Things to try before blocking testing.
The Radiator cap should hold 15-16lbs of pressure for a period of five minutes before any leak down.
I would replace the cap first.
Another thing often over looked is the fan clutch. With the miles you have on your vehicle I would check for proper operation of the fan clutch.
Also because of the miles you show I would not rule out a water pump. Aerostar water pumps have very thin cheap impellers and if the cooling system has been neglected the impeller could be bad.
If all these suggestions fail to cure your problem then proceed with the block test.
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Thursday, July 24th, 2008 AT 10:55 PM