UK's Online Marketplace
     
    #9 egesford, Jan 24, 2012
    Last edited: Jan 24, 2012
  10. beachbuggy

    beachbuggy Well-Known Member

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    Unfortunately it's not the parts that are expensive it's the Labour, I would say 6-7hours.. Get them to clean the Inlet manifold, fit an EGR delete and make sure they replace the turbo feed pipe as well, as it's almost impossible to remove it without bending it a little.

    The job its self isn't that difficult its just a lot of unbolting to get the head off. And make sure they don't skim the head, I know it sounds odd but on the TDI's you'll cause more problems than if you just left it!
     
  11. egesford

    egesford Member

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    Mmmm. Head has been sent off for to be skimmed already, thought of would b ok if a thicker gasket was used? The Guy doing it is vag specialist from Poland, really good and really cheap, but got a waiting list of about 6 weeks. What problems can skimming the head cause?
     
  12. beachbuggy

    beachbuggy Well-Known Member

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    When you skim a tdi head, as it's flat you leave the valves protruding more. If you do nothing the valves will touch the piston as the cr is so high. Either you have to Lower the valves by the same amount as the skim or as you said put a thicker hg on. How ever the thicker hg will be much thicker than the light skim and thus reducing the cr and running problems. It's just a point to note.
     
  13. egesford

    egesford Member

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    he did say something about valves but i wasn't listening by that point too busy thinking **** **** ******** **** this is going to empty my my bank account. i'l have a word with him tomorrow and see what the crack is
     

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