Dex-Cool, what's the real story
#31
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#32
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Thought it was to prevent formation of AL2PO4.
Think my unscientific survey was that 1 out of roughly 5 auto-parts store stock G05 coolant. Tho that 1 store I found G05 only had the pre-mixed stuff.
And I'm not sure what they used to dilute the G05.
#33
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I stopped by the local carquest warehouse store. It wasn't at the normal suspects shelves, although I didn't try NAPA and should have. Carquest was on the way to somewhere else so an easy stop for me. NIce place, lots of more interesting stuff than Pep Boyz and Advanced have on their shelves.
#34
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I found this on another website (audifans.com) The author is the Chemistry Dept Chair for WVIT.
(Beating that dead horse a bit more...)
Chemistry lesson for the day: (He sez with an embarrassed grin on his
homely face) Aluminum blocks, etc., will tend to corrode, to some extent,
no matter what you do to your car. This corrosion will result in the
formation of Al+3 ions in the cooling system. (OK - no big deal - it's just
a normal long-term, slow, and not very sigificant, process which will
happen. Period.)
Al+3, in the presence of PO4-3 (phosphate), however, forms AlPO4, aluminum
phosphate, which has solubility properties similar to granite. If phosphate
is present in the cooling system, AlPO4 will be continually forming as the
Al block corrodes. Deposits of AlPO4 will form whereever the reaction takes
place. If left to go on long enough these deposits can block passages in
the radiator and limit the surface area through which heat can be
dissipated. The deposits are also less conductive than the radiator itself
which further reduces the effectiveness of the radiator by reducing the rate
of heat flow even through portions of the radiator which are still open
enough for collant to pass through. Eventually, the radiator will need to
be reoved and either replaced with a new one or cleaned and replaced after
cleaning. I don't have information on cleaning AlPO4 deposits from
radiators. It may work OK and then again...
An additional effect of the phosphate will be to reduce the concentration of
Al+3 ions in the coolant. The presence of Al+3 ions will tend to reduce the
rate of the corrosion. This is a benefit in that this will prolong the life
of aluminum parts. But if Al+3 ions are removed as AlPO4 this corrosion
rate will be accelerated somewhat. This will decrease (a bit) the life of
the aluminum block. This probably will not be a major consideration.
homely face) Aluminum blocks, etc., will tend to corrode, to some extent,
no matter what you do to your car. This corrosion will result in the
formation of Al+3 ions in the cooling system. (OK - no big deal - it's just
a normal long-term, slow, and not very sigificant, process which will
happen. Period.)
Al+3, in the presence of PO4-3 (phosphate), however, forms AlPO4, aluminum
phosphate, which has solubility properties similar to granite. If phosphate
is present in the cooling system, AlPO4 will be continually forming as the
Al block corrodes. Deposits of AlPO4 will form whereever the reaction takes
place. If left to go on long enough these deposits can block passages in
the radiator and limit the surface area through which heat can be
dissipated. The deposits are also less conductive than the radiator itself
which further reduces the effectiveness of the radiator by reducing the rate
of heat flow even through portions of the radiator which are still open
enough for collant to pass through. Eventually, the radiator will need to
be reoved and either replaced with a new one or cleaned and replaced after
cleaning. I don't have information on cleaning AlPO4 deposits from
radiators. It may work OK and then again...
An additional effect of the phosphate will be to reduce the concentration of
Al+3 ions in the coolant. The presence of Al+3 ions will tend to reduce the
rate of the corrosion. This is a benefit in that this will prolong the life
of aluminum parts. But if Al+3 ions are removed as AlPO4 this corrosion
rate will be accelerated somewhat. This will decrease (a bit) the life of
the aluminum block. This probably will not be a major consideration.
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#36
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FWIW, G-05 does seem to be kind of hard to find, at least around here. Don't know why... it's the only approved coolant for lots of Chrysler vehicles.
Anyway, finally found out that NAPA caries it (Zerex G-05). None of the other places around here (Advanced, etc.) carried it.
Needed it for the minivan last weekend. Now that I'm keeping it for that vehicle anyway, it'll probably go into the 928 next time I change coolant, probably within the next few weeks.
Anyway, finally found out that NAPA caries it (Zerex G-05). None of the other places around here (Advanced, etc.) carried it.
Needed it for the minivan last weekend. Now that I'm keeping it for that vehicle anyway, it'll probably go into the 928 next time I change coolant, probably within the next few weeks.
#37
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There is ONE coolant commercially available that is recommended and does not promote corosion of the aluminum in the heads. Zerex G-05 is what I and sveral other use exclusivly in the 928. You may have to call around as I know you cannot get it at Autozone or Advanced auto parts. I get mine here in Michigan from Murray's autp parts (now O'Riley so who knows if they will continue to carry it).
http://www.benzworld.org/forums/gene...ml#post2647584
I use the better stuff that comes in the white bottle :
http://www.benzworld.org/forums/gene...ml#post2646876
#38
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My GM minivan just blew a head gasket, this and blown intake gaskets are very common on GM products. The heads had corrosion and needed to be skimmed (82K miles). The intake gaskets were changed this past summer due to leaking. When I had the heads off you could see the Dexcool had jelled in the block and the rad cap was also gunked up. I don't trust the stuff.
There is a class action suit against GM and Dexcool, unfortunetly you had to file by last May.
Glenn
There is a class action suit against GM and Dexcool, unfortunetly you had to file by last May.
Glenn