Block Tester / possible coolant loss into cylinder?

Discussion in 'Engines' started by Trev16v, Nov 29, 2008.

  1. Trev16v

    Trev16v Paid Member Paid Member

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    I've used a Block Tester kit to determine whether engine gas is getting into the coolant on my 16V G60. It's the type where you put a small quantity of dark blue fluid into a glass tube; you then tightly wedge the tube into the top of the header tank and squeeze the rubber bulb at the top for a minute to draw gas into the tube from the coolant.

    After several minutes the fluid turned pretty much yellow; possibly more green-yellow. But took longer to turn colour than the manual suggests you should do the test for, which is just one minute.

    My question is this: If you use the Block Tester for several minutes (i.e. longer than the one minute), is it quite possible for the fluid to start turning yellow even if your engine and coolant are fine?

    I do suspect a problem with the engine. When I first start the engine from cold or reasonably cold there's nothing visible from the exhaust; however, after running for a few minutes, white smoke (or steam?) starts appearing and it gets worse and worse to the point where it's very excessive and water drips from the exhaust (I collected a bit in a jar). It gets to the point where it'd make an ideal club smoke machine.

    I think the coolant is dropping; I think the header tank level goes down by one or two millimetres each time I start up and completely warm the car. But need to continue monitoring it to be sure about this.

    This engine is completely rebuilt and must have only done twenty miles or so in total.

    There is no misfiring at all.

    The spark plugs all looked the same yesterday. No sign of either having been steam cleaned. What's really odd is that I took all the plugs out again today and they all looked MUCH blacker than they did yesterday, and the idle AFR seems a little richer than usual (down to 12.x) at idle; this is odd because I've not touched the fuel VE map at all at idle lately (but this is something I need to investigate). So (um, sorry to have really gone off the original topic here!) I wondered if the excessive white steam could be a result of it idling too rich.

    I can upload some videos and pictures shortly.

    Trev
     
  2. Trev16v

    Trev16v Paid Member Paid Member

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    Here's the extent of the colour change:

    [​IMG]
     
  3. Trev16v

    Trev16v Paid Member Paid Member

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    Last edited: Nov 29, 2008
  4. Trev16v

    Trev16v Paid Member Paid Member

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    Repeated the test today and it still goes yellow after pumping the bulb for about a minute or so.

    Tested the Block Tester on another car just as a confidence check, and the fluid remained totally dark blue.
     
  5. Trev16v

    Trev16v Paid Member Paid Member

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    Just wondering if anyone has any opinions on this? Is the Block Tester conclusive? Could there be any other condition, other than a fault with how the head gasket it sealing, that could cause this result from the Block Tester? I don't mind lifting the head to investigate the head gasket if I need to, but I just want to be really sure the Block Tester can't be telling lies. I did try the Block Tester on another car and on that car the fluid remained blue, so I am confident it's nothing to do with how I did the test.

    The problem is that I have a couple of mates who insist that it's a condensation issue because I have never properly taken the car for a long, long drive to fully warm up the exhaust system; and therefore each time I run the car I'm just getting more water into the system. But it's a bit catch-22: I don't really want to be running the car for ages if there's a genuine problem.

    Got a new ABF head gasket sitting here from VW ready to go on.

    I also have the correct torque figures for the ARP fasteners as advised by ARP themselves. There's a possibility that I didn't apply the correct torque to the head studs originally, so as a starting point I may just take the rocker cover off and try to determine what torque I did them to.

    Trev
     
  6. Mike_H Forum Addict

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    I think those block testers are turned by exhaust gases, rather than condensation issues, so I don't see how that could be the source of the problem. The condensation would explain the steam at startup though - you've probably got little puddles of it in the bottom of your exhaust boxes.

    Have you re-checked the torque of the head nuts since you built it?

    I guess it could be worth doing a re-torque, then emptying out the cooling system and refilling with plain water for a retest. Easier than taking the head off.
     
  7. gazw Forum Member

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    The block tester detects combustion gases in the coolant, it works on diesel (turns green) and petrol (turns yellow). Condensation will not effect it in any way. I use a block tester on a weekly basis and have never known mine to be wrong. Sorry!!
     
  8. Trev16v

    Trev16v Paid Member Paid Member

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    Gents,

    Again many thanks, very much appreciated - it's good to have confirmation that I definitely do (possibly) need to go ahead and investigate. It's especially good to have confirmation from someone who uses one frequently.

    I didn't explain very well in that last post, actually: what I meant was that my friends are trying to convince me that the condensation is causing the steam from the exhaust, and that this is the only reason and there's nothing wrong with the engine. But the Block Tester is clearly telling me otherwise. I'm glad I got it off eBay now!

    I shall report back!

    Trev
     
  9. Mike_H Forum Addict

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    Your friends are probably right about the condensation, but it sounds like you have another problem too.

