Coolant Flush After Seeing Gunk?

[NewLeSabreOwner]

I did the quick fix of the replacing the temperature sensor, I did not drain the whole system, just made sure to be ready to replace it seconds after taking the old one out and only lost maybe 2 to three cups max of coolant. I however doing that did want to make sure I topped it off and when I took off the radiator cap, saw a decent amount of orange brown sludge / gunk. Now I am thinking it would be best to do a coolant flush, or could I possibly by doing that make things worse off than just letting it stay? If I do, I have been reading a little, should I do the multi flush idea with distilled water for a couple until it's clear and then coolant or just change the coolant and be done with it or even just use the flush cleaner? And lastly, does anyone have a recommendation on what coolant is the best, I know the car did have its radiator replaced before I bought it and I do not think it's using the DEX anymore.

Thanks.

 

[2000ltd]

Imo Use zerex radiator service flush according to directions then I would flush 3x with distilled h2o and then fill with 1 1/2 gallons of concentrated dexcool.

 

[kmart2026]

Sounds Like the Dexcool sludge. Depending on where you are and the weather, its pretty easy to do yourself. The first Lesabre I had was bad with it and I had a few days where I had time in the summer to do it well. Started with draining from the bottom hose. Ran the garden hose through the radiator to loosen some stuff up. Filled it with distilled and a cleaner. Drove around town twice drained again. Filled it with distilled and cleaner, repeated this until it was as clear as I could get it. Filled up with half concentrated DEXCOOL and Distilled water. One thing that I did Learn recently while doing my water pump was you can add coolant in through the tensioner. It helps to speed up the Burping process.