A common issue we're seeing is that the coolant cap design for the recovery tank was faulty from the factory. The cap will fail without warning, causing significant coolant loss.
ALL Ford dealerships and vendors were instructed to return the obsolete design so they could be destroyed, so the caps in the parts chain are all the new design.
: At some point Ford started to use the new cap design on the cars coming off the line. I would hazard a guess that 2013 on would have the new cap. Doesn't hurt to check using the pictures below. Also, your older car may have had it replaced by the previous owner.
This was the old cap design on my 2003 (yours may look different)
This is the new cap design (standard across all models)
Here's a pic to help further determine if you have the bad cap (credit to user Chartmaker)
The part number for this Motorcraft part is RS-527.
It fits these Ford models and years:
FORD CROWN VICTORIA(1992 - 2011)
FORD E-150(1995 - 2014)
FORD E-250(1995 - 2014)
FORD E-350(1995 - 2014)
FORD E-450(2000 - 2014)
FORD E-550(2002 - 2003)
FORD EDGE(2007 - 2014)
FORD EXCURSION(2000 - 2005)
FORD EXPEDITION(1997 - 2008)
FORD EXPLORER(2002 - 2014)
FORD F-150(1997 - 2014)
FORD F-150 HERITAGE (2004)
FORD F-250(1997 - 1999)
FORD F-250 SUPER DUTY(1999 - 2014)
FORD F-350 (1997)
FORD F-350 SUPER DUTY(1999 - 2014)
FORD F-450 SUPER DUTY(1999 - 2014)
FORD F-550 SUPER DUTY(1999 - 2014)
FORD FIVE HUNDRED(2005 - 2007)
FORD FLEX(2009 - 2014)
FORD FREESTAR(2004 - 2007)
FORD FREESTYLE(2005 - 2007)
FORD FUSION(2006 - 2012)
FORD GT(2005 - 2006)
FORD MUSTANG(1996 - 2014)
FORD POLICE INTERCEPTOR SEDAN(2013 - 2014)
FORD POLICE INTERCEPTOR UTILITY(2013 - 2014)
FORD RANGER(2001 - 2011)
FORD TAURUS(1996 - 2014)
FORD TAURUS X(2008 - 2009)
FORD THUNDERBIRD(1994 - 2005)
FORD WINDSTAR(1999 - 2003)
LINCOLN AVIATOR(2003 - 2005)
LINCOLN BLACKWOOD (2002)
LINCOLN CONTINENTAL(1995 - 2002)
LINCOLN LS(2000 - 2006)
LINCOLN MARK LT(2006 - 2008)
LINCOLN MARK VIII(1993 - 1998)
LINCOLN MKS(2009 - 2014)
LINCOLN MKT(2010 - 2014)
LINCOLN MKX(2007 - 2013)
LINCOLN MKZ(2007 - 2012)
LINCOLN NAVIGATOR(1998 - 2013)
LINCOLN TOWN CAR(1992 - 2011)
LINCOLN ZEPHYR (2006)
MERCURY COUGAR(1994 - 1997)
MERCURY GRAND MARQUIS(1992 - 2011)
MERCURY MILAN(2006 - 2011)
MERCURY MONTEGO(2005 - 2007)
MERCURY MONTEREY(2004 - 2007)
MERCURY MOUNTAINEER(2002 - 2005)
MERCURY SABLE(1996 - 2009)
If your car is on this list, and the cap has not been replaced (or was replaced with an aftermarket unit), I highly recommend you replace the cap. Go with the Motorcraft (aka Ford) part on this one, as the aftermarkets are based on the flawed original design.
There are two easy ways to get the cap.
1. Drive to your local Ford dealer. Ask for the cap. They will likely have it, since it's used on so many models, or they might have to order it. I did this, and it cost me about $13 with tax. Price will vary slightly for you based on tax.
2. Visit RockAuto Parts Catalog
and order the cap. Use the latest discount code found on this forum at this link: RockAuto - Taurus Car Club of America : Ford Taurus Forum
The code goes in the "How Did You Hear About Us" box at checkout. The part at Rock Auto was $6.09 at the time I made this post, and with shipping to my house and with the discount (only .30 cents since it's a 5% code) it was $8.23 in total.
This post is for informative purposes only, and should your car detonate, mutate into a swamp-monster, or suffer a problem I am not liable.
Prices current as of December 2013.