gmcclurg

For the last 90,000 miles my Surburban has had Dexcool in it. Probably time to flush and replace. Can I use the regular Prestone type flush with Dexcool? I have also heard of some Dexcool problems, any thoughs on staying with it or switching to regular Prestone?
thanks
Gil

mayberg

I flushed the poopie out of my big block and put in Dex Cool. Mainly based on the low mileage and the long-term corrosion protection.

norvalwilhelm

I am a big fan of Dexcool. I started with a new aluminum rad and prestone. After a year I closely looked internally at my new rad and it was all coated/corroded inside. I flushed everything out and switched to Dexcool. The following year the rad looked brand new inside. I have used it for about 5 years now with the rad looking shiny and new inside.

LAvetteman

Rule of thumb: :thumbs: Stick with what originally came with your vehicle when it comes to oil(dino or synthetic) or coolant.

Follow the mixing instructions carefully. Some say Dexcool is critical.

tshort

The thing with Dexcool and the older green type coolants is that when they get mixed together they form a gel. And of course that gel can clog up passageways. So it really is best to stick with what you've got. But if you do change, make sure you flush system completely and very well with water.

My69

:iagree:

Paul L

You will not have a problem with the flush. But do not mix ethylene glycol with DexCool. The latter was developed for modern engines with aluminum components but it will work very well with older engines as well. There were early problems with brown sludge build-up but that seems to have been sorted out.

442olds

Mixing Green (glycol) and Red (dex) isn't good, if you do swtich from green to red be sure you have flushed every last drop of green goo out or your going to make a nasty black gooy mess inside the water passages and can in some cases clog up some of the passages. Had some first hand experience with this.

zwede

3 years ago I switched my 71 to dex-cool. I just drained the radiator and removed the drain plug in the block. Last week I decided to have it replaced as I'm sure there was still some green stuff in the system. Had a shop do a full coolant replacement. The stuff that came out looked brand new. Clear orange with no sludge or corrosion. I'm leaving it in for 5 years this time.

So my experience is that draining radiator and block is good enough, no need for a flush. Of course I may just have gotten lucky.

Fang S-289

My experience is that Dex Cool is a long lasting coolent that provides excellent protection....*IF* no air is allowed to enter the system. If air finds it's way into the cooling system the Dex Cool becomes a mass of sludge that is very hard to remove. I had great service from the factory installed Dex Cool in my C-5. But I decided to err on the safe side now that it's aging and I flushed and installed ethylene glycol.

Paul L

You are bang on! Some of the earlier problems re sludging related to defective rad caps on GM V6 engines, particularly with Buicks. The caps would not seal properly owing to burrs in the rad neck and air got in. The result looked like chocolate pudding. Saw many of those when I worked for GM in 2002-03.