My coolant level had dropped due to antifreeze leaking out of my loose block heater. I tightened up the block heater (it was really loose) and needed to add some coolant to the resevoir. I noticed my coolant was an orange'ish color. I picked up some Zerex Extreme Extended Life coolant with the orange cap which said it was compatible with all extended life coolants. I added about 0.7 gallons to the resevior and then noticed that the container said it was Dexcool compatible. I didn't think this sounded good because Chrysler doesn't use Dexcool. I checked my owners manual and it says to only use a HOAT (hybrid organic acid technology) coolant. Turns out the Zerex I used is an OAT (organic acid technology). I asked my Dodge diesel technician if this was a problem (mixing the two types), and he said that if it had the orange cap it was fine. I called Cummins customer service and talked with a gentleman there and he said the same thing.

What concerns me is this from http://www.penray.com/bulletins/dexcool.htm:
How can a customer tell if he has DEXCOOL?
If the customer owns a GM car and has orange coolant, then its DEXCOOL! In GM trucks the coolant is "orange- red", indicating that it contains nitrite. Orange coolant in Daimler-Chrysler® vehicles is NOT Dexcool. (Daimler Chrysler owners with orange color factory coolant should consult their owners' handbooks).

OK, so it's the same color as the Chrysler antifreeze, but it's not the same thing. Why do they use the same color then!

But then it also says:
Can DEXCOOL organic acid antifreeze be mixed with ethylene glycol antifreeze?
It is ethylene glycol based antifreeze! The concern with mixing comes from the fact that there are very different chemical inhibitor packages in use. Most leading technologies will work very well when used as intended, typically at 50% in good quality water. If the coolants become mixed with DEXCOOL, however, one study showed a possible aluminum corrosion problem in certain situations. The other question is a concern for dilution of the protection packages. At what mix is the there too little of either inhibitor to protect the engine? As a precaution, both GM and Caterpillar instruct that contaminated systems must be maintained as if they contained only conventional coolant.


So my question is do I need to flush and re-fill my entire coolant system? I have 22,000 mls on the engine. Or can I go the full life of the coolant as recommended in the owners manual? Or do I need to treat it like a non-extended life coolant? Any thoughts or suggestions are appreciated.

 

Go to Cummins and get their pre mix. Also here's some reading you can do.


http://www.findarticles.com/p/articl...08/ai_n9453107

 

Thanks for the response. Great article. Wish I would've read it before I did what I did. Do you think I should drain my system and re-fill? If I added 0.7 gal to the 7 gal system this would be 10%. Is that enough to contaminate the coolant?

 

Flush twice and refill----did that by accident on my motorcycle and after only 3 months on a over reving problem (dropped a valve) sent the engine back to the builder (Scott Shafiroff Racing)who called and informed me that they noticed some corosion during tear down and asked me if I had mixed coolant types!