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Old 08-06-2006, 10:02 AM
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Join Date: May 2001
Posts: 145
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.
1987 300E
1967 Jaguar E-type Series I, 2+2

Last edited by Thom Pintello; 08-06-2006 at 10:08 AM.
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Old 08-06-2006, 11:19 AM
Registered User
Join Date: May 2001
Posts: 145
1987 300E
1967 Jaguar E-type Series I, 2+2
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Old 08-07-2006, 01:00 AM
Registered User
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
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.

1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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Old 08-07-2006, 02:22 AM
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Join Date: Apr 2002
Location: Dallas Area
Posts: 392
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.
1986 300E (3/2002) Rear ended and totaled (10/2009)
2000 Xterra (5/2000)
1992 400E (11/2009) -Sold
1986 300E (12/2009)
2004 E500 Wagon (6/2013)
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Old 08-08-2006, 10:09 PM
Registered User
Join Date: May 2001
Posts: 145
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.
1987 300E
1967 Jaguar E-type Series I, 2+2
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