Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 1998 Mercury Grand Marquis owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 1998 Mercury Grand Marquis. While driving various speeds, the engine misfired and hesitated to respond. The vehicle was taken to an independent mechanic who diagnosed that the plastic intake manifold was cracked, which caused anti freeze to leak out and damage the engine coils. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was 80,000.
I observed a coolant leak around the thermostat. I found the plastic intake manifold to be cracked around the thermostat and leaking coolant. I made contact with Mercury and found that there had been a recall on the plastic intake manifold in which they would have replaced the part at no charge during the safety recall campaign. I was not made aware of the safety recall and have owned the vehicle since 04/17/02 when I purchased the vehicle used from a Mercury dealership. The dealership would no longer honor this recall although there are still thousands upon thousands of these engines still on the road. The all plastic manifold was replaced with an intake manifold with an aluminum crossover channel for the coolant. I was forced to replace this defective part out-of-pocket at a cost of $800. It would have been more had I not been friends with the mechanic. …
Tl contact owns a 1998 Mercury Grand Marquis. After driving 65 MPH, the contact noticed fuel leaking from the vehicle. She stated that the intake manifold cracked and she took the vehicle to the Ford dealer. The dealer informed her that there was a recall on her vehicle, but they would not honor it because it was only good for seven years. She took the vehicle to an independent dealer and paid $850 for the repair. The VIN and engine size were unknown. The current and failure mileages were 113,000. Updated 12/12/2007 the consumer stated the intake manifold was a defect that Ford refused to pay for the repairs. The consumer stated would like to be reimbursed for repairs. Updated 12/12/07
Vehicle started to buck and when I pulled my vehicle over I lifted the hood. I found anti-freeze flowing on the top of my engine. I had it towed to my local garage & they told me that the intake manifold is cracked. I did some research and found out there's a recall on this part. When I called my local Ford dealer, they told me there is a recall on this part, but it's only for police and fleet vehicles only. Now that this was said to me, I was told by my garage it would cost me $1000 to fix. Something I don't have. Ford was not very cooperative about my situation and I'm very disappointed.
Dt: the caller said her car burned up in 2000. Now she is finding out about the investigation into the cruise control fires. She believes that the car should be included. At the time she was told to call the insurance company, they said to call manufacturer, and she was getting the run around. She saw on cnn and the newspaper about the current problem they are having and wanted someone to help her. There is a fire report. The vehicle fire was contained to the engine compartment and dash area.
While driving vehicle stalled. Consumer used a starter battery kit to restart the vehicle or contacted aaa to have the vehicle towed. The aaa representative indicated that the stalling May be due to engine motor failure. Dealership and sears retail store performed a diagnostic test, but no failure code was found. Also , the battery and air bag warning light came on. This failure almost caused rear end collision. Owner is an ex philadelphia Eagle football player named curtis bunch-black.
Tl* the contact owns a 1998 Mercury Grand Marquis. The contact stated that the vehicle would overheat abnormally. The vehicle was taken to a local repair shop where the radiator was flushed but to no avail. The contact later inspected the vehicle and discovered that the intake manifold was fractured. The contact believed that the failure was caused because the intake manifold was designed using plastic. The vehicle was not repaired. The VIN was unavailable. The failure and current mileage was 64,950.
Tl contact owns a 1998 Mercury Grand Marquis. Whenever the contact turned the vehicle on he noticed that the check engine light would appear on the dashboard. While examining the engine he also noticed that anti-freeze was leaking onto the engine. The vehicle has not been diagnosed by the dealer. The failure mileage was 100,000.
The plastic intake manifold in my 1998 Grand Marquis has cracked resulting in engine coolant fluid leak and engine failure. It is being repaired today. The car has approximately 87,000 miles. I understand that this occurs because of the material used for the intake manifold. The car is in otherwise very good condition.
Plastic intake manifold cracked and leaking coolant around thermostat area that squirts out under driving conditions and pools around fuel injection and contaminates electronics and serpentine belt and pulleys. Could leak to overheating and engine failure . Poor driving condition.
NHTSA investigations
Spark plug ejection from cylinder head
On September 6, 2005, odi received a petition requesting that the agency investigate allegations of engine spark plug ejection in certain model year 1997 through 2004 Ford vehicles with triton v-8 and v-10 engines.odi received a total of 474 non-duplicative complaints on the subject vehicles where the complainant, or the dealer repairing the vehicle, reported that a spark plug detached from the cylinder and/or…
Engine complaints in other Grand Marquis years
Frequently asked questions
How common are engine problems on the 1998 Mercury Grand Marquis?
NHTSA has 29 complaints about the engine & cooling of the 1998 Mercury Grand Marquis, 20% of the model year's 143 complaints. The component named most often is engine › gasoline (7 mentions).
Is there a recall for 1998 Mercury Grand Marquis engine problems?
No. NHTSA lists no engine & cooling recall for the 1998 Mercury Grand Marquis, though it has 5 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 1998 Mercury Grand Marquis engine problems start?
Half of the complaints with a recorded mileage happened before about 102,000 miles.
Is it dangerous?
Owners linked 0 crashes, 2 fires and 1 injury to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.