Dex-Cool, what's the real story
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#18
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Here you go... the last post has links to two previous threads.
https://rennlist.com/forums/928-foru...t-coolant.html
I think using distilled water is important, there's enough chemicals in coolant without adding more.
Which leads back to the OP's problem with the block drain: It's going to be hard to flush the block effectively without getting it out.
https://rennlist.com/forums/928-foru...t-coolant.html
I think using distilled water is important, there's enough chemicals in coolant without adding more.
Which leads back to the OP's problem with the block drain: It's going to be hard to flush the block effectively without getting it out.
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In this case my bet is that the last time no paste and/or no new crush ring was used and/or the plug is way too tight.
I have had success with removing crudy plugs with my special set of 'rounded-off' bolt sockets the likes of which you can get on the web etc.
However, if the threads in the block drain have been stripped then removing the old plug could lead to a bigger problem. Unfortunately I don't know a way to tell without opening the box.
If the block drain boogy man is too frightening, then I'd do one or two flushes with distilled water to at least dilute the stuff that's left in the side of the block that cannot be drained.
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At one of the financial institutions I formerly worked for, we had a repo that came with that stuff as a factory fill. During the course of inspection when we got it back, I took off the radiator cap for a look. The passageways were largely blocked with a sludgelike substance, not the normal deposits you see. Dexcool will never see use in my 928. YMMV.
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#22
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#23
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The G05 stuff is not too dificult to find, so there's not much reason to worry yourself by using Prestone in your 928.
I've had varying results using Prestone in other cars. For instance, the 2004 4-Runner is supposed to use the Dex-Cool, according to the G05 bottle. Aluminum heads on a FE block. I was planning to use the G05 but stopped. I may just buy the Toyota stuff and sleep better. In my now-gone Explorer, I had a head gasket leak coolant externally after a year of Dex-Cool. Replaced the gaskets, no problems. No evidence of gum precipitate in that system, but it was low-dosed (25%) with Water Wetter.
The block drain bolts seem to like to get stuck for some reason. My solution has been to use a 6-pt socket on a 1/2" drive, long handle, and pull. Wrestling with 3/8" drive or 12-pt sockets is risky to the bolt and/or your hands. Similar to what Dave recommends, I added a little teflon past to the threads with new washers. Then you just need to use enought torque on the bolt to make sure it doesn't fall out, since the washer isn't doing the sealing any more. Do Not use a lockwasher, since this will damage the sealing surface on the block and doom future users who might depend on the washer doing the sealing. The teflon thread sealing paste is in the plumbing section at Home Depot. You can also use Hylomar or Yamabond/Hondabond paste. New bolts are always a good idea, especially if you've (or the PO...) stretched them, or torqued heavily on them to get them out.
I've had varying results using Prestone in other cars. For instance, the 2004 4-Runner is supposed to use the Dex-Cool, according to the G05 bottle. Aluminum heads on a FE block. I was planning to use the G05 but stopped. I may just buy the Toyota stuff and sleep better. In my now-gone Explorer, I had a head gasket leak coolant externally after a year of Dex-Cool. Replaced the gaskets, no problems. No evidence of gum precipitate in that system, but it was low-dosed (25%) with Water Wetter.
The block drain bolts seem to like to get stuck for some reason. My solution has been to use a 6-pt socket on a 1/2" drive, long handle, and pull. Wrestling with 3/8" drive or 12-pt sockets is risky to the bolt and/or your hands. Similar to what Dave recommends, I added a little teflon past to the threads with new washers. Then you just need to use enought torque on the bolt to make sure it doesn't fall out, since the washer isn't doing the sealing any more. Do Not use a lockwasher, since this will damage the sealing surface on the block and doom future users who might depend on the washer doing the sealing. The teflon thread sealing paste is in the plumbing section at Home Depot. You can also use Hylomar or Yamabond/Hondabond paste. New bolts are always a good idea, especially if you've (or the PO...) stretched them, or torqued heavily on them to get them out.
