The 1991 Eagle Summit is a rebadged Mitsubishi Mirage/Colt built on the Mitsubishi platform. These are generally scrappy econoboxes, but age has not been kind—expect head gasket failures, transmission cooling issues, and typical late-80s Japanese rubber deterioration.
Cylinder Head Gasket Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: white smoke from exhaust, coolant consumption without visible leaks, milky oil on dipstick or cap, overheating under load, rough idle when cold
Fix: Head gasket job on these requires head removal, resurfacing (warpage is typical), new head bolts, and timing belt replacement while you're in there. Budget 8-12 hours labor depending on engine size. The 1.5L is cramped but simpler; 1.8L and 2.4L add complexity. Always pressure-test the block and check for cracks.
Estimated cost: $1,200-2,200
Automatic Transmission Oil Cooler Line Leaks and Cooler Failure
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: transmission fluid pooling under car, burnt ATF smell, slipping or delayed engagement after warm-up, pink fluid mixed with coolant in radiator
Fix: The factory cooler lines rust through at the fittings, and the internal radiator cooler can fail, cross-contaminating coolant and ATF (which kills the transmission). Replace lines, external cooler, flush both systems, and pray the transmission survived. If contaminated, rebuild or replace transmission. Lines and cooler alone: 2-3 hours. With transmission damage, add 10-15 hours for a rebuild.
Estimated cost: $300-800 for lines/cooler; $1,500-2,800 if transmission is damaged
Harmonic Balancer Deterioration
Occasional · medium severityTypical onset: 100,000-150,000 mi
Symptoms: severe vibration at idle or under acceleration, visible wobble of crank pulley, rubber ring separation from hub, serpentine belt shredding or coming off, rough running that feels engine-related
Fix: The rubber isolator in the harmonic balancer deteriorates and delaminates, causing damaging vibrations. Replacement requires crank bolt removal (impact required, often seized), and timing marks must be observed. 2-3 hours labor. Check for crank snout damage during removal—scoring means more work.
Estimated cost: $250-500
Clutch Master and Slave Cylinder Failures (Manual Transmission)
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: clutch pedal sinks to floor and stays, spongy or inconsistent pedal feel, difficulty shifting into gear, fluid leak at firewall or bellhousing, grinding when attempting to shift
Fix: The hydraulic clutch system uses aging rubber seals that fail internally. Master cylinder is accessible (1.5 hours), but slave cylinder requires transmission removal on many models (add 4-6 hours). Replace both together to avoid doing the job twice. Bleed thoroughly—air pockets cause persistent problems.
Estimated cost: $400-900 depending on slave cylinder access
Timing Belt and Water Pump Failure
Occasional · high severityTypical onset: 60,000-90,000 mi (or unknown history)
Symptoms: sudden no-start with cranking but no compression, ticking or slapping noise from timing cover before failure, coolant leak from water pump weep hole, engine overheating due to pump failure
Fix: These are interference engines—timing belt failure means bent valves and possible piston damage. If the belt hasn't been done or history is unknown, do it immediately with water pump, tensioner, and seals. 4-6 hours labor. If it already failed, add valve job or head work: 10-15 hours total.
Estimated cost: $400-700 preventive; $1,500-2,500 after failure
Fuel System Corrosion and Filter Clogging
Occasional · medium severitySymptoms: hard starting after sitting, loss of power under load, sputtering or hesitation at highway speeds, fuel smell near tank, check engine light with lean codes
Fix: Fuel tanks rust internally on neglected examples, and old fuel breaks down, clogging filters and injectors. In-tank pump screens clog first. Replace fuel filter (under car, 0.5 hours), inspect lines for rust perforation, drop tank if contamination is suspected (add 3-4 hours). Injector cleaning or replacement may be needed.
Estimated cost: $100-250 for filter/lines; $600-1,200 if tank/pump involved
Transmission Mounts Collapsing
Common · low severityTypical onset: 80,000-120,000 mi
Symptoms: clunking when shifting from reverse to drive, excessive engine movement visible when revving in park, vibration through shifter or floor, rattling over bumps
Fix: Rubber transmission mounts age-harden and tear, allowing excessive drivetrain movement. Front and rear mounts commonly fail together. Replacement is straightforward with a jack supporting the transmission. 1.5-2 hours labor for both.
Estimated cost: $200-400
Only buy if you find a cherished, documented example under 100k miles and can wrench yourself—repair costs will quickly exceed the car's value at a shop.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.