It seems like yesterday when I bought my '05 Vette, however, it has been 5 years on Monday. The coolant is "required" to be changed. I have the shop manual and it states to drain the coolant, replace with water and run, drain, repeat if necessary until the drained water is clear. I plan to mix the Dex-Cool with distilled water. My concern is that the entire system may not be drained before I put in the mix. On my '64, it is easy to pull the block drains and heater core. Has anyone out there been there and done that yet and how did it go? As always thanks to you all. An early Happy Easter and to those who celebrate the reason for the holiday, HE IS RISEN!

 

hey dave, yes, you can drain the block. the bad news is a little work is involved. on the pass. side of the block, you have to remove the starter to get to the drain plug. on the driver's side, there is a big plug in the forward side of the block. takes a very large allen bit to unscrew out, going thru the lower control arm. be careful re-installing it. it may cross thread if you are'nt. i use a vaccumn pump on the cooling system to refill it just like the factory does. this way you have no airlocking issues. good luck

 

My advice would be to do this.

Buy twice as much DexCool as you need. Drain all the coolant you can get out by opening the petcock. Don't flush it with water at all. Just drain it all out. Now refill it back up with 50/50 DexCool and go drive it for an hour or so. Then let it cool off and repeat the drain/refill process.

This way, you won't have any leftover plain water in your system, which forces you to try to "guess" at what the final concentration is. You are essentially using the 50/50 DexCool to flush out the system.

If you're really ****, do the fill flush an additional time. Each time you flush/refill, you are getting a smaller and smaller percentage of the old original fluid out. If on the first flush, you get 80% of it out, then the remaining 20% gets mixed in with the new, and then when it all mixes up and you do a flush again, the leftover 20% in the engine, is made up mostly of the new fluid you added (80% new 20% old). Each time you repeat, the percentage gets smaller. The best part is you will have exactly 50/50 coolant/water mix in your car when you get done, since you didn't use distilled water to flush. Yea, you will waste some new coolant and it will cost a little more, but you won't have to mess with trying to drain the block.

By the way, I would recommend using the GM Dexcool and not mixing any other brand/type coolant with it. DexCool (sometimes called DexClog) is very finicky about what it will mix with. If you buy concentrate and have to dillute it, be sure to only use distilled water. Never put tap water in. Not only does it contain minerals that can cause deposits, but most cities chlorinate and/or florinate the water, and chlorinated water can cause aluminum corrosion.

 

I have not done the vette yet but the 'trick' I have always used on all my other cars through the years is to NOT mix antifreeze with water when refilling the system. It's unlikely that you get 100% of the water out after flushing, so a 50/50 mix going in will be diluted - and it's anyones guess as to what concentration you really have. What I do for the final flush is use distilled water. After flushing that I pour in 1/2 the systems capacity in pure antifreeze. Then just top off with distilled - you are guaranteed to be 50/50 doing it this way. I always double check with an antifreeze tester and it comes up something like -30 which is about right. IIFC, the vette doesn't have a radiator cap and you need to fill it though the expansion tank...that should be interesting.

Not that I would do it this way, but if you read the instructions on just about any bottle of antifreeze it will say to open the drain petcock on the bottom of the radiator, let it all drain out, close petcock, refill with a 50/50 mix of water and antifreeze - that's it. From what I have seen, you would have left about 50% of your old coolant in the system doing this. Maybe they think 50% old is better than 100% old.....

 

Blessed Easter to you as well David.

I'm planning on changing mine out as I have an 05 too.
John

 

Just had mine done at dealer 2005 34,500 miles and watched them do it. They do it just like stated above in last paragraph. Tech told me you cannot flush it or they can't with machine because of the system itself the plastic reservoir is like the cap on top of a radiator on a regular car so flushing it through the bottle wouldn't work. So he lifted car and let radiator drain from the highest point then added one gallon of Amsoil Anti-freeze and one gallon of distilled water both supplied by me. He ran the car with heater on and watched temp gauage to make sure to get air out of the system.

The old anti-freeze was still very colorful red. I thought Dex-cool is orange.

 

If you want to know how much of the old coolant you got out, all you have to to is measure how much comes out and then check the capacity spec in the manual and you'll know how much of the old coolant is still in the car.

All you really need to do is drive the car to get the old and new mixed up real good and then repeat the drain/refill cycle. It's pretty simple.

 

I have an 07 and was thinking about doing it, just did the diesel in the boat. Is 5 year the recommended change interval?

 

mine is an 05 and i need to get it done too.

 

Personally, I don't think I will go 5 years on my car. There have been many documented problems with DexCool and even though it says it is good for 5 years, I wouldn't leave it in that long.

Also, be aware, DexCool can and will cause problems (clots/clogs/crystal formations) if mixed with the wrong coolant. If you are changing brands, you need to do a TOTAL system flush to get ALL the old DexCool out. Don't ever mix DexCool with another brand/type. I don't even trust some of the ones that claim they can be mixed with DexCool. DexCool is very sensitive coolant to what it will mix with.

The safest thing to do would be to go to the GM dealer, and buy DexCool and use it so that you don't run any risk of having compatibility issues. Your other option would be to TOTALLY drain and FLUSH out the system and then switch to something else.

If you want to have some fun, google "DexCool Problems" and then read some of the stuff you find about it. Here is a site with some good info about it.

http://www.imcool.com/articles/antif...l-macs2001.php

Here is another one.
http://www.imcool.com/articles/antif...le-Excerpt.pdf

 

I'm not sure why you even need to completely flush it at all. Been doing this with my cars for 25 years and never a problem. Basically just drain it, tighten up the petcock, refill with 50/50, burp it for air and go about your business. You could conceivably do this, drive it for a week, repeat the process and you'll have a very small percentage of the original coolant remaining. Gets expensive.

I need to do mine. I have two jugs of Dexcool sitting in my garage cabinet.

RMX

 

My question is: on the Vette, where do you refill it? I am assuming the overflow tank, but boy does that look like it would take forever. Those outbound hoses look TINY.

Is that correct?

RMX

 

Yep, it takes a while.

 

Dave, use a voltmeter to check the condition of your fluid before you change it. If you get any voltage, then it is acidic. That's the time to change it.

Are you changing your brake fluid also?

 

Why not just use all distilled water instead of anti-freeze in the above process so it is less expensive and then you will know when anti-freeze is completely gone when it's clear. Then do the 50/50 distilled water and anti-freeze?
At $33.00 to $25.00 a gallon Amsoil fluid can get to be a very expensive flush using this method.
Dealership told me you cannot use a machine to evacuate all fluids and you can't get rid of all the old coolant.

 

with what Fred H. said.

 

Whatever method you use, after adding the new DEX and distilled water, run the engine at 2000rpm for 2 minutes. This will insure that you get out all the trapped air. Run the car a mile or so and top off with a 50/50 mixture as required.

 

Thank you all! Yes, Norty, I will be changing the brake fluid too. See you Tuesday.