flush and fill cooling system - 2003 z06

[donny]

Good day. Does anyone have any experience flushing the cooling system on a LS6? I have experience on the old school blocks, but I thought it would be good to ask, as there is a sticker indicating that the service manual must be followed, or engine damage will occur!

 

[mqqn]

Hi donny -

I just open the drain cock and let 'er drain.

Then refill.

Not the most effective way, as some gets left in there, but if you do it regularly I think it is fine.

I don't have not flushed the system on either car.

best regards -

mqqn

 

[tghawkins]

I usually drain my system when it is cold and not under pressure. If you leave the overflow tank cap on, and open the drain valve on the radiator, it will siphon all the coolant from the overflow along with what is in the radiator. Just draining from the radiator will get 8 of the 12 quarts in the system. Unless your coolant looks dirty, you probably do not need to flush the system, in which case, you can just add a 50/50 mixture of antifreeze an distilled water until the system is back to the full mark.
If you want to flush the system, you can always just add distilled water and circulate it until it comes out clean, then add enough coolant (considering the 4 quarts in the block are pure water) to bring the mixture back up to 50/50. A 50/50 mixture should be about 6 quarts of antifreeze for the 12 qt. system, so if you have 4 qts. of water in the block, you can add 6 quarts of pure antifreeze to the system, and then fill it the rest of the way with distilled water, and you should be back to 50/50.

 

[donny]

thanks so much. but there is nothing unique to performing this procedure on a block newer than 1986? why therefore is there the sticker in the engine compartment warning of engine damage?

 

[tghawkins]

thanks so much. but there is nothing unique to performing this procedure on a block newer than 1986? why therefore is there the sticker in the engine compartment warning of engine damage?

I have a 2003 chassis service manual and the only warning under Draining and Filling the Cooling System is that "failure to follow the correct procedure could result in a high or low coolant level and vehicle damage could result."

I think the main concern is that you need to make sure you let the thermostat fully open to fill the system, and recheck the level in the overflow tank after the engine has cooled all the way down to make sure the level has not dropped below the "FULL COLD" mark.

For reference, here is an excerpt from the manual...

1. Close the radiator drain cock. Tighten to 18 lb in.
2. Slowly fill the cooling system with a 50/50 coolant mixture of deionized water and DEX-COOL.
3. Install the coolant pressure cap.
4. Start the engine.
5. Run the engine at 2000-2500 RPM until the engine reaches normal operating temperature.
6. Allow the engine to idle for 3 minutes.
7. Shut the engine off.
8. Allow the engine to cool.
9. Top off the coolant as necessary.
10. Rinse away any excess coolant from the engine and the engine compartment.
11. Inspect the cooling system for leaks.

That's it.

NOTE, I had a 1996 SS Camaro with the LT1 engine, and it had vent screws that had to be opened to make sure the coolant pushed all the air out. Obviously, if you left air pockets in the engine, it could cause hot spots and engine damage. There are no other special notes for the LS6 in the manual.

 

[vette747]

I have copied the Drain and Flush from the shop manual on my web site. Go to http://pages.videotron.com/vette747/

and scroll down to the WaterPump link.