Troubleshooting Mitsubishi GS16-GS25 faults
Is your Mitsubishi GS16-GS25 not running as it should? The cause is often simple and easy to fix yourself. This troubleshooting guide combines the official fault tables from the manual with the problems owners encounter most often in practice — for the GS16, GS18, GS20, GS21, GS23 and GS25.
Suitable for the entire series: Mitsubishi GS16, GS18, GS20, GS21, GS21S, GS23, GS25 and GS25S.
Mitsubishi GS16-GS25 won't start or starts hard
| Symptom | Probable cause | Solution |
|---|---|---|
| Key turned, starter motor doesn't turn | Clutch not fully depressed | Fully depress clutch pedal (safety start) |
| Starter motor doesn't turn | Battery flat or terminal loose/corroded | Charge/replace battery; clean terminals, tighten, grease |
| Starter motor doesn't turn | Blown fuse | Check wiring, replace fuse |
| Starter motor turns, engine won't start | No fuel or fuel filter clogged | Refuel; clean/replace filter |
| Starter motor turns, engine won't start | Air in the fuel system | Bleed the fuel system |
From the field: with grey imports, worn glow plugs and a weak battery are the most reported cold-start complaints. Check the glow plugs (for reference, verify by serial number whether they fit your model) before looking further.
Mitsubishi GS16-GS25 power loss or engine cutting out
| Symptom | Probable cause | Solution |
|---|---|---|
| Engine runs unevenly | Air in fuel, water/dirt in filter, fuel leak | Bleed, clean/replace filter, check connections |
| Engine suddenly cuts out | Fuel shortage or fuse H blown | Refuel + bleed; check/replace fuse |
| Power loss | Air filter or fuel filter clogged | Clean air filter, check fuel system |
| Black exhaust smoke | Air filter clogged or poor quality fuel | Clean element, use correct fuel |
| White exhaust smoke (not right after start) | Too much engine oil | Correct the level to the proper mark |
| Oil pressure lamp lights during operation | Oil low, oil too thin, or oil filter clogged | Top up, use correct oil, replace oil filter |
| Charge lamp lights during operation | Fan belt loose or broken | Tension or replace belt |
Mitsubishi GS16-GS25 overheating
A rising coolant temperature is almost always caused by a clogged radiator (screen), insufficient coolant, a loose or broken fan belt, or too low an engine oil level. Clean the radiator screen (especially after dusty work), top up the coolant, check belt tension (10-13 mm deflection) and the oil level. If the engine keeps overheating, have the thermostat and water pump checked.
Mitsubishi GS16-GS25 brake and clutch complaints
| Symptom | Probable cause | Solution |
|---|---|---|
| Clutch slips | Pedal play incorrect or plate worn | Adjust play (20-30 mm); replace worn plate |
| Clutch doesn't disengage | Pedal play incorrect or plate stuck | Adjust play; if plate is stuck: visit a workshop |
| Brake weak or pulling to one side | Pedal play too large, lining worn, left/right unequal | Adjust play (35-45 mm equal); have lining replaced |
| Brake pedal returns poorly | Return spring broken or lubrication dry | Replace spring, lubricate pivot points |
Mitsubishi GS16-GS25 steering and hydraulic complaints
| Symptom | Probable cause | Solution |
|---|---|---|
| Steering wheel turns freely / no steering response | Transmission oil low, line leaking or pump faulty | Top up oil to the correct level; have line/pump checked |
| Steering heavy or pulling | Tyre pressure unequal, rod-end play, cold/thick oil, incorrect toe-in | Equalise pressure, warm up, have toe-in corrected |
| Front wheel shakes (excessive steering play) | Mounting loose, rod-end play, toe-in, or air in steering cylinder | Tighten, check oil level and bleed |
| Lift slow or hydraulics noisy | Oil low, not warmed up, or hydraulic filter clogged | Top up, warm up, replace hydraulic filter |
From the field: on the GS series, the hydraulic pump is occasionally mentioned as a source of faults, and parts for it are harder to find. So always start with the simple things — oil level, clogged filter, bleeding — before thinking about expensive parts. The earth points and battery terminals are also a classic source of erratic electrical faults; fifteen minutes of cleaning and greasing solves surprisingly much.
Product tip. Many faults can be solved with basic parts: start with a fresh filter set (SKU-100164) and, for cold-start problems, the glow plugs (SKU-55808). If the engine keeps overheating, check the water pump (SKU-323), the thermostat (SKU-45004) and the fan belt (SKU-1240031).
