Blake, are you saying that the green stuff is safe for aluminum? I wouldn't
be surprised since so many parts are Al these days. The reason I ended up
with the orange is that I knew for sure that it was safe on Al, and I
couldn't get any solid answers locally on the green.
The only non Al left in my system is the heater core, a couple of brass
fittings, and two steel hardlines from block to radiator.
James Nazarian
71 B tourer
71 BGT V8
85 Dodge Ram
----- Original Message -----
From: Bullwinkle <yd3@nvc.net>
To: james <jhn3@uakron.edu>
Cc: <mgs@autox.team.net>
Sent: 28 February, 2003 2:46 AM
Subject: Re: Coolant
> Jim:
>
> <<<snip>>>
> They still recommend the same standards of mixture. Do they use a
> longer lasting corrosion inhibitor or what?
> <<<Snip>>>
> Maybe, but you've also changed the cooling system from dissimilar
> materials (cast blocks with aluminum heads) to one of just one material,
> aluminum, instead of the all cast iron of 30 years ago.
>
> The main reason for the 50/50 mix TODAY is to control the boiling point
> of the coolant. It has nothing to do with the quantity of additives.
> Modern cars must run hotter to control emissions. Anti-freeze raises
> the boiling point. Older cars using water and running at a coolant
> temperture of 175d F have a margin of 37d F before boiling. Many modern
> engines use a 190d F or 195d F thermostats. With straight water and a
> 15 lb. radiator cap the boiling point is 230d F. (Notice the 220d F
> STABILIZED temp in one of the charts I referenced.) Antifreeze
> increases that safety margin more. So that's the main reason why they
> specify the 50/50 mixture. The hotter temps are also the reason for the
> pressurized systems. Notice that car makers keep raising the pressures
> in the systems rather than increasing the antifreeze ratio to control
> boiling.
>
> In regards to the 5 year life, I have read that the additives for
> corrosion have evolved over the years taking into account the more
> extensive use of aluminum in engines.
>
> Consider the situation 35 or so years ago. Except for the exotics, AMC's
> aluminum block 6, or very early Ford flat head V8s, most engines were
> all cast iron. In other words there were no dissimilar metals in the
> cooling system. So the additives only need to protect against rust.
> (BTW, Ford discontinued those early aluminum heads after a few years due
> to corrosion problems.)
>
> Then came the modern aluminum heads and water pumps. This is probably
> the worst condition because you have about 1/2 of each type of metal in
> the cooling system. Thus galvanic and electrolysis corrosion could be
> very active besides rust of the iron components. So the additives get
> used up faster trying to protect the system.
>
> With your all aluminum system there are again no (or few) dissimilar
> materials. The only additives needed are to protect the aluminum and
> electrolysis is at a minimum. Therefore the protective additives get
> used up more slowly.
>
> Cooling systems were designed for the coolant available at the time they
> were designed. Anybody remember when alcohol used to be used for
> anti-freeze? England doesn't have the real cold that we have in the
> northern plains. Cooling systems for the T types and MGA were suitable
> for England's milder climate and WATER coolant or low antifreeze mixes.
>
> Glycol was very expensive in the 50's so minimal amounts were used IF
> NEEDED. The 1956 Montgomery Wards catalog lists THEIR BRAND at $2.19 a
> gallon plus shipping while men's denim's (blue jeans) are as low as
> $1.66. And, they probably had the cheapest price for antifreeze
> available. The TD shop manual says: "If ... anti-freeze mixture is in
> use, the water should be drained into a suitable clean container and
> kept for future use. ... Avoid over-filling when anti-freeze is in use,
> to prevent unnecessary loss on expansion." Nothing is mentioned about
> quantity of use. The MGA twin cam shop manual lists anti-freeze needed
> in three steps down to 35 degrees of frost. That's minus 3d F and a tad
> over a 25% anti-freeze mixture. Again cost was being considered.
>
> Today, the radiator and cooling system is designed for a 50/50 mix and
> the radiator, pump, and coolant flow are sized appropriately.
>
> Blake
>
> P.S. Pure anti-freeze has a specific heat of 0.675 compared to waters
> 1.008 at 212d F.
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