1999 Ford Ranger Coolant

1999 FORD RANGER
90,000 MILES • 6 CYL • 4WD • AUTOMATIC
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AGILEMUTS
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The coolant in my Ranger flows into the coolant reservoir when it warms up and won't flow back when it cools. I put on a new radiator cap, new thermostat, had the system flushed out and pressure checked, they said it was good. If I don't drain and put it back in the radiator it will blow the lid off the reservior spill coolant everywhere. Any ideas?
Jan 28, 2010 at 7:37 PM
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MHPAUTOS
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Hi there,

This is normally a faulty pressure cap, as the coolant warms and expands excess coolant flows into the header tank, as the system cools and a partial vacuum forms in the block, coolant is forced back into the engine by atmospheric pressure acting on the head of coolant in the header tank, you will either have a faulty cap or a leak in the system somewhere.

Mark (mhpautos)
Jan 28, 2010 at 7:42 PM
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TOOOMANYTOYS
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Have you tried replacing the hose from the coolant tank to the radiator. If it has internal blockage the pressure will blow through, but the vacuum may not be strong enough to pull it out. If that doesnt work I would suggest doing a block check to make sure there are no internal engine leaks.
Jan 28, 2010 at 7:47 PM
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