Mercury Grand Marquis Problems

Coolant Leak and/or Engine Overheating Due to Cracked Intake Manifold on Mercury Grand Marquis

Problem Description and Possible Solution

The 1996-2001 Mercury Grand Marquis with a 100% plastic intake manifold  is known for engine overheating, even with normal use, and a coolant leak from the front of the manifold. This will often trigger the check engine light and low engine coolant warning light.

The engine coolant leak is from a factory defect, which causes cracking on the front coolant passage of the intake manifold. In a very short time, this leak will lead to engine overheating issues, especially while the vehicle is idling.   

Between 1999 and 2001, Ford released an updated version of this engine, known as the 'PI' version with a metal coolant passage on the front of the intake manifold, to prevent future issues.

There is no factory authorized repair for the intake manifold, and replacement is required to correct the engine coolant leak and overheating issues.


(216 people reported this problem)

Mercury Grand Marquis Vehicles With This Problem

RepairPal Verified
Average mileage: 121,865 (10,700–308,000)
14 model years affected: 1991, 1996, 1997, 1998, more1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
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Viewing 1-20 of 119 comments
crack in the intake manifold...saw a recall on it for the plastic one to be replaced with the new aluminum, but my luck it does not apply to me because my car is to old. My mechanic is charging me 950 for the fix and said he would keep the information he found on line for this. I think Ford being a reputible company and Michigan based should step up and support all who have this problem no matter when it occurs
Heater box to intake manifold heater hose nipple stripped out at manifold. Lose about 1 gallon of antifreeze every 3 weeks. My mechanic says this is a common problem. Ford should be embarrassed and replace all for free. The engineer that designed the manifold and the manager that approved the design should own one of these cars for the rest of their lives.
Plastic manifold cracked at the thermostat. No way to fix so no option but to replace. Dealer said it would cost $1,260 to replace (includes $400+ for the part). I bought the part on-line for $216 and did it myself. Took several hours but was not terribly difficult. Just a lot of stuff to take off, so mark hoses and wires well.
Intake manifold cracked... gonna cost a bundle to replace. It would be nice if they weren't made out of plastic! Just doesn't make a whole lot of sence to me.
I purchased my Grand Marquis LSE new in 2003. As you can see from the mileage I do not drive the car a lot of miles per year. I maintain the car as required including replacing belts and hoses as required. The intake manifold developed a crack and had to be replaced. The cost was over $1000.It's a shame that an automobile that cost over $32000 at the time is manufactured with plastic parts that don't hold up. So much for Fords quality. I can see that I'm not the only one who has had this problem. One would think that Ford would stand behind their product. Although most of the reports that show this problem have a lot more miles on them than I do this part should not fail under normal driving conditions.
had my merc for awhile now and suddenly i smelled something and then saw smoke coming from under the hood, i pulled over and saw coolent everywhere took it in and found out i have a small crack behind my alternator on my intake manifold...did lots of research and come to find out im not the only one with this problem THANKS FORD.. for a new manifold online for $210 and now im going to attempt to replace it myself after finding out having a professional do what i can figure out will be 4 to 500 just for labor so wish me luck and again THANKS FORD!!
If there wasn't a recall, WHY CAN'T WE MAKE A CLASS ACTION LAW SUIT????
a 2004 Grand Marquis with this problem.
Just bought the car from an elderly gentleman who was the original owner. Looked and drove great untill I got it on the freeway and it went up in smoke... or should I say steam. Manifold cracked in the exact spot and cost me $1000 to fix. This will be my car for a long time, I hope.
This 1999 Grand Marquis LS was purchased new; carefully run in the first 1,500 miles. One owner driven these miles and serviced regularly by authorized dealer only. Car does ot burn any engine oil - careful run in the first 1500 miles. Check oil, water regularly and began to notice overflow coolant tank needed topping up every two or 3 months. Car runs very smoothly till i found the puddle of yellowish fluid on the garage floor after a 45 min. drive. Soaked up fluid on paper and took it to Mercury dealership who determined the cracked manifold that needed to be replaced. Parts and labor totalled to $1300. I always request to save old parts to see how the parts wear or damaged. The new manifold was Made in China. (so are other Ford parts like Brake Rotors etc.) Said to be using thicker plastic, alum parts and should not crack too easily. However, i see GM's with 75,000 miles or less are having crack manifold problems.
Personal Observation: The manifold is made of plastic composite wrapped over some alum. ducting or piping. Elementary physics taught us that plastic, composites, aluminium expands and contracts at different temperatures.... this design is so warped to have plastic wrapping over the intake manifold, is a buildt in disaster waiting to happen.... makes one wonder where these Mercury Ford engineers who designed the manifold came from???
Ford should be more responsible for their poorly designed products.
Parked in garage after a 45 miles drive. Found puddle of yellowish engine oil like fluid on floor. Car never overheat and no problem with transmission. Engine oil, power steering, brake and auto trans fluid all check out fine except coolant low and disappeared from overflow tank. Dealership identified the coolant leak caused by cracked intake manifold. Cost $1300 to replace.
Out of nowhere car began overheating without indicator light coming on; Went to firestone they misdiagnosed it with thermostat and O-ring and just when I thought my problem was solved leak began to get worse. So out of concern took it to ford and they wanted to charge 2900 to fix issue along with a other list of items they recommend. found part online for 250 and paid side mechanic 400 to put it on. I honestly could not believe that they part would fail like that and come to find it being a huge issue its no wonder police agencies dumped the crown vic and re-up inventories with chargers and caprice's in my area. Maybe I should do the same if another issue like this happens. It's things like this that makes dedicated owners of ford products to jump ship. There is no loyalty anymore with these companies just cheap parts and poor quality.
I have an 07 crown vic police model...everyone i know who has a crown vic or grand marquise has changed the intake needs to recall this part...$250 for part....not to mention how much labor would be if i didnt do it myself...