Air in cooling system of 87 300E
 

OK, I saw the coolant light on the dashboard and put about 3/4 of a gallon of coolant into the reservoir. Later after a hot run I stopped the car in the garage and heard a bubbling sound coming from under the battery area.

It appears I have air in the system so I will elevate the front of the car and remove the reservoir car to run the car for a bit. My questions are...

1. How long should I do this?
2. Should I also loosen the bleeder screw next to the dipstick?
3, Should I also turn on the heater?
4. What are my chances that my head gasket is fried?

Many thanks in advance.

bump...

Save the effort.

With engine cold, squeeze the upper radiator hose flat, then crimp the small line from rad to reservior closed. Release the upper rad hose. Coolant will be sucked out of the tank into the block. Refill tank, and repeat, filling as necessary, until the level doesn't drop in the tank anymore.

This will get nearly all the coolant into the head, where it belongs.

You must then run the heater full hot until the air purges out of the heater core (this may take several hot/cold cycles). Top off tank as requried.

You should also check the aux pump and heater hoses (under the battery and next to the brake booster) for leaks.

Peter

Removing the bleeder screw when you fill up coolant helps fill about 90% of the system. But you still have to run the engine and top up until the coolant level stops dropping in the overflow tank. Make sure you run the heater to purge that circuit also.

Sorry it took me so long to get back to these great responses. I'm still fearing the dreaded head gasket diagnosis but I want to get all the air out before I jump to that conclusion. The question I still have is...where did all the water go in the first place? I realize that replacing the coolant last fall and not getting all the air out of the system may be the root cause of all this but I'm hoping that using these techniques will solve the problem. Thanks guys.