mikeb
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| posted on 2/7/09 at 08:56 AM |
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Bubbles in expansion bottle = Head Gasket?
I have just filled the cooling system in my TVR.
It has a swirl pot so isn't quite the same as the standard capri/sierra layout.
There is also an expansion tank that attaches to the top of the swirl pop.
I noticed I have a slow but steady stream of bubbles into the expansion tank.
The engine has had a light refurb by the previous owner with new gaskets etc.
Is this normal, could it be a bleeding issue or is one of the head gaskets leaking air?
Cheers
M
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wilkingj
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| posted on 2/7/09 at 09:02 AM |
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Hmm... Well IMHO it could be the swirlpot doing its job. That is to remove the air bubbles in the water.
However, once it has got them all out, you shouldnt have many bubbles after that.
Have you just refilled the water system, ie the possibility of an airlock or bubbles that are now coming out of the system via the swirl pot when you
run the engine?
Is the colour of the water the correct colour? ie has it discouloured the antifreeze?
Is there any oil floating on the water
Is there any water in the oil (check the dipstick)?
I am sure that others will add to the list of check points
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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mikeb
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| posted on 2/7/09 at 09:48 AM |
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This was the first proper warm up the engine has had after filling the coolant system up. It just has plain water in at the minute as I wanted to leak
test it and not waste a load of antifreeze.
I wasn't 100% sure which was the send return to the heater matrix so they could be the wrong way round?
Think the dip stick is fine.
I have had this on other cars, my old scirocco and sierra use to do it. but was never 100% that it was ok.
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Dusty
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| posted on 2/7/09 at 11:26 AM |
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Agree it's probably normal. Run up to temperature with the rad cap off keeping it topped up. Let it do a couple of fan cycles the final top up
and cap back on. That should let any air clear out.
If you are very worried re head gasket leak then Frosts do some stuff that will detect combustion/exhaust gas in the rad. It's a blue liquid
that changes colour if the gaskets gone.
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britishtrident
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| posted on 2/7/09 at 11:37 AM |
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Water contains dissolved oxygen and other gases from the air when heated these gases are forced out of solution.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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cd.thomson
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| posted on 2/7/09 at 12:38 PM |
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noway would heating water force dissolved atmospheric gases out of solution and even if it did then there wouldn't be enough to give a steady
stream of bubbles.
unless by "plain water" he meant "soda stream dandelion and burdock"
[Edited on 2/7/09 by cd.thomson]
Craig
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mikeb
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| posted on 2/7/09 at 02:09 PM |
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all interesting, anyone else experienced this, hoping its just a bleeding issue, but did have it running for about 5 minutes and they were still
coming.
M
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Bluemoon
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| posted on 2/7/09 at 02:28 PM |
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My bet is an airlock; probably go after a while; if not I would then start worrying..
Personaly I would turn the engine over by hand before using the starter next time in case water has got into a cylinder whilst standing (unlikely
though) ..
Dan
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britishtrident
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| posted on 2/7/09 at 07:14 PM |
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quote:
Originally posted by cd.thomson
noway would heating water force dissolved atmospheric gases out of solution and even if it did then there wouldn't be enough to give a steady
stream of bubbles.
unless by "plain water" he meant "soda stream dandelion and burdock"
[Edited on 2/7/09 by cd.thomson]
Actually no, as a former steamship engineer I can assure you that heating water and then storing it close to boiling point is the standard way of get
disolved oxgygen out of water, the closer water is held to boiling point the more disovled gas comes out and the more quickly it comes out. -----
this can be seen (and heard) in a domestic kettle a steady stream of gas bubbles are expelled before the water can start to boil.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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cd.thomson
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| posted on 2/7/09 at 07:40 PM |
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youre right that the solubility of gases decreases as the temperature of a liquid increases:
http://antoine.frostburg.edu/chem/senese/101/solutions/faq/temperature-gas-solubility.shtml
but your theory seems based on an urban myth (the kettle thing)
http://ilovebacteria.com/boiling.htm
heating will force atmospheric gas out of solution initially but the concentrations and therefore the vapor pressures are negligible. Certainly no
bubbles will form and solubility never decreases to zero. In fact solubility begins to rise before normal boiling point.
everyone knows science pwns engineering
[Edited on 2/7/09 by cd.thomson]
Craig
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