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I've had varying results using Prestone in other cars. For instance, the 2004 4-Runner is supposed to use the Dex-Cool, according to the G05 bottle. Aluminum heads on a FE block. I was planning to use the G05 but stopped. I may just buy the Toyota stuff and sleep better. In my now-gone Explorer, I had a head gasket leak coolant externally after a year of Dex-Cool.
#25
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+1 for the Zerex-G05 - I use it on MY 81 and 84.
A local pro wrench tells me that Zerex-G05 is better for the older cars (late 70's to late 80's/early 90's).
When I mentioned Dexcool he said that's for mid 90's on applications.
Just my $0.02
Cheers,
A local pro wrench tells me that Zerex-G05 is better for the older cars (late 70's to late 80's/early 90's).
When I mentioned Dexcool he said that's for mid 90's on applications.
Just my $0.02
Cheers,
#26
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Just use Zerex-G05 and distilled water ONLY and you won't have a problem. I've run it in all my cars for years. Around here they sell it at Autozone, NAPA and Advance Auto Parts.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C 475hp/460lb.ft
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#28
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Well... folks that worry about no phosphates not protecting against damage caused by water pump cavitation?
Or folks that don't know whether or not they're using distilled water?
OH.... for $hi+$ and grins (not for you BB):
Or folks that don't know whether or not they're using distilled water?
OH.... for $hi+$ and grins (not for you BB):
Last edited by worf928; 04-21-2009 at 03:10 PM.
#29
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I was correct. Here is the FAQ from Prestone's website:
Q. Does Prestone® Antifreeze/Coolant contain phosphates?
A. Some European automobile manufacturers request that a phosphate-free antifreeze be used in their vehicles. This issue is related to the extremely high mineral content of the water in Europe. If you were to mix an antifreeze that contained phosphates with the type of water they have in Europe, it may produce deposits that can settle in the cooling system and promote corrosion. However, in North America we do not have this type of water problem. Typical North American coolants have contained phosphates (which is part of the corrosion inhibitor package) for many years. Therefore, the question of phosphates is a non-issue here in North America. Prestone® Antifreeze/Coolant is completely safe for use in both foreign and domestic vehicles. For those consumers who would feel more comfortable using a phosphate-free antifreeze, our Prestone® Extended Life 5/150 Antifreeze/Coolant is phosphate, silicate, and borate free. This coolant uses a special chemistry and technology that extends the life of the corrosion inhibitor package so that it lasts for five years or 150,000 miles (whichever comes first), and is safe for all cars and light trucks (old or new). Prestone® Extended Life 5/150 Antifreeze/Coolant has been approved by General Motors under their DEX-COOL® specifications and is compatible with other DEX-COOL® approved coolants.
Q. Does Prestone® Antifreeze/Coolant contain phosphates?
A. Some European automobile manufacturers request that a phosphate-free antifreeze be used in their vehicles. This issue is related to the extremely high mineral content of the water in Europe. If you were to mix an antifreeze that contained phosphates with the type of water they have in Europe, it may produce deposits that can settle in the cooling system and promote corrosion. However, in North America we do not have this type of water problem. Typical North American coolants have contained phosphates (which is part of the corrosion inhibitor package) for many years. Therefore, the question of phosphates is a non-issue here in North America. Prestone® Antifreeze/Coolant is completely safe for use in both foreign and domestic vehicles. For those consumers who would feel more comfortable using a phosphate-free antifreeze, our Prestone® Extended Life 5/150 Antifreeze/Coolant is phosphate, silicate, and borate free. This coolant uses a special chemistry and technology that extends the life of the corrosion inhibitor package so that it lasts for five years or 150,000 miles (whichever comes first), and is safe for all cars and light trucks (old or new). Prestone® Extended Life 5/150 Antifreeze/Coolant has been approved by General Motors under their DEX-COOL® specifications and is compatible with other DEX-COOL® approved coolants.
Please stop giving me heart attacks. I have a hard enough time keeping straight what I am supposed to be doing to take good care of my 928 without having to panic about something I thought I had figured out before.