Bleeding Cooling System
06-07-2011, 07:44 AM
#11
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The OEM LIM gaskets are the problem, not the DEX. I've seen more then my fair share of LIM gaskets, and never seen any to fail due to DEX.
06-07-2011, 10:21 AM
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You can open it when the engine is running. Be careful as it could spray you. Me however, I never use that bleeder screw. I fill the system threw the thermostat hole, then install the thermostat and top off threw the radiator cap. When I have it full I put the cap on and squeeze the top radiator hose. If there is any air under the thermostat it will force the thermostat open and push fluid threw.
06-07-2011, 10:25 AM
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By the way, here is some information I had posted up about DEX and gaskets. Hope you find this article useful. https://www.gmforum.com/specifications-general-information-132/lim-gaskets-myth-fact-288248/
06-07-2011, 06:37 PM
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There have been a number of people that spread hysteria without any data to back it up. I did this experiment on my own engine, as well as years of experience dealing with the 3800 engine. I have seen several engines with failed LIM gaskets that are running green. But have never seen a failed LIM gasket that is aluminum framed. No mater what coolant is used. That suggests to me, the coolant isn't the problem, the design of the gasket is.
06-07-2011, 08:47 PM
#17
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i dont have any experience with the gasket failure issue but i have with dexcool turning brown and sludgy without air being introduced or any of the other common theories as i owned the car and my moms from almost new and inless than 2yrs and 50k they both were permanently stained, i always now use prestone extended life which doesnt make a mess and works well for a long time. and my 3400 montes(at 170k), my moms imp(75k), and my bonnie(155k) are known for gasket failures and i havent had one.
06-08-2011, 07:15 AM
#19
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No it won't eat gaskets. When you've seen as many as say Dan and I have, you start to get a clearer picture and ask more questions. The plastic gaskets have relief notches and it'* those areas that collapse. Then the seal is compromised. The issues are more heat related than coolant related. Dex will sludge/turn back to OAT with air and it does turn brown when mixed with the old green coolant.
OP: it sounds like you may want to perform another flush and ensure you flush the motor well. You may have gotten some mixing.
OP: it sounds like you may want to perform another flush and ensure you flush the motor well. You may have gotten some mixing.
06-08-2011, 11:29 AM
#20
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they came with dexcool and i flushed them out a couple times and switched to prestone as soon as they started turning brown. the bonnie never turned brown i just switched because its just easier to have prestone EL that goes in everything i own. and last time i checked it was the same or less than the prestone dexcool.
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