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This Looks "Wrong" To Me. What Do You Think?

Discussion in 'A4/S4 forum(B5 Chassis)' started by tux, Jun 19, 2010.

  1. tux
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    tux Member

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    So I finally spent some time on the car and got the drivers side head off. Although I can see no obvious point of failure on the head gasket (cylinder 3 was low on compression) it doesn't look right to me.
    It seems that cylinder two may not have been firing? Seems to be almost brand new compared to one and three. Although the head shows an even layer of carbon just like the other two cylinders.
    Also it looks like there is some corrosion going on (in the red circles), is this acceptable, or is the block scrap?

    Thanks for any input guys.

    [​IMG]
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  2. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    hmm the middle one probably has been injesting water causing the steam cleaning effect, and the far right one doesnt look right to me.

    Is that a chunk missing? or shadow/reflection?
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  3. tux
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    tux Member

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    No, its a small "puddle" from where it filled with water when I took the head off, because I hadn't emptied the cooling system properly. [​IMG]
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  4. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    Cool, so which is suffering compression loss dude?

    I would say the middle one has been leaking/sucking water into the cylinder, it's possible that the cylinder that has the compression loss is also leaking into the faulty cylinder....
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  5. Matt82
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    Matt82 Active Member

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    middle one has obviously steam cleaned itself. any chance there is corrosion under the gasket which allowed the water in?
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  6. Tyler Owen
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    Tyler Owen Member

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    Looks like incomplete combustion in the number 2 cylinder and the unburnt fuel has worked wonders on cleaning the cylinder .
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  7. tux
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    tux Member

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    Hey, thanks guys.
    I have done a little more investigation now. The gasket is off and there is no sign of corrosion underneath. I have checked the head with a steel rule (not very accurate I know!) and it seems to be flat. The gasket seems to be in very good condition to be fair. Where I circled above it seems it is the gasket that has corroded, so this could have been where water was entering cylinder two.
    The compression test readings suggested that cylinder three was slightly down on compression, but having said that, I did use an el cheapo tester so it probably wasn't that accurate.
    I'm feeling a bit more confident now, so I reckon I'll strip the other side and make sure it is no worse and then clean up and bung it all back together with fresh gaskets/bolts etc. New water pump, thermostat, timing belt kit and serpentine belt and idler should complete the job and hopefully the job will be a good 'un. If not, then I'll probably swap out the lump and be done with it.

    thanks again for your input guys. Its much appreciated.
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  8. millsy
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    millsy Member

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    on the right cylinder,is that an oil build up or damp carbon?if its oil,was there any sign of a leak on the gasket?if not,might be an idea to do the rings while its all stripped down?
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  9. tux
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    tux Member

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    Its just damp carbon, where it got filled with water from the head.
    There was no oil being burned and no smoke before the strip down so I think the rings should be OK. :sm4:
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  10. millsy
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    millsy Member

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    thats good news then.
    re; the corrosion on gasket,once all parts are stripped off,flush all the water ways back until they run clear,nothing worse than putting it all back together,only for some **** to be left in there to start the problem all over again!
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  11. tux
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    tux Member

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    Will do. Thanks for the tip, I wouldn't have thought of that. :beerchug:
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  12. millsy
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    millsy Member

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    glad to help mate,good luck with other head!
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  13. tux
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    tux Member

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    Alrighty then! Not had a heap of time to work on this over the last month, I'll spare you the excuses, but today I got it finished. Yippee.
    Heads on, belts/tensioners etc changed, front panel back on (broke two, torx 45 sockets doing that which miffed me a bit!) and radiator filled. Heater matrix pipe opened until water came out of the little hole. Turned the key and it started first click. Result! Ran a bit rough for a few seconds and then settled into a nice idle. Waited for it to reach operating temp and ....... its just the sodding same! Not getting even remotely warm air through the demisters either.
    I'm really at a loss now as to what could be wrong. Can anyone suggest anything? I will concede that I didn't change the thermostat (oversight on my part) but as the top rad hose is getting hot I'm tempted to say that the thermostat is opening.
    All ideas greatfully recieved.
    Thanks guys and gals.
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  14. jcb
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    jcb Active Member

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    pull the pipes on your heater matrix and reverse them, you may need to extend them with a bodge. looking at your water galleys I would say it is blocked.

    doing that is a quick way to dislodge any buildup. the down side is it is still in the system. alternative is pulling the matrix pipes and flushing them out with a hose before re-attaching the pipes
    #14
  15. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    What exactly is the doing when you say its exactly the same?

