Which coolant should I use?

[98_SLE_98]

My ‘08 with 585k on the 5.3 is running dexcool still. I’ve yet to do anything to the engine since new. I replaced the rad hoses and heater hoses 4 years ago just because of age. My 98 is running green as that is what the previous owner had in it from many years ago and that gets done every couple of years.

 

[1998_K1500_Sub]

I have never heard of all this stuff about eating gaskets...

The coolant additive 2-EHA (2-ethylhexanoic acid), which was used in certain vendor's formulations, caused gasket leakage problems in a lot of vehicles:

"The inhibitor 2-EHA poses another
issue: It’s a plasticizer (softens plastic), so
it has been blamed for coolant passage
gasket leakage. Softening (and the re-
sulting distortion) was reported by Ford,
which encountered gasket leakage
problems when it tested a DexCool-
type formula on its V8 engines. Ford al-
so saw similar issues with other gasket
materials"

The above and more on 2-EHA can be found here: "Coolant Confusion: It's Not Easy Being Green ... or Yellow or Orange or ..."
https://www.motor.com//magazine/pdfs/082004_04.pdf

See also "Relearning the Alphabet: Making Sense of the Cooling System Scene"
https://www.motor.com/magazinepdfs/082010_08.pdf

EVERYONE ought to read these two. Yes that means you.

Other good information can be found by reading the patents issued to the various coolant manufacturers, e.g.,

5,071,582 COOLANT SYSTEM CLEANING
SOLUTIONS HAVING SILICATE OR
SILICONATE·BASED CORROSION
INHIBITORS
BASF CORPORATION

5,290,468 POLYCARBOXYLATE-CONTAINING
ANTIFREEZE/COOLANT ADDITIVE FOR
USE IN HARD WATER APPLICATIONS
BASF CORPORATION

5,342,537 RAPID COOLING SYSTEM CLEANING
FORMULATIONS
BASF CORPORATION

 

[L31MaxExpress]

But that's not the case, in an engine designed for Dexcool, baring other problems like an EGR cooler in a Ford Powerstroke, or a fitting that cracks on a 3800.



Yes, those new materials you listed (except iron). Green silicated wasn't the greatest with aluminum. Radiators used to be brass/copper, and engines had much less aluminum than they due now. Also there's more plastic. Even alloys have changed.... compacted iron? Magnesium with the aluminum (I know BMW did that).



Running straight water is a terrible idea, outside of maybe a race situation, where the next 500 laps is what matters. Old cars like Model Ts didn't run as long or hard as a modern engines.

There is a reason I run the Nissan blue. For past 2 decades Nissan engines are completely aluminum with iron liners. The blue protects aluminum much better and for a longer time period than Dexcool and it does not turn to mud with an unpressurized degass bottle. My 300K mile 2007 G35 still has a spotless coolant system with drain and fills every ~5 years. Same for the 2011 Pathfinder. When I changed the thermostat it looked new. Both still have OE coolant hoses as well.

 

[L31MaxExpress]

My ‘08 with 585k on the 5.3 is running dexcool still. I’ve yet to do anything to the engine since new. I replaced the rad hoses and heater hoses 4 years ago just because of age. My 98 is running green as that is what the previous owner had in it from many years ago and that gets done every couple of years.

Dexcool is not so much of an issue on that truck because it has a pressurized recovery tank. I am honestly surprised it made it more than 150K without needing a cam and lifters though. My uncle just had to put a new 5.3L in his 2010 Tahoe at 140K because of lifter failure. I tried to talk him into a cheaper L96 6.0L. Summit Racing had the last of them GM built for the vans for $1000 less than the DOD 5.3L.