Duramax- Dexcool Change Interval

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How often should I be changing the antifreeze in a Duramax with high engine hours. It does a lot of low speed heavy towing on dirt/gravel roads and idling. The truck in question is a 2016 LML with a little over 55k miles and about 4,000 engine hours. The manual lists 5 years/150k miles in both the regular and severe service sections.

If you look up the Ford Powerstroke recommendation for the 6.7L, they suggest 45k miles or 1,800 engine hours when operating under "special operating conditions" and checking the coolant additives every 15k miles/600 hours.

https://www.powerstrokediesel.com/docs/Coolant_Information.pdf
 
I've used 5 years on my 2008 6.0 Chev gas engine which means two changes since new with Dexcool. 200,000 miles and all cooling parts are original, including the rad, water pump, heater core and all hoses.
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If you want to step up from the 5 year regime may I suggest draining the rad everything 2-1/2 years and adding 50/50 Dexcool and water, then do a full change every 5 years. What ever eases your concern.
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Originally Posted by WyrTwister
Buying 50/50 mix is just stupid and lazy ! :-(

Buy 100% .


I said add 50/50 Dexcool and water, meaning 50% concentrated Dexcool and 50% water. I was not referring to a premixed 50/50 solution. But otherwise I agree with your assessment.

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If it is anything like the PSD, you have to periodically check the coolant and see if there are still active additives in it. The coolant additive "revitalizer" can only be done twice before having to flush/refill with new coolant. Not sure how it works for GM diesels, but suspect it cannot be that much different.
 
I would stick to the manufacturer's recommended maintenance interval, GM has been making Duramax diesel's for over a decade and they're not known for having cooling system issues. Many gas and diesel GM truck owners push Dexcool far beyond 5yrs/150k with no issues, so if you're within or at the factory service interval you're safe and there's no need to make yourself safer.
 
Originally Posted by Snagglefoot
If you want to step up from the 5 year regime may I suggest draining the rad everything 2-1/2 years and adding 50/50 Dexcool and water, then do a full change every 5 years. What ever eases your concern.
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I do partial drains and make my mix with 50/50(distilled) refilling every five years and never had a problem. Never seen the need to do it more often unless you are using the green coolant.
 
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