1998 Ford Expedition Problems

What owners report

Owners of this model year most often describe spark plugs blowing out of the cylinder head, sometimes with a loud bang and a sudden loss of power, and a second large group reports under-hood smoke or fires traced by owners and mechanics to the speed control switch and nearby wiring. Rear suspension arms rusting through and brake lines rusting out are also reported at higher mileages. Most complaints arrive well past 80,000 miles on a vehicle that is now decades old, so condition and prior maintenance matter more than any single failure.

1. 1
   Engine cooling

   Spark plug blown out of cylinder head

   • 129 complaints (15%)
   • median 110,500 mi at 8.2 yrs old (98 state mileage)
   • 4 mention a crash, fire or injury
   • owner-quoted repair $2,050 (median of 30 quotes)
   • filed 1999–2019

   Owners describe a loud pop or bang, then rough running, misfire and lost power, and on inspection a spark plug has been ejected from the cylinder head with the threads stripped. Some report it happening more than once on different cylinders. According to the complaints, dealers typically recommended replacing the cylinder head or the whole engine, and owners say the repair was expensive; a service bulletin covers a spark plug thread repair procedure for these engines and notes it is not covered by the new vehicle warranty. Reported mostly between roughly 50,000 and 160,000 miles, often during acceleration or highway driving.

   1 related service bulletin

   What to check: Ask whether any plug thread repair or head replacement has been done, and have a mechanic check plug torque and look for signs of thread repair. Owners sometimes report a fuel smell after an ejection, so check for that too.

   2 excerpts from owner complaints in NHTSA records

   “My 1998 Ford Expedition blew out a spark plug on the highway while I had my baby daughter in the truck. I lost power and had to swerve into the slow lane almost causing multiple accidents . This is the 2nd time this has happened and still no recall.”

   NHTSA complaint #10220757, filed 2008-03, 110,000 miles

   “Our 1998 Ford Expedition with the 5.4 v8 triton engine had another spark plug blow out of the cylinder head. The last time this happened was about 3 years ago, it was the #3 cylinder plug then and last week it was the #6 cylinder plug, I searched the internet concerning this problem and found hundreds if not more of the same issues, and no one is making Ford do anything about this, just thought my voice in this matter might help. Please if there was ever an instance of a recall this is surely one. …”

   NHTSA complaint #10413768, filed 2011-07, 144,000 miles
2. 2
   Vehicle speed control

   Under-hood smoke and fires at speed control switch

   • 114 complaints (14%)
   • median 120,000 mi at 8.7 yrs old (76 state mileage)
   • 74 mention a crash, fire or injury
   • owner-quoted repair $2,000 (median of 7 quotes)
   • filed 1999–2019

   Many complaints describe smoke or flames from under the hood while the vehicle was parked, sometimes after sitting for a short time, and some say the vehicle was destroyed. Several owners state that inspection or the fire department traced the origin to the speed control deactivation switch or the wiring near it; in some cases the brake pressure fuse had blown and the vehicle could not be shifted out of park. A recall covering the speed control deactivation switch overheating, smoking or burning exists for certain vehicles. Reported from roughly 60,000 to 200,000 miles, typically while parked with the engine off.

   Recall 05V388000

   What to check: Ask whether the speed control deactivation switch recall work was completed and whether the switch or its jumper harness has been replaced; a visual check of the switch at the master cylinder for scorching or fluid residue is quick.

   2 excerpts from owner complaints in NHTSA records

   “My 98 Expedition was parked in my garage when my son came home and opened the garage a saw smoke coming out. I had been home about 80 mins. The smoke was coming from under the hood of my exp. I quickly started the vehicle to get it out of the garage area, but it would not go into reverse - the brake pressure fuse had blown due to the wire fire, so the car was stuck in park. Luckily the fire went out on it's own. …”

   NHTSA complaint #10131578, filed 2005-08, 118,000 miles

   “I have a 1998 Ford Expedition, and the cruise control stopped working, the anti-lock brakes stopped working, the brake lights stopped working, and I could not put the car in gear. I looked at the fuse box and found a fuse blown. When I replaced the fuse, the engine compartment in the car started smoking profusely. I pulled the fuse out right away, and had someone watch as I put it back in. The smoking started again, and it was coming from some type of brake switch on the front of the master cylinder. …”

