Head Gasket Question

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Mon 19 Jan 2004 13:48
Head Gasket Question - pullgees
If a head gasket has failed between a water channel and a combustion cylinder there will be a build up of pressure in the cooling system but water will not get into the oil. Is that correct?
If a head gasket has failed between an oil channel and a water channel there will be NO build up of pressure in the cooling system but water will get into the oil. Is that correct?
Thank you.
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Mon 19 Jan 2004 13:56
Head Gasket Question - A Dent{P}
That is how I understand it. I have had the former, the combustion pressure rapidly emptied the water system via the expansion tank and the pulse rate left no doubt where it came from. A cracked head can give the same symptoms.
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Tue 20 Jan 2004 00:06
Head Gasket Question - NormanB
It aint necessarily so!!

Gasket failure between water channel and combustion chamber

All things being equal when the engine is running the pressure in the cylinder varies from 'high' (when the coolant system will over pressure) to 'negative' when it is possible for 'water' to enter the cylinder which would immediately turn to vapour because of the temperature and appear as steam in the exhaust. However when the engine is shut down and as it cools there is a possibility that water could pass into the cylinder and thence into the sump and lubricating oil.

Gasket Failure between Oil and Water Channel.

Not easy this one ( but result is same) because it depends if the oilway is pressure or drain. If pressure then oil pressure is usually 3 bar, Coolant system say about 1.5 bar so oil will end up in the expansion tank. If the oilway is drain (returning to sump) then the coolant will be at a higher pressure and travel into the sump via this route.

Not sure why you ask the question but it is simple to test gor head gasket failure if you have the kit - a test for hydrocarbons in the expansion tank is one go/no go test, the other is a water pressure squeeze on the expansion tank.
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