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Discussion Starter #1
I thought I'd do the decent thing and having won all the things required to do the job I replace the belts, water pump etc. Driving home from work on Saturday the temperature gauge had a 'blip' shot to 120 then went back down, so didn't pay it too much attention (I'm new to this Alfa lark) which turned out to be the wrong thing to do.
On Saturday night the engine overheated with the loss of all coolant but managed to make it home. Sunday was another day in the garage & on stripping down found that the head gasket had failed on every cylinder. All the gasket material around the water jackets was almost totally disintegrated :eek:. Luckily the head seemed to be nice & flat. A new gasket set, bolts & thermostat were fitted & antifreeze added. The temperature is now nicely sitting at halfway & all's well :)
The old waterpump had almost no blades left on the impeller & there was little sign of antifreeze in the coolant when I replaced the belts. My theory is that with renewed water pressure & antifreeze this finally overcame the old gasket since antifreeze is the best leak seeker going :lol:. The lack of antifreeze was the main cause of the problem in the first place since there's a galvanic reaction between the aluminium & iron which antifreeze negates (or at least slows it down) & this is why apart from freezing you should check your antifreeze level & replace every so often.
I'm the evengelical antifreeze preacher :lol:
 

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Yes, same here... :thumbs:

I always fill up the system with a 50% mix (I think they don't recommend a higher concentration than that and do state "do not use undiluted") made with distilled water.

Top any small losses up with neat antifreeze, since the alcohol part of the antifreeze does evaporate out over time, making the concentration weaker with age.

Good coolant also theoretically keeps your thermostat working for longer :thumbs: though you will knacker it if you use tap water in the coolant, since scale will form on the delicate sliding part... clogging it up, even if it's not actually corroded.

Antifreeze also protects the Head Gasket. When mine burst (v6, 180,000 miles) I could see that coolant had penetrated into the gasket itself. Over time the metal mesh layers within the gasket had corroded and this had weakened the gasket. The resulting pressure one summer's day on a hot run... was too much for the remaining metal and the beast burst.

Always change the coolant... 2 years max, no matter what the pink stuff reckons... :) and don't drink it or get it anywhere near your mouth (it's actually a pretty lethal neuro-toxin) and obviously now you know this, don't tip it down the drain or into the ground... take it to the old engine oil recycling place at your local tip.


Ralf S.
 

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Discussion Starter #3
Good coolant also theoretically keeps your thermostat working for longer :thumbs: though you will knacker it if you use tap water in the coolant, since scale will form on the delicate sliding part... clogging it up, even if it's not actually corroded.

Ralf S.
Agreed Ralf, I've often wondered how much affect tap water from a hard water area will have on coolant performance. You should always use deionised water where possible. I admit that I didn't but water isn't particularly hard in my area & good antifreeze should prevent scaling also.
 

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Also if you overdo it on the antifreeze you may find that you boil up quicker. Ethylene glycol is more viscous (is more resistant to flow) than water & has a lower specific heat capacity (it can't take away as much heat) so you either have to increase the pump capacity or volume of the system to get same performance as a mixture of the two. Since this isn't practical we use a 50/50 mix. Another reason to use deionised water is that tap water may have chlorine in it which acts as a corrosive agent.
 
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