fgriff1

Hello,

2006 C6 base 6.2L
I did a search and came up with several ways to do the drain flush.
Is the following correct? If not what is the correct way?

1.Drain(from Petcock), refill with water?, run hot, cool, drain again
2.Refill 50/50 mix DEXCOL w/Distilled or drinkable(manual Recommends)?
3.After filling, start car and continue to fill through coolant surge tank till it reaches full mark
4.Stop car, let cool and make sure collant at FULL COLD mark
5."Burp" the system, how?

Thanks in advance
Frank

Ragtop 99

Owners manual allows for tap water, but many people use distilled water to not introduce any sediment.

My F-Body occasionally needed burping, but I found the vette system self burps just by letting the car idle to get hot enough to bring on the fans and shutting down and restarting when cool.

fgriff1

Thanks Ragtop99

So i guess step 3 gets rid of the air(fill while running)? Also are the steps i outlined correct?

thanks

Ragtop 99

yes, your procedures describe what I did. I run a mix that's more like 60/40 water/coolant with a 160 T-stat, but that's a different conversation.

thomastl

Proceedure is correct except for the fact that you don't end up with a true 50/50 mix. Remember that the engine block, heater core, hoses, etc.. all have coolant in them that is not drained by this proceedure. What is left in there is old antifreeze and water mixture that is now deluted by an additional 2 quarts or so of water which is all you can get out of the radiator.

Here is my proceedure. Gets rid of a lot more coolant and allows you to flush the system with fresh water better.

1. With engine cold, remove the petcock to drain radiator.
2. Disconnect lower radiator hose at thermostat and remove thermostat to allow coolant system flushing.
3. Disconnect upper radiator hose (either end).
3. Disconnect one of the heater hoses.
4. Flush the engine and heater core thru the disconnected heater hose and connection until the water runs clear out the thermostat housing.
5. Flush the engine and radiator thru the upper radiator hose and connection until the water runs clear out the thermostat housing and radiator petcock.
6. Let drain.
7. Using an air compressor and blow-off tool, blow air thru the hoses and connections to force as much water out of the system as possible.
8. Put everything back together.
9. Check your owners manual for the cooling system capacity (11.9 quarts I believe).
10. To ensure you end up with a true 50/50 mix - add 6 quarts of of 100% coolant (not 50/50 premix).
11. Top off system with water. You will not be able to get 6 quarts of water in the system due to water being left in the block.

Longer & more complicated process but you ensure that you have flushed the cooling system good and that you end up with a true 50/50 mix in the end.

Ragtop 99

^^^Nice write-up.
Use an antifreeze tester to verify you hit your coolant ratio. I test it after I've driven it for 20 minutes and the system is reasonable well mixed. I let it cool down before testing.