Author Topic: Mixing different extended life coolants  (Read 1540 times)

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Offline dieselnewbie

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Mixing different extended life coolants
« on: March 29, 2019, 03:45:24 PM »
Last fall we trashed a CAT 3126E that was replaced with a 3126B by an independent shop.  The 3126E cooling system had CAT EC-1 in it.  When the 3126E was removed, it is presumed (by me) that all EC-1 coolant that would gravity drain out was drained.  However, that left EC-1 in hoses that went to the cabin heater core, the domestic hot water heater that has a coolant core in it and anything else that wouldn't easily drain.  The system for the 3126B was filled with Prestone Command Heavy Duty Nitrite Free extended life pre-diluted.  See attachment.  My wild guess is that the ratio of Prestone to CAT EC-1 exceeds 100 to 1 at this point. 
I think I have a very small coolant leak to deal with.  Do I have a bigger problem with the mixing of the 2 different coolants? 
I have a small quantity of CAT EC-1.  Can use it safely/wisely to add to the mix I already have?

My apology if this has been covered before and I didn't find.
2002 DSDP CAT 3126B Freightliner XC/ '99 4runner manual trans

Offline Brett Wolfe

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Re: Mixing different extended life coolants
« Reply #1 on: March 29, 2019, 07:11:17 PM »
We can speculate (my suspect is that it is not critical).

BUT, by far the better advice is to pull a coolant sample and have it analyzed by one of the labs that specialize analyzing fluids.  Let them know what two coolants are in there and what ratio you suspect.