   NHTSA complaint #10114777, filed 2005-03, 148,515 miles
3. 3
   Electrical system

   Interior lights stay on and water leaks into fuse box

   Mentioned in 7 of 60 sampled complaints

   Owners report interior lights that stay on after the doors are closed or flash while driving, and some link it to a door ajar switch. Others describe water from the windshield leaking onto the fuse box and control modules, producing symptoms such as windows, wipers, warning lights and the radio switching on and off by themselves, and a battery that keeps going dead. Complaints mention a body control module being replaced and anti-theft reprogramming at owner expense. Reported from about 50,000 to 180,000 miles, often after rain.

   What to check: After a rain or a wash, check the passenger footwell and fuse box area for dampness or corrosion, and confirm the dome lights go out with all doors shut.

   2 excerpts from owner complaints in NHTSA records

   “Our 1998 Expedition only has 93,000 miles and it is posing electrical problems, the mechanic has told us it needs a new gem module. I have read at least 50 complaints about fords windshield leaking and causing same symptoms. Why would Ford do a recall. Or maybe they have. Can you tell me if they have. This could cause a fire which could cause a sever accident. All the complaints are very similar so it is a manufactured defect.”

   NHTSA complaint #10318418, filed 2010-03, 93,000 miles

   “Went to store, came out battery dead, car wouldn't start. Had not left lights or any accessories on. Got a jump, drove to auto parts store. They checked alternator and battery and said battery dead, needed an overnight charge. Let them charge battery, put back in car, horn started blowing and would not stop despite my using both the key and key fob. Horn blew for 5 hours before I found out how to disconnect from google. Got horn to stop, and car wouldn't start. …”

   NHTSA complaint #10852469, filed 2016-03, 203,538 miles
4. 4
   Suspension

   Rear suspension arms rusted through

   • 86 complaints (10%)
   • median 117,831 mi at 12.8 yrs old (33 state mileage)
   • 3 mention a crash, fire or injury
   • filed 1998–2017

   Complaints describe the rear trailing arms or support arms rusting completely through and breaking, which lets the rear axle shift and in some cases the driveshaft come loose. Owners report a lean to one side, a snap or bang at low speed, and the vehicle becoming immovable. Some also mention the rear air suspension failing or the lift system dropping without a warning light. Mostly reported from about 130,000 to 180,000 miles and beyond, on vehicles in rust-prone areas.

   1 related service bulletin

   What to check: Have the rear trailing arms and axle mounts inspected on a lift for rust-through or heavy scale, especially on vehicles from salt-belt states; also confirm the rear air suspension holds height overnight.

   2 excerpts from owner complaints in NHTSA records

   “I had a catastrophic failure of the rear suspension arms on my 1998 Ford Expedition. I was traveling at a slow speed when the arm snapped without warning. Had this suspension arm broken at highway speed, the result would have been a life threatening wreck. The rear end rolled up causing the vehicle to be immovable , requiring a tow for repairs. An inspection revealed, the upper support arm for rear the suspension rusted completely through, causing the arm to break. …”

   NHTSA complaint #10342406, filed 2010-07, 180,000 miles

   “It has come to my attention that the trailing arms on the rear axle are failing on the early model Ford expeditions. Upon inspection of my vehicle, I see where the failure is going to occur. The trailing arms are rotting out and will allow for the rear axle to twist out of place causing the drive shaft to become dislodged and become a large run away component. These components on my vehicle will have to be replaced prior to this vehicle being placed back in service as this is a large safety concern. …”

   NHTSA complaint #10400581, filed 2011-05, 160,000 miles

Buying note. This is an old vehicle with well-documented patterns, so a pre-purchase inspection focused on the rear suspension arms, brake lines, spark plug threads and the speed control switch is worth the cost. Confirm in writing whether the speed control recall was completed, and budget for repairs rather than relying on the history alone.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.