1990-2012 Mitsubishi Eclipse Problems & Issues

The 1995-1999 Eclipse GS-T and GSX use the 7-bolt 4G63 turbo engine, which is notoriously prone to 'crank walk' — excessive axial movement of the crankshaft caused by thrust bearing failure. The crankshaft literally moves fore-and-aft inside the block, eventually destroying the crank position sensor backplate and ruining the crank, block, and bearings. Root causes include factory-misadjusted clutch hydraulics leaving residual pressure on the thrust bearing, 7-bolt oil squirter design that bleeds pressure from main bearing feeds, and a metallurgically weaker crank than the earlier 6-bolt motor. Crankwalk was most prevalent in engines built in 1995, and most affected units failed at low mileage before the first timing belt service. There is no recall, and full repair requires a complete engine teardown with crank and bearing replacement.

The turbo 4G63 is an interference engine, and its narrow balance shaft belt runs directly alongside the main timing belt. When the aging balance shaft belt frays or snaps — common on neglected first- and second-generation cars — the debris gets caught in the timing belt, causing it to jump teeth or break outright. Because the pistons and valves share the same space, the result is at least eight bent valves and a cylinder head rebuild, and the owner community treats overdue belts as the single most engine-destroying maintenance lapse on these cars.

The Eclipse timing belt tensioner hydraulic damper fails, allowing the timing belt to become loose and potentially jump teeth. The water pump, driven by the timing belt, also develops bearing failure and coolant leaks. These failures are particularly common on the 4G64 and 4G69 engines.

The DOHC 4G63 (the naturally aspirated 4G63 in the 1990-1994 GS DOHC and the turbo 4G63T in the 1990-1999 turbo models) is an interference engine: if the timing belt snaps or jumps, the pistons strike the open valves, bending valves and often damaging the head and pistons. These belts were specified for replacement around 60,000 miles, and on 30-year-old cars many have been neglected or the balance-shaft belt has been ignored. On the 4G63 the timing belt drives the oil pump, which turns one balance shaft, while a separate small belt from the crankshaft drives the other balance shaft; a failed balance-shaft belt can wrap around and knock the timing belt off, causing the same catastrophic result. This is the single most important preventive-maintenance item on any 1990s Eclipse.

The 4G63's hydraulic lash adjusters (lifters) are notorious for clogging with oil varnish or bleeding down, producing the infamous DSM 'lifter tick' from the valve cover. The early-design lifters used in first-generation (1G) cars were revised twice by Mitsubishi specifically to address the noise. Forum consensus is that the tick itself rarely damages the engine — many owners drive with it for years — but it is loud, persistent, and frequently mistaken for rod knock or other serious problems.

As the 4G63/4G63T ages, the valve stem seals harden and shrink, letting oil seep down the valve guides into the combustion chamber. The signature symptom is a puff of blue smoke on startup or on a quick rev after the engine has idled for a while, plus gradual oil consumption. Turbo cars can also show smoke that is confused with turbo seal failure, so proper diagnosis matters. This is a wear/age issue rather than a design defect and is very common on high-mileage 1G and 2G cars.

Like most DSM-era cars, 1990s Eclipses in road-salt regions suffer structural corrosion of the front crossmember/subframe (which locates the lower control arms) as well as the rocker panels, strut towers, and rear subframe/trailing-arm mounts. Because the lower control arms bolt to the front crossmember, severe perforation can allow a control arm to loosen or detach, causing loss of control - the same failure mode Mitsubishi later addressed with formal crossmember-corrosion recalls on newer models (the cited bulletin/recall covers other Mitsubishi models and is referenced here as an analogous failure mode). On these 25-35 year-old cars it is a safety and roadworthiness concern rather than a warranty item, and heavily rusted examples are common in the Northeast/Midwest.

Both 1G and 2G Eclipse/Talon bodies rot in predictable places: the rear wheel arches and the lower quarter panel just ahead of the rear tires, the rocker/support area under the doors, and — most structurally serious — the front strut towers. The arch and rocker seams trap road salt and moisture between panel layers, so by the time paint bubbles appear the rust has usually perforated multiple layers from the inside out. Forum consensus treats the rear lower wheel wells and strut towers as the first places to inspect on any survivor car.

The 4-speed automatic transmission in the 3rd generation Eclipse (particularly V6 GT models) is prone to premature failure. The transmission develops harsh shifting, slipping, and eventually fails completely, often due to overheating and worn clutch packs.

NHTSA recalls 99V066001 and 00V421001 establish that damaged front lower lateral-arm ball-joint boots can admit dirt, water or moisture, leading to wear or corrosion and possible ball-joint separation. The expanded campaign remedy uses a measured wear tolerance: replace joints beyond tolerance, or clean and seal joints that remain within tolerance. Recall coverage and completion must be checked by VIN.

On AWD GSX (and Talon TSi AWD platform) cars, the transfer case output shaft seal leaks gear oil until the case runs dry, and per NHTSA recall 98V069001 'lockup of the transfer case can occur due to insufficient lubrication.' Owners have reported the wheels locking at 50-68 mph, spinning the car, with metal shavings found inside the case; NHTSA complaint records include at least one crash. Failures and re-failures are documented from roughly 55,000 to over 200,000 miles, including on cars that already received the recall repair.

The electrolytic capacitors in 1990-1994 ECUs have defective seals and leak electrolyte onto the circuit board, corroding traces and surface-mount components — 1990-1993 units are worst, and the front capacitor in 1990 ECUs is known to short and burn through the board under it, taking out the idle speed control circuit. Symptoms range from hunting/rough idle and hard starting to intermittent stalling and complete no-starts. The leaked electrolyte keeps eating the board over time, so an untouched 30-year-old ECU is assumed to need this repair.

The 4G63 uses a cam angle sensor (an optical sensor mounted in the distributor housing on the exhaust cam) to provide the crank/cam timing signal to the ECU. With age the CAS optical disc, LEDs/phototransistors, and internal bearing wear out and produce erratic or lost signals. On 1G cars the CAS is base-timing adjustable; on 2G it is fixed. Failure is a classic cause of intermittent no-start, hot-soak no-start, and random stalling on these cars, and it can be intermittent enough that tapping the sensor temporarily restores it. It is frequently misdiagnosed. (Note: crankwalk can mimic these symptoms by physically disturbing the CAS drive.)

On 1995-1999 cars the fuel pump's factory wiring is undersized and its chassis ground (at the floor crossmember under the driver's seat) corrodes with age, dropping voltage at the pump into the 10-11V range under load. The paired fuel pump/MFI relay behind the center console can also fail. The result is intermittent cranking no-starts (no pump prime), stalling, and lean stumble or fuel cut at wide-open throttle on turbo cars — a problem so common the community-standard fix is the documented 'fuel pump rewire.'