1986 Mercury Grand Marquis problems & reliability
21 owner complaints filed with NHTSA for the 1986 Mercury Grand Marquis. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Electrical System → | 11 | 52% |
| Engine and Engine Cooling | 4 | 19% |
| Service Brakes, Hydraulic | 2 | 10% |
| Power Train | 1 | 5% |
| Steering | 1 | 5% |
| Structure | 1 | 5% |
| Tires | 1 | 5% |
| Vehicle Speed Control | 1 | 5% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Complaints by incident year
What owners report
“My 1986 mercury grand marquis goes forward when putting the transmission into reverse. There have been many close calls when someone who does not know my car tries to drive it (car wash people, mechanics, relatives, etc.). I believe the linkage going to my dashboard is not working correctly.*ak”
Power Train · filed Mar 18, 2004
“Ohio police report. While driving vehicle started to lose pressure,then began to smoke. Driver pulled over and vehicle engulfed into flames. Consumer stated that muffler had been replaced and a new engine was installed with only 20,000 miles. *tt”
Engine and Engine Cooling · filed Aug 28, 2002
“Vehicle vibrates on right front end when brakes are applied. When brakes are let go, feels like they are grabbing. Had stopped vehicle to check & noticed smoke from tires & then flames shot out. Had vehicle towed to mechanic & was informed that it was the electrical wiring harness. *ak”
Service Brakes, Hydraulic · filed Jun 8, 1999
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- BRAKE LINE PUNCTURES
Preliminary Evaluation PE91125 · opened Sep 11, 1991 · closed Jan 15, 1992
- FIRES
Preliminary Evaluation PE87055 · opened Sep 9, 1987 · closed Mar 10, 1988
Technical service bulletins
22 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 1986 Mercury Grand Marquis. The 10 most recent:
Information regarding transmission fluid usage charts. *slc
01157 · Service Bulletin/Repair Instructions · issued Aug 6, 2001
Some vehicles may exhibit heater core leaks. *slc
01156 · Service Bulletin/Repair Instructions · issued Aug 6, 2001
Subject regarding contamination from prior transmission concerns or excess wear may be trapped in the transmission fluid cooling system. *tt
002310 · Service Bulletin/Repair Instructions · issued Nov 13, 2000
Information regarding the new transmission cooler flusher- service tip. *mjs
0015 · Service Bulletin/Repair Instructions · issued Jan 10, 2000
Subject on a wire harness terminal repair kit available for repairing electrical wiring harnesses. *tt
99222 · Service Bulletin/Repair Instructions · issued Oct 18, 1999
Information on identifying non-approved / alternate refrigerants which could cause safety, and performance concerns if installed in ford a/c systems. *tt
99196 · Service Bulletin/Repair Instructions · issued Sep 20, 1999
Information on the new flush and fill tool available through rotunda. *tt
99152 · Service Bulletin/Repair Instructions · issued Jul 26, 1999
Ford motor company has released a new electrical grease ( f8az - 19g208-aa ) to reduce the possibility of moisture corrosion at the terminals. *yc
98246 · Service Bulletin/Repair Instructions · issued Dec 7, 1998
Information on a new transmission fluid usage chart. *yc
9888 · Service Bulletin/Repair Instructions · issued Apr 27, 1998
A new silicone gasket and sealant. *yc
9874 · Service Bulletin/Repair Instructions · issued Apr 13, 1998
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
No NHTSA recall campaigns name the 1986 Mercury Grand Marquis in our current data. Recalls may apply only to certain VIN ranges — always confirm with a VIN check.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 1986 Mercury Grand Marquis?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.