Coolant Change Procedure Help
Thread Starter
Instructor
Joined: Dec 2003
Posts: 220
Likes: 42
From: Blairstown New Jersey
Coolant Change Procedure Help
Any tips on the best way to do a thorough coolant change on an '02 Z06? Any hidden petcock/drain locations? What is best coolant to use? THANKS MUCH. 
Melting Slicks
Joined: Sep 2006
Posts: 2,041
Likes: 4
From: Rockford Illinois
Do you want to completly drain the block etc or just the radiator etc?
I usually dis connect the lower hose and let it drain, then pul the radiator out and flush it with water. I would use Dexcool, maybe even throw some water wetter in there to help keep the cooling down.
Drifting
Joined: May 2006
Posts: 1,616
Likes: 1
From: Minnesota
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
5 years or 150,000 miles. If coolant looks okay there is no need to flush (from Shop Manual). Drain valve is under radiator on passenger side, only turn it 90 degrees and pull it out. If you turn it more, you will shear the pin and have to buy a new one (about $5 at NAPA). I jacked up car to get at drain plug, then lowered it to drain out all but 2-3 quarts.
Filling involves using 50 - 50 Dexcool mix with distilled water, reving engine to 3,000 rpms, and topping off 2 more times.
Filling involves using 50 - 50 Dexcool mix with distilled water, reving engine to 3,000 rpms, and topping off 2 more times.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,820
From: Charlotte, NC (formerly Endicott, NY)
You can get by without the 50/50 mix. Flush the system several times until the water runs clear. Drain until you can't get any more water to come out, close the drain, then add the appropriate amount of coolant and top off with water. It only has to be drinkable tap water not distilled water.
Bill
Bill
Burning Brakes
Joined: Oct 2004
Posts: 925
Likes: 4
From: EXTON PA
water mineral concern?????
You can get by without the 50/50 mix. Flush the system several times until the water runs clear. Drain until you can't get any more water to come out, close the drain, then add the appropriate amount of coolant and top off with water. It only has to be drinkable tap water not distilled water.
Bill
Bill
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Oct 2006
Posts: 445
Likes: 0
From: State of Perplexity California
Thread Starter
Instructor
Joined: Dec 2003
Posts: 220
Likes: 42
From: Blairstown New Jersey
Coolant Change
Thanks for the tips. I read somewhere that the Dexcool was trouble, and shouldn't be left in for long. I have run coolant for well over 100,00 miles and who knows how many years in other vehicles, but I ain't takin' any chances on this one.
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
I have 4 cars that run Dexcool. I have not had a problem with my Z06 or Impala, but on our Malibu, the overflow tank builds up an oily sludge that nothing will completely remove. The coolant comes out clean, but the whole system is coated with a brown paste. I gave up on cleaning the overflow tank, and just replaced it.
Whether you use distilled water or "tap water" should depend on how many minerals are in the local water. Our water will form solid deposits in the radiator so I always use distilled water. If you want to know just how bad your water can get, take a look in your home water heater the next time it is replaced. Mine had an inch thick crust on the walls.
Last edited by TEXHAWK0; Feb 19, 2007 at 11:49 PM.
Drifting
Joined: May 2006
Posts: 1,616
Likes: 1
From: Minnesota
You will hear many people say tap water is fine. I think in a lot of cases it is (even at the Vette factory) but it does depend on the area. To me since distilled water costs about $1.25 a gallon it was a pretty easy decision.
Long as you're doing it why not use distilled 
Burning Brakes
Joined: Aug 2000
Posts: 1,132
Likes: 1
From: Morganton, NC, USA
Draining the radiator only removes about half the coolant in the system. I made a hose adapter 8" long from 2" radiator hose. A PVC adapter on one end allows me to connect the male end of a garden hose. Hose clamps hold it to the fill fitting on the expansion tank and keeps the hose adapter in place. Running the garden hose will backflush the system somewhat, and I also turn on the engine so the water pump circulates all the water through the block and heater. After the exit water is clear, I pour 3 or 4 gallons of dehumidifier condensed H2O into the expansion tank while allowing the radiator to drain. I hope this pushes out most of the city water, or at the very least dillutes it. After the radiator stops draining, I add 6 1/2 quarts of Descool through the expansion tank and run the engine to mix. I now figure I have a good 50-50 mix as the total system capacity is listed as 12.8 quarts. I figure this is a lot better than draining the radiator and simply re-filling with 50-50 mix.
