harrisp
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Registered: 15th Dec 07
Location: Derbyshire
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I have just done the headgasket on my cora sport and as soon as it got up to temprature it overheated, it boils over without the cap on even though the temprature guage says 95 ish.
I checked the head with a steel ruler and a feeler guage and it seemed fine so is there anything else it could be or what should I check before I take the head off again?
[Edited on 25-08-2009 by harrisp]
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DaveyLC
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A 'steel ruler' or a straight edge?
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harrisp
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a steel ruler.
Just would be weird if the ruler was bent the same way as the head if it was warped.
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harrisp
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Just thought, I am ok blanking the coolant pipe off that goes to the throttle body arent I?
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harrisp
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Compression test results are,
190 200 210 200
Only done quickly when cold but will warm it up and do it again.
[Edited on 25-08-2009 by harrisp]
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harrisp
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Compression when warm is 205 across all cylinders
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alan-g-w
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Compression test isn't a way to tell definetely that the HG is away. All it'll tell you is if it's gone between each cylinder, not the 'outer' edges.
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harrisp
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But if it was gone surely it would lose compression as it it would be leaking out somewhere?
The car is basically overpressurising the coolant system
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alan-g-w
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If it was leaking out the sides you'd be able to hear it running like a bag of shite.
So if if it wasn't leaking out the edges, but you suspect the HG is away, you'd do a compression test to find out if it was leaking between cylinders. That's my limited understanding of it anyway.
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harrisp
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I really dont know whats up with it, had a new head gasket etc fut still dont know whats up with it, maybe a crack in the heas internally???
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alan-g-w
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Possibly. Any mayo under the cap or oil in the coolant?
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harrisp
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quote:
Originally posted by alan-g-w
Possibly. Any mayo under the cap or oil in the coolant?
Nope, Im not even sure it was the headgasket in the first place.
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alan-g-w
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Have you checked for any air locks in the coolant system?
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DaveyLC
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quote:
Originally posted by harrisp
a steel ruler.
Just would be weird if the ruler was bent the same way as the head if it was warped.
A steel ruler will not be straight to those kind of tollerences.
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harrisp
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Could the head be warped and still be ok on compression and leak?
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harrisp
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any more help really stumped?
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oli_the_thread
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Registered: 26th May 09
Location: Leighton Buzzard
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for the sake of a couple of quid bang a new thermostat in!
This ALWAYS happens to me, fix one thing, and something completely unrelated breaks!
Could have even been an overheat from a dodgy 'stat that killed the previous HG
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harrisp
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It overheats without the thermostat in so thats ruled out isnt it?
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Richardhhha
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Registered: 29th Sep 07
Location: Croydon, Greater London
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air lock will make it boil up.
blocked rad aswell.
a steal rule is ok to check a block or head with really i.ve done it a few times and have never had any problems.
are the heaters in the car gettin hot and cold (normaly signifies its got a air lock)
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oli_the_thread
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well it will overheat without a stat, because it wont turn the fan on, leading to overheating?
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Gareth F
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Mine was boiling over all the time. Still does it but garages dont know what it is either. Vaux have self bleeding radiator systems ive been told. where is the bleed nipple on the radiator?
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harrisp
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quote:
Originally posted by oli_the_thread
well it will overheat without a stat, because it wont turn the fan on, leading to overheating?
My fan comes on without the stat in and Im pretty sure it had no control over the fan?
quote:
Originally posted by Richardhhha
air lock will make it boil up.
blocked rad aswell.
a steal rule is ok to check a block or head with really i.ve done it a few times and have never had any problems.
are the heaters in the car gettin hot and cold (normaly signifies its got a air lock)
The rad is probably only about a year old but I will check it in a bit.
Yes the heaters get hot.
I have got it up to temprature and ran it without the cap and turned the heaters on full, Im guessing thats right to bleed it?
quote:
Originally posted by Gareth F
Mine was boiling over all the time. Still does it but garages dont know what it is either. Vaux have self bleeding radiator systems ive been told. where is the bleed nipple on the radiator?
Mine boils over quite quickly, it is undriveable.
Im not bothered if the head does need skimming as TBH its not a huge job I just want to know 100% before I strip it down again.
[Edited on 27-08-2009 by harrisp]
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Gareth F
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Take it to get a "sniff test" they told me it could get a HG problem exhaust gas to coolant. a sniff test detects Co2 in the header tank etc. might help
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harrisp
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Right, Ive got it up to temprature and it sits at 95 ish but sometimes the water looks like its boiling but it only goes over 95 slightly, the fan comes on a lot.
It doesn't over heat but If I take the coolant cap off it boils over straight away.
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Richardhhha
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Registered: 29th Sep 07
Location: Croydon, Greater London
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when you took the head off did you check the water pump? sounds like it could possable be that aswell
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