I replaced the water pump on my car because coolant started to sip out the lower drain hole
I also took out the expansion tank to clean it since it was so diirty because of rust water and Dex Cool residue

Yesterday i filled the coolant system 2 times usin clean water, starting the engine in between and adding clean water in the radiator until the engine was up to norma temperatue and dlushed it out again

After the engine cooled down i added Valvoline VPS radioator flush using to clean the cooling system properly and started the engine at let it idle up to normal temperature and let the engine run for 20 minutes as the instructions on the radiator flush says

But when i drained th car after the radiator dlush the water was so dirty that i had to fill the car up with clean water, let the engine run up to normal temperature and then drained the water but still the water was to dirty for my liking

So today i have to add another bottle of Valvoline VPS radiator flush and clean water, let the engine idle for 20 minutes before drain and the go over and do the same process once more using clean water and hope that the water is clean enought that i can fill the coolant system with anti freexe and clean water

Is it the Dex Cool that GM use that is the reason that the cooling system on my car was so dirty?

When adding the new coolant i am using red Valavoline Max Life anti freeze

 

No, DexCool was not and is not the issue. We have had this discussion many times here. The problem was that back then the cooling system design was not the type that kept tiny amounts of air out of the system and combining air and DexCool is not good, plus at one time, coolant fluids were not always compatible with each other and they did not combine well with DexCool. Also, some people still believe that DexCool can go 100,000 miles without replacement.

GM still uses DexCool along with correct system designs very successfully in their vehicles.