aliveagain
Needs a life
Posts: 5033
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posted November 05, 2004 07:40 AM
black specks in the coolant
Anyone know where they're coming from?They almost look like black paint chips,real small and thin.I found them in the top of the radiator where the cap goes on.
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I wondered why the baseball kept getting bigger. Then it hit me.
  
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canadamaxxer
Pro
Posts: 1090
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posted November 05, 2004 08:14 AM
Could be scale buildups (mineral salts) that have broken free. I have also seen paint from the radiator neck break free on some cars (your rad is natural aluminium I assume so that won't be it). If you can pick a fleck out or two and determine how thick it is and/or how brittle it is, this might help.
When was the last time you changed your coolant? If your coolant is older it is possible that this concern is related to that. IMHO coolant should be changed every year....I use 50/50 green coolant and distilled water, mixed with water wetter. I DO NOT recommend Dexcool for any vehicle (my own personal experience as a mechanic).
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johnnycheese
Pro
Posts: 1008
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posted November 05, 2004 08:59 AM
Could be Headgasket material
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CrotchRocket
Moderator
Bracket Racing with Betsy
Posts: 8038
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posted November 05, 2004 10:10 AM
 Edited By: CrotchRocket on 5 Nov 2004 10:11
What happens with the 2000/2001 12s is the paint from the inside of the overflow tank comes off and floats around the coolant!!!
Hey Canadamaxxer that is the 3rd time I heard that GMs Dexcool is crap...What have you experienced???
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Jason Miller StreetBike Seminars
*****DragRacers do it better, because they dont cut Corners*****
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canadamaxxer
Pro
Posts: 1090
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posted November 05, 2004 10:42 AM
CR: In addition to the fact the Dexcool (polypropylene glycol) has been classified as a carcinogen, it has been the cause of $100,000's of dollars of failures in GM products that I have witnessed myself. Plastic gaskets (with silicone seals) seem to harden and break...and then leak coolant into the oil...which has resulted in engine failures. Dexcool seems to love to eat brass....tons and tons of block heaters have either leaked or blown out as a result of dexcool related corrosion...which results in the coolant blowing out of the engine (and sometimes directly onto the rear wheels) and potential overheating and engine failure. Water pumps are failing left and right. I suspect that the dissimilar metals (brass, cast iron, aluminium) in the presence of Dex Cool (which is classed as an Organic Acid) either creates an electrolytic reaction (basically creating a battery) which eats the weakest of areas or that the acidity is the cause of the failures....but I have no science to back this up, only what I have witnessed. In addition, if the coolant level gets low for whatever reason (a leak, improper filling), the Dex Cool seems to react to air under pressure and forms a brown chunky sludge which plugs the block, heater core and radiator. All of these symptoms are new since the introduction of Dex Cool. Sure, gaskets failed, radiators and heater cores leaked, and block heaters popped, but that is largely due to lack of service of Ethylene Glycol (the green stuff), simply because the coolant becomes quite acidic after the additives are depleted (1-2 years).
The newer engines seem to be better able to deal with the coolant, but we still see a pile of leaking head gaskets, intake manifolds and water pumps. Hell, I know guys who make 70-80 grand a year doing just coolant leak repairs...and I have largely done it myself, too. It is my understanding that Dex Cool is not GM specific.....Toyota uses it as well, and there may be others that I am not aware of. I have Dex cool in my truck, but I still have warranty, and as soon as the first leak happens, out the Dex Cool comes and in goes the green stuff with distilled water, which I have been told is good for up to 2 years. For my bikes...1 year only, but we have these tiny cooling systems...and with the big bores...they run substantially warmer.
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CrotchRocket
Moderator
Bracket Racing with Betsy
Posts: 8038
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posted November 05, 2004 11:06 AM
Thanks C...I now will flush the Dexcrap and go with Prestone!!!
The other 2 guys concur with the water pumps going bad and recommend flushing with the thermostat out for 20 minutes!!!
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Jason Miller StreetBike Seminars
*****DragRacers do it better, because they dont cut Corners*****
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canadamaxxer
Pro
Posts: 1090
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posted November 05, 2004 11:30 AM
If you have block drains in the engine in question, remove them and flush thoroughly with lots of water (you can do this with the engine running) and then allow the engine to thoroughly drain. Also remove the heater hoses and blow out the heater core (if you have access to compressed air) and I would go so far as to pop the radiator out and flush and drain it separately and also remove the overflow bottle and clean it so that it is like new (use a bottle brush to get into the hard-to-reach areas). This of course is model dependant..... you treat trucks a little differently than Sunfires (as an example)
There is also a caustic flush kit made by Prestone that can be used if you are noticing a reduction in you heater output...this is most noticable on Jimmy's/Blazers and S10 trucks. To do this flush properly it will take about 3-4 hours and will cost you a rad cap and a thermostat, but leaves the system squeeky clean and ready for new coolant.
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CrotchRocket
Moderator
Bracket Racing with Betsy
Posts: 8038
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posted November 05, 2004 01:04 PM
I have a 2003 Chevy Express 3500 Extended 15 pass with the 6.0 motor...Its going to be a bitch to do with everything cramped...
Thanks...
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Jason Miller StreetBike Seminars
*****DragRacers do it better, because they dont cut Corners*****
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BROOKLYNNYZX12
Zone Head
Posts: 520
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posted November 05, 2004 03:07 PM
Rick,I wouldn't go through the trouble of doing that,because your truck is newer it is compatible with the Dex Cool,or more compatible with it,wait till you experience a leak,or a failure,then do it...Toyota has been using this stuff for a long time...I think you should wait.
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Orient Express Top Street Bike Winner 8-4-07
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canadamaxxer
Pro
Posts: 1090
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posted November 05, 2004 03:38 PM
The problem is that waiting (assuming that Dex Cool is the source of the problems) will end up costing, at the least, a water pump. These newer engines (4.8, 5.3, 6.0) are far better for leaks than ever before, but we are seeing a surprising number of water pump failures. Is this caused by dex cool? I have no idea.........
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