1996 Mercury Sable losing antifreeze from overflo tank

LONNIE PHILLIPS

MEMBER
1996 MERCURY SABLE
6 CYL
2WD
AUTOMATIC
20,000 MILES

The engine only has 100 miles since rebuild. It does not overheat. Water pump is good, new thermostat, new overflo tank & cap, and no external leaks. Car runs great. No oil in water or compression leak. It just keeps blowing the cap off and losing the antifreeze even though the engine is at normal operating temp. Any advice you can give would be greatly appreciated! I am donating what I can at this time as I am on a small fixed income and cannot afford to have mechanic work on this car. It is old, but all I have. Thanks guys!

Saturday, October 9th, 2010 AT 2:26 PM

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

The pressure cap should be releasing pressure if it gets to typically around 16 psi. For it to be blowing off, it either has to be a damaged cap, a damaged reservoir, or a mismatch between the two. How does it feel going on? From the illustration, it is a threaded type cap. Can it be tightened to the point that it overruns. If nothing looks visibly at fault, like the cap or a damaged rexervoir, I would have the cap pressure checked. It would be worth it to have the parts checked for proper application as well.

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Saturday, October 9th, 2010 AT 10:49 PM