Corrosion protection vs coolant/antifreeze %.

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Hi guys,

Just changed a leaking noisy water pump in my Vauxhall C20XE engined Caterham and need to refill with coolant. Caterham actual suggests only 30% antifreeze vs the standard 50% (presumably to aid in cooling) but I'm wondering what effect that has on inhibiting corrosion?

I've read various opinions including that at little as 10% AF is all you need to prevent corrosion vs straight water. My thinking is that going with the recommended 30% is fine for the first couple of years but could shorten the coolants life.
BTW I picked up some Peak 5 year AF that I'm planning on using.

Thoughts?
 
Simple shorten the antifreeze maintenance interval in half and worry less.

Another option is to use a coolant additive to give you the corrosion protection you might want.

Just know your ratio and how it relates to freezing temp and your winters/storage....

Peak 5 year at 50% is now 3 year at 30%...crude math but keep an eye on the look off your coolant.
 
Correct. Using less antifreeze in the solution is valid idea, but you have to change it more often. It is still best to use the 50/50 ratio if possible. My Lotus Elan never needed less than 50/50 here in southern California, you really need 30% for a Caterham 7 in England? I would keep the 50/50 unless I was certain I had a problem, and then a better radiator would be the best way to go. You never want a marginal radiator, you ALWAYS want overkill!
 
Marginally off topic, but I always use distilled water plus Redline's Waterwetter in my oldies (obviously not the Beetle!) 20-30% antifreeze.
 
30% is/was the standard in Oz forever, nowhere on the continent could you find a place that "needs" 50:50.

You'll be fine anywhere between 33 and 50%
 
Are you sure it says 30% antifreeze and not 30% water. And since your in Canada....that 70% water...may be a problem.
 
Since I don't have any cooling issues (the rad's more than big enough) I may as well go with the standard 50% concentration to maximize coolant life.

I don't know if it's already been discussed in this forum but do the OEM coolants such as the Asian types that claim 10 years, 300K kms actual last longer than those extended life coolants that only claim 5 years?
The European OEM AF/coolants don't claim a maximum life (that I've seen) but a Porsche mechanic friend says 8 years.
 
I changed coolant in my S2000 for the fist time few months ago, after 11 year and 55k miles the coolant condition looked excellent, looking into radiator I didn't see anything other than shiny metal without any sign of corrosion.

From what I saw I think it could be in the car for another 4-5 years without problem, it was very clearly Honda factory filled coolant can be in service for 15 years or longer.
 
I would stay with 50/50 coolant and distilled or deionized water. No cooling system additives.
The number of heating and cooling cycles is what depletes the coolants additives not just time. Sitting in the jug does not deplete it.
 
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You guys are probably right, mileage is probably more importance than time. But the owner manual recommends 10 years or 100k(may be 120k) miles, and the cost of a gallon Peak Global Lifetime is only $15 plus 2 gallons distilled water at 99c/ea for a total of $20 is so little to not do it. But as I said, after draining the coolant into a container and seeing how good it was I regretted changing it. The other reason was it was last January and we had several days with nice weather in the 80's, I was bored so I tried to find something to do.
 
Originally Posted By: HTSS_TR
You guys are probably right, mileage is probably more importance than time. But the owner manual recommends 10 years or 100k(may be 120k) miles, and the cost of a gallon Peak Global Lifetime is only $15 plus 2 gallons distilled water at 99c/ea for a total of $20 is so little to not do it. But as I said, after draining the coolant into a container and seeing how good it was I regretted changing it. The other reason was it was last January and we had several days with nice weather in the 80's, I was bored so I tried to find something to do.


You did good, do not worry.

If you wait until the antifreeze looks bad then a flush may be in order because all the internals could be coated in mess/slime.
 
Lots of good suggestions here, CATERHAM. I'd not worry about the 30% coolant, unless you happen to decide to leave it outside all winter and get hit with a dirty one.
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What's the capacity on it? If you're concerned about corrosion protection and the capacity isn't too big, more frequent drains and refills couldn't hurt.
 
Originally Posted By: Garak
Lots of good suggestions here, CATERHAM. If you're concerned about corrosion protection and the capacity isn't too big, more frequent drains and refills couldn't hurt.

Hi Garak,

Yes corrosion protection is my only concern.
Unlike an oil change, a coolant change is not so straight forward particularly in this application where properly bleeding the system can be difficult to do. So not changing the coolant any more frequently than necessary is desirable.

With that in mind I'm planning on returning the 5 year PEAK AF I bought and pick-up some 10 year Asian AF and going with what appears to be the optimum 50/50 mix.
 
I have ran anywhere between 30%-50% coolant with zero problems. This includes parked in single digit temps for 2 days w 30% supertech all makes all models. Truck ran fine. If I lived in Canada, I would probably go closer to 50/50. In socal, 30% coolant is good with drain and refill every 2 years.
 
Bleeding, that's always fun. Is there any concern about which chemistry is most optimal for its cooling system? If some 10 year Asian stuff will work as advertised, that's fantastic, then!
 
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