orca1946

I just printed this out to do this summer.

Bill Suttie

Would you be good enough to enlighten us all as to what chemical reaction occurs to cause Dexcool to gum up.

orca1946

Why not flush with hose water?

Bill Suttie

Data talks, BS walks

Brim

Not all of the coolant can be drained, so you are left with ~4.5 qts of water in the system. That water will remain in the system until your next flush and since tap water contains minerals, which can be corrosive, distilled water is preferred.

Marc V.

Do a google search.

I work at a dealership for the last 21 years and speak from experience.

Bill Suttie

Marc V Please check private messages. Bill S.

Bill Dearborn

I use drinkable tap water. Distilled water is an overkill and a hose makes things a lot easier. Been draining and refilling Dex in GM cars since 2002 with no issues using original Texaco Dex Cool or the new Prestone version which is the same thing now that Texaco doesn't own it any more. One thing. If you want a 50/50 mix after you are done do not use a 50/50 pre-mix. Since you can't drain everything out of the block and if you flush the coolant several times with fresh water until the drained coolant runs clear you will get less than a 50/50 mixture in the system if you use a mix to refill it. There are ~ 3 qts of water left in a completely flushed block so on a 12 qt system it is really easy to just add 6 qts of Dex and top off with water. You will have a 50/50 mix. If you use the premix stuff you can't get to a 50/50 mix because you only have 9 qts remaining that can be added. So you end up with a 38/62 mix of antifreeze to water instead. 50/50 premix is only used for topping off if you have some sort of coolant loss.

Bill

Cruncher

Tap water is used at Bowling Green. From what I've read, Dex-Cool will neutralize the minerals from tap water (per GM from what I remember & also a sticky in the C-5/C-6 section). For me, although it's much more expenseive, I use Prestone 50/50 pre-mixed, every three years, plus a bottle of Red Line Water Wetter for additional corrsion protection. I go to a fomer GM dealer that uses Wynn machines + Wynn chemicals.

Cruncher

Using a machine like Wynn or BG will flush all of the old coolant from your cooling system. Doing a manual drain & fill will leave either old coolant or water in your system, depending on how you do the drain/flush.

Bill Dearborn

I agree. However, most people who do it themselves don't have access to an expensive coolant change machine so they end up like I do. Draining the system and refilling several times before the drainage runs clear. I estimate I use about 36 qts of water to make sure the drain runs clear so that would be ~8.5 gallons of water to throw away plus another two bottles to do the final refill. A lot of gallon jugs laying around if you use distilled water.

Bill

laconiajack

Do not use tap water, the fact that they use tap water at Bowling Green on the original fill is one reason you frequently read about people here on the Forum having to replace their failed Corvette waterpumps at very low miles (less than 100,000). Dex-Cool doesn't neutralize the minerals in tap water, and these minerals plate out on the dynamic sliding sealing surfaces of the waterpump mechanical face seal, causing seal face seperation and creating leakage paths for the coolant to escape through from the cooling system into the adjacent waterpump bearing (destroying it) and/or leaking out the waterpump drain hole. Incidently, coolant doesn't escape from the system due to evaporation, it is a totally closed system with an overflow recovery system. The only way you loose measureable amounts of coolant from the system is leakage past the waterpump seal, mainly but not totally caused by mineral and anti-freeze constituants plating out on and seperating the dynamic sealing surfaces of the waterpump seal.

RnLi

Prestone, or anyone else, cannot use the TM DexCool if it doesn't fit GM's EXACT formula.....unless licensing laws have changed.

Cruncher

Per GM, Dex-Cool does neutraliize the minerals in tap water. I used to keep a copy of what was written by GM. Should you have a problem with this, maybe you should contact GM for clarification.

JRfigo

I ended up going to the Chevrolet dealer and paying over $200.

The technician had the radiator drip out the old coolant. Then he washed with a hose the reservoir and then he added new coolant. He didn't use a special vacuum some of you mentioned, nor did he flush the radiator.

Also, the GM coolant he used was already premixed 50/50. I believe he only used 1 gallon. Is this correct?

What am I supposed to do here?

laconiajack

I don't have a problem with this, but they obviously do; thus all the early waterpump failures their customers experience. They can contact me if they want and I will explain to them why most Japanese automobile manufactures never fill their cooling system with tap water and recommend distilled or deionized water for refills.

R&L's C6

Make sure the reservoir is full to cold line when cold, and forget about it for another 5 years.

Cruncher

Hmmmm...mine takes 2 gallons of pre-mixed coolant.

Ketchum

JRFIGO> What you had done was a drain and refill. Thats more then likely what gets done to 90% of the cooling systems. In the Nissan store,Chrysler store and G.M. I ran service depts in that is what was done. Just drain and refill,clean reservoir. That came about with aluminum and plastics being used for radiators. Its also what most repair manuals call for as a p.m. I paid techs 1.0 hours to do such. We charged customers a maintance rate which was about half a repair rate. If repair rate was $88 we charged $45 for a coolant drain and refill. Plus coolant of course. These new fangled coolant machine did a much better job in a fraction the time. 20 to 30 minutes or so from the time tech opened the hood and hooked it up to the time putting coolant back in. I had two trucks one was a diesel done at a Quick lube after they showed me how it worked. I stood over both and watched from start to finish.

SUB VETTE

Just wanted to thank Brim for his detailed instructions. Changed my coolant today and used six quarts of distilled water which was exactly the right amount to get three flushes accomplished as he specified. Walmart material cost: $0.83 per gal for water, $13.84 per gal for Prestone Dex Cool.