Coolant Purging Question

[Bigredo4]

I just changed my water pump on my 04 Siverado SS. The service manual says to open the bleeder screws when adding the Dex Cool, then close them after the fill. Where are the "bleeders" . The instructions are different from the 03's, I'm wondering if I can just follow those instead.

thanks

Bob

[Fireman31]

Refill/Purge instructions by Mr. P...............

 

1. Close the radiator drain valve (under the front bumper, driver's side);

 

2. Refill the engine with coolant - the SS cooling system refil capacity is 12 to 15-quarts (3 to 3.75-gals), and as a general rule you want at least a 50/50 mix of anti-freeze and water in the engine, if you live in colder climates you will want less water and more anti-freeze, the correct amounts will be charted on the back of the anti-freeze bottle; the chemistry doesn't have to be exact, give-or-take a half-pint is close-enough. Do not fill beyond the "FILL COLD" mark on the fill/overflow tank. (In my SS, I ended-up adding 5 quarts of anti-freeze plus 5 quarts of water.)

 

*Optional Step* - add a product to your anti-freeze called 'Water Wetter', highly recommended in ALL cooling systems, not too expensive and drastically improves the efficiency of the coolant. You will find this at speed shops or mail order houses (Summit Racing, Jeg's and the like).

 

THE FOLLOWING COOLING SYSTEM PURGE PROCESS IS CRITICAL, if you do not purge all the air from inside the engine you will have 'hot spots' or uncooled areas caused by these trapped air pockets in your engine heads, and aluminum heads will not tolerate this localized overheating, they will warp.

 

3. Start the engine and let it idle, immediately inspect for leaks (if you think you spot a leak, turn off the engine before it gets too hot to work on!) After one minute of idling, put the cap back on the fill/overflow tank;

 

4. Get the new thermostat to open by warming it to operating temperature; you will know that the thermostat has opened because the lower radiator hose (and radiator) will suddenly go from room temperature to almost scalding hot, and you can check for this by touch as the engine warms up. You can help the process along by gently increasing the RPM from idle to 3000-RPM over 30-second intervals. AFTER the new thermostat has opened turn off the engine (the lower hose will be hot to the touch, check it with your hand to be sure but don't burn yourself).

 

NOTE: During first warm-up you may notice that the temperature guage on your dash rockets well above the 220-degree mark - this is not a cause for immediate alarm, it happens because there is an air pocket blocking the hot coolant from reaching/heating the coil on the new thermostat and opening it. If this happens go ahead and let the engine continue to idle for an additional 3-4 minutes (no more) giving the thermostat its chance to open provided that the dash guage needle does not 'go into the red'. If the thermostat still fails to open after a few minutes OR the engine does begin to overheat (guage begins creeping into the red), turn off the engine and let it sit - after a few minutes of 'heat soak' the thermostat will eventually open on its own (even with the engine off) and then you can continue to the next step in the refill instructions.

 

5. SLOWLY remove the fill/overflow tank cap, BE CAREFUL IT MAY BE UNDER PRESSURE, if so it will try to spray coolant onto you; let the pressure bleed off before completely removing the cap;

 

6. Restart the engine and let idle again for at least one minute with the fill cap OFF; this burps the trapped air out of the cooling system.

 

7. Refill the fill/overflow tank to 1/2-inch above the "FILL COLD" mark and screw the cap back onto the fill/overflow tank.

 

8. Drive the vehicle a few minutes (to the store and back? ) and check the coolant level in the fill/overflow tank when you return.

[kelleyperformance]

very good instructions.

 

theres a faster, more efficent way but requires a tool or machine. you can pick one up from sears, i beleive (i get mine from snap on or matco). its basically a tool that goes into the overflow tank, sucks all the air out till the hoses collapse, and then you let the built vaccum pressure syphon the new coolant in. thus leaving no air pockets and adding just the right amount of coolant.

[Bigredo4]

very good instructions.

 

theres a faster, more efficent way but requires a tool or machine. you can pick one up from sears, i beleive (i get mine from snap on or matco). its basically a tool that goes into the overflow tank, sucks all the air out till the hoses collapse, and then you let the built vaccum pressure syphon the new coolant in. thus leaving no air pockets and adding just the right amount of coolant.

I did it according to Mr P..... instructions which was close to the manual other than the bleeder screws. I saw the bubbles coming back to the tank, the temperature stayed at normal so it looks OK. Thanks for the replies and the insight.....

Bob

[Bigredo4]

I did it according to Mr P..... instructions which was close to the manual other than the bleeder screws. I saw the bubbles coming back to the tank, the temperature stayed at normal so it looks OK. Thanks for the replies and the insight.....

Bob

Some more questions; after driving the SS about 5 miles or so I checked the hoses. It doesn't overheat as the gauge shows the temp. normal. The top radiator hose is hot and can be depressed. The lower radiator hose isn't hot to the touch and also can be depressed. Both the hose going to the throttle body is hot and hard and the hose going to the surge tank (near the top of the tank, not the puke hose) is hot and very firm when squeezed. Do you think I have air in the system? The level in the tank is good.....

Thanks again