    On the 1.8T, the stat is in the bottom hose, so its perfectly possible for the top hose to get hot, but the stat never open and the engine overheat... V6 may well be the same.

    In the above pic, you've highlighted deposits in the water galleries of the block, did you clear all these out, or leave them blocked up like in the pic?
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  16. tux
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    tux Member

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    Apologies guys, I thought I had explained my woe in the first post, but it seems not!:redface:

    There has never been hot air coming from the demisters, the car would "use" the water in the expansion tank in about 25 miles and I have never been able to bleed the cooling system properly. There was a head gasket failure (car was blowing steam from the exhaust, confirmed by a sniff test) so I took off the heads and replaced the gaskets. I got a mechanic friend (who unfortunately lives in Birmingham so isn't around much) to check the heads and he was happy that they weren't warped.
    The water galleries were all clear when the heads went back on. As yet there doesn't seem to be any steam from the exhaust, but I still cannot bleed it up properly and I still don't have warm air.
    In fairness it does feel as though there is no water in the top hose when squeezed.
    I have just ordered a new thermostat and I will change it out. Only missed it due to a delivery cock up from my parts supplier. At least its only the front of engine stuff that has to come off to do it, not the heads again.

    Thanks for your suggestions so far guys, its much appreciated.
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  17. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Does your car have climate control? If so, it could be a broken vent flap motor?

    Do the heater matrix pipes get hot, and what does the temperature guage do?
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  18. Audidave
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    Audidave Member

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    have you opened the allen bolt bleed screw on front of engine my had loads of air in it, right hand side when looking from front of engine under coils only a thought!
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  19. tux
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    tux Member

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    No climate control (not even air-con, I'm poor dontcha know! lol). Heater matrix pipes get hot (still cool enough to touch though) but again they don't seem to be "full" of water. Temp gauge stays steady at 90 degrees as always. Having said that I haven't yet run it for more than about 15 or 20 minutes at a time.
    If I leave the cap off the expansion tank, every so often it spews out water, almost as if it is boiling up.



    there is a bleed screw on the front of the engine? Tell me more! I was only aware of the bleed hole on the heater matrix pipe.
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  20. Audidave
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    Audidave Member

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    there is a allen headed bleed screw on a steel pipe just to side and below coil pack on the 2.8 30v down by power steering pump pully under plastic engine cover may be the same on 2.4
    http://etka.auto2.ru/epc/cat/vw/BO/2005/403/
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Boiling over when the cap isnt fitted is completely normal.

    The coolant will get to over 100c before the fans kick in to try to bring it down again, so if the system isnt pressurised then it will boil.

    Sounds like your onto something with the bleed screw though!
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  22. millsy
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    millsy Member

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    you have an air lock mate.wait till its cool and top up header tank,undo 3 retaing screws and support tank as high as possible with out kinking hoses.as already mentioned,remove allen key headed bolt(just to the right of coil pack) and wait till water runs clear of trapped air,replace bolt,tank and top up coolant.start the car,fully turn on heater to hot and to the windscreen.time for a cuppa while it warms up.would recomend not fully tightening cap down for a day or two,which will allow exit for any air still trapped
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  23. tux
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    tux Member

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    Well, its been a while. Been busy with, err, stuff.

    Anyhoo. It seems I was being a bit of a muppet :wacko:. Had a look at the Audi again this weekend now that I have a little free time and it seems I didn't replace the hose clip after I pulled the hose to the heater matrix back to bleed the system. This was water tight when the engine was off, but as the car got up to operating temp with a little pressure in the system it was allowing water to escape. Clip back on and the problem is solved. Steam from the exhaust was just residual water/condensation from the original blown headgasket problem so all is now good.:applaus:

    Chucked it in for an MOT this morning as it expired while it was having "issues" and it flew through without so much as an advisory. Result.

    Anyway, despite the fact that I shouldn't be let loose with the spanners I got there in the end. So thanks everyone for your help and input. Have a virtual beer on me.

    On a side note, 10 minutes after getting back from MOT (via the petrol station) at lunchtime, 'er indoors swiped the keys and hasn't been seen since! Bloody typical!
    #23

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