Originally Posted by BillBoost37
Let me get something clear.
For this site: when advice is given, the safe methods are given. Personally and individually we may practice other methods. However for the good of all on the site and many that are not normally under the hood, safe is the best information.
Safe procedures being transferred to other members is each members responsiblity.
There is nothing here to debate. Safe is the only advice that should be conveyed openly.
Are you responding to something I posted?
Let me quote from the 1998 Service Manual from GM for the H bodies, Bonneville, Eighty-Eights, LeSabre. The 1993 service manual is the same IIRC. If needed I can copy it as well.
From Service Manual:
Draining and Filling Cooling System
Caution: As long as there is pressure in the cooling system, the temperature can considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the PRESSURE CAP while the engine is hot and pressure is high will cause the solution to boil instantaeously --possibly with explosive force-- spewing the solution over the engine, fenders and the person removing the CAP.
1. Refill the cooling system with GM Goodwrench DEX-COOL or Havoline DEX-COOL. To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection lvel at -37 degrees C. Use a solution that is no more than 70 percent antifreze.
2. Place the heater and A/C control in and A/C mode except MAX and the temperature in the highest setting.
3. Allow the engine to continue idling until the lower radiator to coolant pump hose is hot.
4. Cycle the engine speed up to about 3000 rpm and back to idle five times.
Slowly open the bleed valve on the rear of the thermostat housing for approximately 15 seconds to expel and trapped air in the cooling system.
5. After the air has been expelled, fill the radiator. Install the radiator pressure cap, making sure the arrows on the cap line up with the coolant recovery tube.
6. Allow the engine to cool to outside temperature. Check the coolant level in the reservoir.
End service manual quote. Some trademarked are included in the above quotes.
GM'* instructions are clear to me.
I follow their method. The retention of any air in the DEX-COOL radiator with the movement of the coolant to mix them is a factor in sludging from DEX-COOL that happened with certain models of cars, according to my service manager at the Buick dealership. I am careful to remove all air. Whether you wish to do it cold or following GM'* procedure is up to you.