Dans-Z06

Well my coolant has aged past the 5 year mark.

Me and my buddy were working on his car doin the breaks and i brought up that i should work on changing my coolant.

My buddy used to have a z06 and told me if it aint broke dont fix it. He said he changed his coolant and had overheating issues. To get rid of the air pockets causing the overheating he said he had to run his car w/ no cap for like 5 hours to get all the air out.

....so the question is. Should i change my system?

Heres how i do it

Drain coolant from radiator plug and plug it back up up.
Fill w/ water, close cap, run engine w/ heat max on until thermo opens, drain and plug again
Fill w/ water, close cap, run engine w/ heat until thermo opens, drain and plug again.
Fill w/ 50/50 mix of coolant (will be using DEX-COOL)
Run w/ no cap for 5 min
Put cap on, leave car still running w/ heat until thermo opens. Let it cool, check level.

That way, the old system would be completely clean and the new stuff would be everywhere but going back to what my friend. He said i will have air pockets and a half causing overheating.

I also usually did my filling through radiator cap but this car doesn't have one. The coolant resavoir will do the same job rite?

What do you DIY guys think?

ALLEGRO

I changed mine at nearly 6 years. I only have 27K on the clock, but decided to change it and check its condition.

It looked just like what I put back in. There was no color change or debris in what I removed.

It takes a while to do this. I cycled 5 times with water before I got clear draining. Refill is different in that we have no "radiator cap" but a resevior cap. Pretty much it is as you describe, and after the T stat opens you will burp all the air out. It did take a couple of days before I got the res level where I wanted it.

All in all, it is just peace of mind !

Good luck

sorbet70

my coolant is at the 7yr mark with 14k mi,and it looks brand new......

aspenz06

My coolant was 7 years old when I changed to the 160 deg. thermostat, so I changed the coolant at the same time. No problems so far.

VetteDriven

If it looks ok, forget it.

Turbopower87

why not just use a turkey baster to pull it out of the tank and leave the little bit still in the system. Should be no problems with air like that. If it bothers you to have some old fluid left, do it again a week later.

Dave68

One of the main reasons why so many people have had problems with Dex-Cool is they neglected to change it when recommended by the factory. I would not tempt fate - change it, NOW!

killain

I only have 12K miles on my 2003 50th AE and I had the coolant changed last year. The mechanic at the dealership I use is a master tech and works on corvettes only for this dealership. He was telling me that changing the Dex-cool is one of the MOST important issues you can do for your corvette. And that a lot of the leaking manifold problems that some people have had in the past is due to running the coolant for too long. It's cheap insurance for the health of your LS-1. To me, I would never let the recommended changing of fluids go. I got hurt at work a couple of years ago, and as such I can't drive my Corvette as much as I'd like but, I change the oil every year even if it's only been run for say 2000 miles. I paid close to 50K for my car and I damn sure arn't going to try and cut corners on maintenance !

Vetteman Jack

Factory says the coolant is good for 5 years or 100K miles, whichever comes first. If it were my car, I'd be changing the stuff.

stormrider

I didn't change mine at 5 years and it cost me $700 plus for a new radiator because two of the tubes where so clogged up the shop couldn't even run a rod through them.

Tigershark3

I've been changing mine every two years regardless of the miles. Havoline's Dex Cool and distilled water. I just pull the bottom hose off of the radiator. That's a whole lot easier than trying to get that Cheezy drainplug loose. $.02

sorbet70

Dans-Z06

Hey DIY guys, is my method correct?

Durring the 100% water flush period, the water wont boil right?

Any air release hoses? My old car had 3.

Oh 2 Fun

Dan's-Z06....from the responses, it sounds like you are way ahead of the curve here. Without a radiator cap, I wonder how difficult it might be to reverse flush the system like a "normal" system.

The last time I flushed an engine, I had the waterpump off and it was way easy!

slothy

id change it

Wheelyneat

Is there a complete DIY or a reprint of the factory service procedure somewhere on the site? I want to make sure I get all of the air out of the system.

Red Rochester

87SAM

From the 2000 Service Manual:

Draining and Filling Cooling System

Caution
With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.
NOTICE
When adding coolant, it is important that you use GM Goodwrench DEX-COOL® or HAVOLINE® DEX-COOL® coolant. If Coolant other than DEX-COOL® or HAVOLINE® DEX-COOL® is added to the system the engine coolant will require change sooner; at 50 000 km (30,000 mi) or 24 months.
Notice
DO NOT use cooling system seal tabs, or similar compounds, unless otherwise instructed. The use of cooling system seal tabs, or similar compounds, may restrict coolant flow through the passages of the cooling system or the engine components. Restricted coolant flow may cause engine overheating and/or damage to the cooling system or the engine components/assembly.
Drain and Fill Procedure
Important
If the procedure below is not followed a low or high coolant level condition and/or vehicle damage could result.
1. Park the vehicle on a level surface.
2. Follow the steps below to remove the radiator surge tank fill cap:
o Slowly rotate the cap counterclockwise1/4 turn and then stop. Do not press down..
o Allow any residual pressure, indicated by a hissing sound, to be relieved.
o After all hissing stops, continue turning counterclockwise to remove the cap.
o To tighten the cap, use hand tight pressure only.
3. Open the radiator drain ****.
4. Allow the system to drain completely.
5. Inspect the engine coolant:
o Discolored -- follow the flush procedure below.
o Normal in appearance -- Continue with the next step.
6. Close the radiator drain ****.
Important
When filling the cooling system use a 50 to 60 percent concentration with DEX-COOL® coolant.
7. Fill the system through the surge tank opening.
8. Fill half the capacity of the system with 100 percent DEX-COOL® coolant.
9. Slowly add clean drinkable water to the system until the level reaches to the base of the neck.
10. Start the engine.
11. Idle engine for 1 minute.
12. Install surge tank cap.
13. Cycle the RPM, idle to 3000 in 30 second intervals until engine coolant reaches 99°C (210°F).
14. Shut off the engine.
15. Refer to step 3 above to remove the surge tank cap.
16. Start the engine.
17. Idle engine for 1 minute and fill surge tank to 1/2 inch above COLD FULL mark on the radiator surge tank.
18. Install the surge tank cap.
19. Cycle the RPM, idle to 3000 in 30 second intervals until engine coolant reaches 99°C (210°F).
20. Shut off the engine.
21. Top off coolant as necessary, 1/2 inch above FULL COLD mark on the radiator surge tank.
22. Rinse away any excess coolant from the engine and the compartment.
23. Inspect the concentration of the coolant.

Flush Procedure
Important
Do not use a chemical flush.
1. Block the drive wheels.
2. Place the transmission in Park or Neutral.
3. Engage the parking brake.
4. Run the engine until the thermostat opens.
5. Stop the engine.
6. Follow the drain and fill procedure using only clean drinkable water repeat if necessary until the fluid is nearly colorless. Refer to the drain and fill procedure.
7. Fill the cooling system. Refer to the drain and fill procedure.

Wheelyneat

MANY thanks for supplying the factory service procedure! Is this forum the greatest, or what?

Vega$Vette

If it ain't broke don't fix it. Of course the manufacturer says change it. They're just trying to sell more stuff