HT4100 4.1, 4.5, 4.9 Discussion, Best way to bleed the cooling system? in Cadillac Engine Technical Discussion; Flushing out the radiator and installing a 160 degree thermostat. What's the best way to bleed the system?...
Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
Re: Best way to bleed the cooling system?
The way I do it is to fill the engine with the thermostat removed, install thermostat then refill radiator slowly. Start engine and bring the idle up to approx 1500 RPM and hold it there. As the thermostat opens, the fluid level will drop. Holding it at 1500 add coolant till the rad is full, then without lowering the engine speed install the cap. Best done with 2 people. Then I drive the car for 15 /20 min. and top off the recovery tank as necc. I also have the climate control at 90 degrees displayed to purge the heater core of air. Keep in mind a 160 thermostat will allow you to advance the timing but at a mileage penalty. Engines get better mileage and perform better at close to 200 degrees. This will also affect the heater output. And again, put the year and model in your profile!