At what water temp would damage occur to a engine

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CITMAN
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Joined: 02 Aug 2002, 00:22
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At what water temp would damage occur to a engine

Post by CITMAN »

I had posted another problem earlier regarding my coolant temp readings under load. But at what temp would an engine become damaged especially an all alloy engine like my zx 1.4i. Might be a stupid question. And if the engine was too hot what symtoms would i have in terms of running chracteristics that might tell me if somethings was wrong apart from the gauge readings which I dont trust anyway unless that is its going stupidly high.
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AndersDK
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Post by AndersDK »

Citman -
Wheter the engine block (crankcase) is alloy or cast iron does not mean any big differences to overtemp. It's the cylinderhead that's sensitive to such problems.
Alloy cylinder heads warps (flexes) when opposed to (too) high (& uneven) engine temperatures - and it will NOT "flex back" when cooled down.
This means the cylinder head gasket partly is no longer torqued down - and the gasket "blows" - with the wellknown result of engine oil, coolant & combustion pressure suddenly allowed to get into places not foreseen.
This happens contrary to the cylinder head bolts correctly torqued down. It won't help trying further tensioning the cylinder head bolts - the process is purely thermo-metallurgic.
The consequence is a major engine repair - meaning cylinder head off & regrinding to a square & even gasket surface.
In severe cases the cylinder head may warp to such an extent - that the cam axle bores (bearing housings) no longer are squarely in-line. A new cylinder head is then the most economical solution.
Having done such a job lately on a n/a BX 19diesel - I was rather shocked to see that several of the small coolant pass-thru holes in the headgasket was CLOGGED by dirt & calcium.
In this instance the cylinder head had partly been opposed to overtemp (at the clogged coolant holes) which made the head warp - and the cylinder head gasket leaked engine oil badly - some 2L's pr week - quite messy on parking lots.
No incidents without learning something.
I find it's quite important to run a coolant system cleaning cure - to prevent the gasket clogging up - and ensuring a good flow in the cooling system.
This should be done at sensible intervals - like every 60Kmiles or 5 y's.
A weak acid mixture should be used - like standard kitchen vinegar.
50% vinegar to 50% tapwater - run it for a couple of weeks.
The vinegar has a couple of major advantages : it's cheap & readly available everywhere - & it's harmless.
The major DIS-advantage : the sharp & sour smell - may however also be advantageous - any leaks in your cooling system will instantly & mercyless alarm your nose [:D][:D]
Finally the cooling system is flushed and drained again - then refill with adequate coolant mixture - using de-calced water.
A cheap & readily source of de-calced water may be the ice build-ups from your fridge [8D]
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