    Can you smell any gas in the header tank too?
     
  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    is it a 2 litre now then trev? should go like the clappers [:D]

    As for the test, have you totally drained & flushed the coolant system recently? Maybe theres some residual crap in there effecting the readout?
    The level will drop a little I'd have thought due to pressure, but then it would expand a bit when hot? Dunno :lol:
     
  11. Trev16v

    Trev16v Paid Member Paid Member

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    It's a 1.9 :)
     
  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    awesomes! at least if it is a head gasket it wont be so bad to clean off the mess, fibre gaskets are a mare to clean up after but metal ones come off nice & clean :)

    I found your other thread and had a read of the last posts, I've noticed mine releases plumes of white smoke in the mornings when cold, but I'm 99.99999% sure there is no head gasket issue. I also wouldnt worry about the headgasket alignment, once you get the bolts in it wont go anyhere, its more just to keep the damn thing still when you juggling the head about.

    I've done hg on both a MK2 1.6 and 1.3 polo and neither had the alignment stud, gasket sealed itsen no problems, though I realise its a far cry from a 1.9 G60 16v :lol: I dont recal the 2e block I did 2 head swaps on having the alignment stud either? Maybe I'm just getting old :lol:
     
  13. Trev16v

    Trev16v Paid Member Paid Member

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    Thing is, a metal ABF gasket should be as tough as anything shouldn't it? But I guess that means nothing if there's any possibility that I have not torqued the ARP fasteners properly or done some other assembly error.

    Did you see those YouTube videos again John? Seems pretty bonkers how much is coming out!
     
  14. Trev16v

    Trev16v Paid Member Paid Member

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    Right gents, I wasn't sure how I should go about checking the ARP stud nut tightness, so what I did was to set my electronic torque gauge on 'peak' and I very slowly and gradually increased pressure to the wrench (tightening the nut) until there was a 'crack' or movement.

    The torque values (in ft lbs) that I reached for the nut to 'crack' were as follows (listed in the order of correct torque sequence, i.e. bolts 1 to 10 as shown in Haynes):

    71
    69
    78
    64.8
    78.5
    85.3
    72.7
    64.5
    73.1
    72.7


    The actual correct torque as instructed by ARP is 80 ft lbs with ARP moly lubricant (which I used).

    What do you guys reckon? Given that these were tightened a few years ago and that the engine has temperature cycled, is it probable that I originally only tightened them at 60 ft lbs or something? Or lower?

    Thing is, it seems like they're not that low and I know they're not ideal but I'd be surprised if the torque I used would give problems at such an early stage.

    Thoughts? :)
     
  15. vrbanana Forum Junkie

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    The metal head gaskets are less forgiving for any sort of marks and distortion in the head, both surfaces must be spotless and dry, I’d always have the head skimmed, especially if it’s had a steel gasket on before as they leave slight rings around where the gasket seals the cylinders. Once both surfaces are clean, dry them with a solvent.

    The chemical test looks conclusive, condensation or antifreeze vapour won’t alter the colour unless the coolant actually mixes with the chemical
     
  16. rubjonny

    rubjonny Administrator Staff Member Admin

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    I hadnt yet as I'm at work + its blocked, but after lots of faffing I got the vids downloaded and on me work PC, then some codecs installed. It does look pretty bad, and I just re-read you post and you say the smoke doesnt appear till the engine gets warmed up a bit, mine it the opposite its smokey when cold but then clears up when hot :(

    What I meant with the metal gasket I doubt its an alignment problem :)

    If it was me I would think about doin em all up again to 80, see where that gets you. Not got anything to loose :lol:
     
  17. MUSHY 16V

    MUSHY 16V Moderator Staff Member Moderator

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    nothing to lose
    re torque them then as mike sed drain and flush the coolent
    and test it again
    i dont no if it's just the photo but when the block was decked
    the finish looks a bit on the ruff side
    was it that ruff
     
  18. Trev16v

    Trev16v Paid Member Paid Member

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    Banana: The head and block were skimmed originally; but from what you say I suppose that I would have to take the head for yet another skim then if I end up changing the head gasket. :(

    If there is any mixing (which Block Tester says there is) then would I definitely see evidence of it on the head gasket, no matter how slight the leak is?

    John - thanks for taking a look mate. I'll try that tomorrow morning and see how it goes.

    Mushy 16V: I don't recall the block face being rough. I think it's just the photograph. I recall it having a nice smooth machined surface.
     
  19. rubjonny

    rubjonny Administrator Staff Member Admin

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    I shall cross me fingers for you :)
     
  20. MUSHY 16V

    MUSHY 16V Moderator Staff Member Moderator

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    if it was my i would blue the head agenst the block to see how flat the block is
    with engineers blue


    [​IMG][​IMG]
     

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