Flushing coolant on C5
Thread Starter
8th Gear
Joined: Sep 2007
Posts: 8
Likes: 0
Flushing coolant on C5
I'm pretty mechanically inclined & the owner of my first vette. Is flushing the coolant system a job that can be done at home? Or something that is a major pain in the behind to even reach the petcock to drain the antifreeze? The site here is great. Thanks for the help
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
Should be an easy job. The drain is on the passenger side, lower corner of the radiator. You can fill with fresh water and run the engine until the water comes out clean, then add the right amount of coolant to get the correct 50/50 mixture.
I think the system holds about 12 quarts, and you can drain about 8 quarts, so just add 6 quarts of coolant and top off with water, preferably distilled water.
Instead of going through multiple drain/fill cycles, I usually just drain what I can and refill with a 50/50 mixture. I change the coolant at least every 2 years, so I figure a complete flush is not necessary.
I think the system holds about 12 quarts, and you can drain about 8 quarts, so just add 6 quarts of coolant and top off with water, preferably distilled water.
Instead of going through multiple drain/fill cycles, I usually just drain what I can and refill with a 50/50 mixture. I change the coolant at least every 2 years, so I figure a complete flush is not necessary.
Burning Brakes
Joined: Mar 2003
Posts: 1,156
Likes: 2
From: Arlington VA
I'm pretty mechanically inclined & the owner of my first vette. Is flushing the coolant system a job that can be done at home? Or something that is a major pain in the behind to even reach the petcock to drain the antifreeze? The site here is great. Thanks for the help
Personally, I am a firm believer in having a cooling system flush done using a flush machine every 2 years or 24K mi. I like the BG flush system but know there are other systems out their like Castle that do the same thing. These systems capture the old coolant, flush the system with chemicals to remove any deposits, and then replace with new coolant. Good luck with your project.
Race Director
Joined: Mar 2007
Posts: 16,154
Likes: 0
From: Kali
St. Jude Donor '11
First, I am sure you can change the coolant at home. I have seen posts from folks that do it all the time. I recall reading post for jacking the car up a certain way to ensure all the air is evacuated out of the system. The biggest issue is that if you plan to keep the factory fill Dexcool coolant in the system, you must be sure to get all the air out or you run the risk of the Dexcool sludging in the cooling system.
Personally, I am a firm believer in having a cooling system flush done using a flush machine every 2 years or 24K mi. I like the BG flush system but know there are other systems out their like Castle that do the same thing. These systems capture the old coolant, flush the system with chemicals to remove any deposits, and then replace with new coolant. Good luck with your project.
Personally, I am a firm believer in having a cooling system flush done using a flush machine every 2 years or 24K mi. I like the BG flush system but know there are other systems out their like Castle that do the same thing. These systems capture the old coolant, flush the system with chemicals to remove any deposits, and then replace with new coolant. Good luck with your project.
Burning Brakes
Joined: Apr 2007
Posts: 763
Likes: 1
From: Oceanside Ca
Aw, come on now, NUTZ?
And you are probably insanely jealous that the voices are talking to me, HUH!
Team Owner
Joined: Jun 2007
Posts: 30,770
Likes: 41
From: Down the Shore New Jersey, Elev.3 feet
St. Jude Donor '17
Hey...I have 13K on my vette and the oil has been changed 6 times ! 
Want to know the real reason why...oh its a good one....good and dumb !
The dealer gave me coupons for three free oil changes but.....ready cause here it comes....I had to use them all within ONE YEAR ! So I DID!
Want to know the real reason why...oh its a good one....good and dumb ! The dealer gave me coupons for three free oil changes but.....ready cause here it comes....I had to use them all within ONE YEAR ! So I DID!
Pro
Joined: Oct 2004
Posts: 538
Likes: 0
From: Edmond Ok
My 2 cents, yes it is an easy job, drain plug on the radiator, drain, run fresh water, drain again. However I would recommend distilled water and mix antifreze to your location, 50/50 may be too much in south florida and not enough in Maine. You can buy a device that measure the freeze point at any auto store (Sr. Moment, forgot what it is called) Glycol does not transfer heat as well as water, minimize the glycol. I mix mine to a freeze temp of -15 F to - 20 and every 50k miles.
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
Burning Brakes
Joined: Mar 2003
Posts: 1,156
Likes: 2
From: Arlington VA
Dexcool is a 5 year coolant. I did not flush mine until my car was 4 1/2 years old. Disregard my recommendation about 2 years 24K. I do this on my others cars that run normal Ethyl Glycol coolant. My recommendation regarding using a flush machine stands. You can extend the intervals with the Dexcool. Sorry.
