BSE1956

I changed out the Dex-cool in my 5 year old (13K) C6 the other day.
Read a number of posts on this and checked the manual.
So, armed with a 5 gallon jug of super-purified water (my buddy uses super filtration for the tap water before it goes into his reef tank), a clean pan and 2 gallons of dex-cool, I got started;
-Jacked up the rear a little higher than the front to drain toward the radiator.
-Opened the petcock at the bottom, passenger side rear of the radiator.
- drained the system and got a little more than 2 gallons out. Color was a bit dark, nothing bad.
-filled with clean water and ran for 2 minutes, then filled the rest of the way, and ran until the temp got over 200 degrees.
-waited 20 min or so to cool, and then drained & repeated with clean water.
-after 2 "flushes" the water came out barely pink, so I added 1.5 gallons of dex-cool and then ran 2 minutes at a time and topped off with H2O till full. Used almost all of the clean water and then 50/50'd the remaining gallon of dex-cool.
This was a very tedious task...Back and forth....Run and cool off. Too many cycles to count. Very slow drainage and filling through the overflow tank.
The good news was that I had plenty of other chores to do around the house while waiting for cooling and draining. Planting, garage cleaning, detailing & other stuff.
My advice is to do this yourself, save money, & make sure it's done right (it's easy) but have plenty of chores or other things to do while waiting.
Total cost was about $30.00 for the two gallons of Dex-cool.
Total time from start to finish - about 4 hours.
Good luck!

Don-Vette

Nice write up!

AORoads

Good going, but I'd screw it up.

Red08

I changed mine last fall. Yes, it is a fairly slow process. Find something else to do while draining. Mine seems to run a couple of degrees cooler after the change.

haljensen

You added a full 2 gallons of Dexcool after draining and flushing? Since the total capacity of the system is 12.5 quarts the refill would only require slightly over 1 1/2 gallons of Dexcool.

Using 1 1/2 gallons of Dexcool gives very close to the 50% antifreeze/50%water that is required.

Gman in NC

Good write-up. Thanks. I'm planning on doing mine soon. Always something to do during the cool down periods.

BSE1956

I know it's a lengthy post, but read that I added 1.5 gal of dex-cool.

Dano523

If you are going to change the Dex cool, then change the T stat out at the same time.


As for it if take long or short to burp, all depends on if the T stat you bought has an air bypass channel or not.

No air by pass channel, and you have to wait for the T stat to get up to temp to open before the system will start burp.

With air by pass channel in the T stat, Air and small amount of fluid can pall through the T stat before it opens to not only cut down on the air pockets during the fill, but also to burp the system out quickly as well (will burp with the fluid cold).

The brass button in the flange of the T stat below is the air bypass channel. If you are determined to use a factory T stat without the bypass channel, the drill one with a 1/16" drill bit TDC of the flange instead (to make burping the system only take a few mins, verses the Factory T stat heating cycles to open up to even allow air to pass through it instead).

BSE1956

Great tip. Wish I knew this before I did the change. Thanks.

Joe B.

The factory stat, pictured, in my '12 LS3 has the "bypass channel". So does the 180* Stant 15158 I replaced it with.

victorf

^^^^Same here. Even my 9 year old '05 had the bypass on the OEM! But then, changed out to an 160 that came with the bypass when I mod'ed for more power. Unlike back in the days thermostats don't come with bypass but most old schools drill their own, most people I knew use 1/8" drill.

Each time to get my flush out water not to have visible tint residue, required 18 gallons of distill water flush over two days - no rush style and without removing block plugs. First time was on the 5 year mark, then twice more, followed with thorough flush after silicone hose install, then the following year, Dewitts install.

Thoroughly clean, takes time and distill water is cheap. I don't change out thermostat unless needed but to each their own.

RJRSW

I had the dealer do mine and they do a couple additional steps when they do it. They charged $89.95 and it did take over an hour to make sure that they had no air pockets before they would turn over the car to me. They said that the vettes are notorious for air pockets and if it is not done right it can overheat on the trip home. They sell and service a lot of vettes and I have been using them for over 20 years and they treat vette drivers very well. They even had the tech that did the work deliver the car back to me personally so he could explain what extra steps he had done to assure that there would be no overheating problems.

They added a cleaner to the system first that was circulated though till hot and then did a complete system flush to completely remove all old coolant and any contaminants loosened by the cleaner. They then refilled with Dexcool plus added the system conditioner.

1bdvet

I guess I took the easy way out, took it to the stealership, and had them use there machine to suck all the fluid out and service with fresh, and doing it that way no air bubbles, and no problems.

scottaolsen

That's interesting, because GM does not recommend flushing the cooling system unless there has been "catastrophic failure or extreme corrosion. This practice is NOT required or recommended for normal service operations" And they specifically say do not use a chemical if a flush is performed.

Under normal circumstances, GM only recommends the "drain and refill" procedure.

This is why I quit going to the dealer for service, though I have to admit it was due to the Chrysler dealership screwing my wife over and over for unnecessary "tune-ups", throttle body cleanings, and flushing on her van.


Tell the GM dealer to look up bulletin 2012-09-28 and ask for your money back.

CSixDude

Don't use tap water in any vehicle with an aluminum cooling system, no matter how well it is filtered.

City tap water is chlorinated, and will cause aluminum corrosion and pitting to occur.

You should only use pure DISTILLED water in your cooling system.