Known for their premium build, smooth Vario transmission, and high resale value, Fendt tractors are favored by professionals. But they’re not without their complexities. Some series and build periods have persistent issues that demand careful attention or should be avoided entirely.
1. Common Problems & Practical Fixes
Engine Over‑Revving & Oil Contamination (700 Series)
Driving downhill without braking first or abruptly lifting off throttle in powered gears can over-rev 700-series engines, risking piston damage and Vario transmission wear. Maintain RPM below 2,600—use the brake and exhaust brake—especially on slopes. Oil in Tier 2 models tends to carbon-load quicker; change oil every 250 hours instead of the 500-hour schedule.
Head Gasket Failures (300–600 Series, B‑Series MWM Engines)
Earlier 300/500/600 series tractors used MWM engines prone to head gasket failures due to block machining errors. Some engines even fail before 5,000 hours. Thorough inspection before purchase is essential. (UpHomely)
Transmission Errors & Vario Failures
Fendt’s Vario CVT is smooth, but can exhibit jerky behavior, slippage, early overheating, and in worst cases complete failure—especially on 900-series models logged under 5,000 hours or on early 939 builds. Check for transmission faults and service history before buying used. (Grainews)
Hydraulic System Leaks or Slow Response
Hydraulic issues include pump noise, sluggish loader or hitch operation, and spongy or unstable response. Common causes are air in the system, contaminated oil, or worn relief valves. Bleed, flush and replace filters per manual intervals to prevent pump wear. (TractorTroubleshooter)
Front Suspension Wear (800–900 Series)
Front suspension components—accumulators, bushings, bearings—tend to degrade over time. Hydraulic cylinder leaks or nitrogen loss in accumulators can result in stiff, noisy action and reduced suspension function.
Fuel Injector & Turbocharger Failures
Fuel injectors clog, wiring harnesses fail, and turbo units suffer over time. Symptoms include misfire, boost lag, loss of power or smoke. Regular filter changes and monitoring oil/turbo performance is critical.
Electrical vs ECU Glitches
Complex electronics may produce error codes, erratic lighting, or unexpected shutdowns. Issues often stem from sensor failures, harness corrosion, or firmware instability, especially on 800/900 series machines.
2. Series‑By‑Series Reliability Snapshot
🔹 700 Vario Series (Gen I–VII; 150–300 HP)
- Strengths: Smooth Vario transmission, comfortable cab, excellent efficiency, brand’s highest-selling line
- Weaknesses: Risk of over-rev damage, fan bearing wear, oil cooler leaks, exhaust manifold bolt failures, and head gasket wear in older Tier engines. Common repairs: fan bearing replacement (
6,000 h), oil cooler replacement ($240), and thermostat monitoring.
🔹 800 & 900 Vario Series (250–430+ HP)
- Strengths: Top-of-line transmissions and torque control, high aerodynamics, iD low-speed engine concept
- Weaknesses: Sensitive to dirty transmission or hydraulic fluid, brake fade, bonnet clip breakages, and early EFI or emission sensor glitches. Reviewers noted fuel filter clogs quicker than expected and broken clips around the manifolds. Brakes may need upgrades for trailered load.
🔹 300 / 500 / 600 Series (70–170 HP)
- Strengths: Balanced mid‑range power, versatile and economical for hay or row-crop applications.
- Weaknesses: Older MWM engines struggle with head gasket leaks and early engine wear. Clutch or gearbox issues may surface under hard loading.
🔹 Specialty Models: 516, Small Utility Versions
- Popular small tractors like the 516 face hydraulic lift lag, electrical faults, and occasional transmission shifting hesitancy. Ensure diagnostic codes are clean before purchase.
3. Models / Build Periods to Avoid
❌ Fendt 939 (early builds)
- Reported transmission failure before 5,000 hours and design faults in the CVT modules on early serial ranges.
❌ 700/800/900 series < 6,000 hours
- Beware of oil-blackening, failing fan bearings, cracked manifold studs, and emission system stress.
❌ Mid‑2000s 300 / 500 / 600 Series with MWM Engines
- Known head gasket failures and early engine fatigue; only buy documented rebuild history units.
❌ Early 800/900 Series With Bonnet Clasp Failures
- Bonnet clips often break and cost ~$25 each; also electrical harness faults and brake fade discovered early by users.
❌ Flagship Fendt 940MT / tracked units with second engines
- Owners on Reddit report melted engine replacements under warranty and poor resale. Avoid units with second engine history unless documented parts upgrades done. (Reddit)
4. Maintenance Best Practices
- Engine Oil: Change every 250 hours on Tier 2–4 models to avoid carbon deposition. Monitor for milky oil (sign of oil cooler leak).
- Transmission Fluid: Service Vario drive fluid per spec, keep clean to prevent jerkiness.
- Hydraulics: Flush, bleed, and replace filters (especially return filter) to avoid pressure issues.
- Suspension: Inspect accumulator nitrogen charge, front-cylinder wrist pins and bushings, and hose routing for leaks.
- Fan Bearings: Replace if there’s lateral play; failure can damage radiator/fender.
- Fuel System: Use premium diesel, change filters frequently, flush injectors if rough.
- Firmware Updates: Always work via dealer to apply upgrades to transmission, emission systems, or ECU logic.
5. Summary Table: Fendt Models to Avoid vs Reliable Picks
| Model / Series | HP Range | Known Issues | Recommendation |
|---|---|---|---|
| 700 Vario (pre‑2012 Gen I–II) | 150–300 HP | Over-rev risk, fan bearing wear, head gasket leaks | Only if service records clean |
| Fendt 939 (early builds) | ~390 HP | Early CVT/transmission failure | Avoid unless known transmission rebuilt |
| 800/900 Basic Faulty Units | 250–430+ HP | EFI sensors, bonnet clips, brake fade | Prefer post‑2015 units with warranty |
| 300/500/600 (MWM engines) | 70–170 HP | Head gasket failure, injector wear | Only buy with proven engine history |
| 700/800/900 <6,000 h | — | Fan bearing play, overheating risk | Inspect carefully, avoid if uncertified |
| 940MT tracked (2nd engine units) | High HP | Early engine failure, resale drop | Avoid unless rebuilt with warranty |
6. Owner Insights (from Reddit & Forums)
“The engine will go around 10–15k hours, but replacement costs are insane… intercooler pipes from MY 2014 blow almost weekly…and cold weather starting is a nightmare compared to Deere or Valtra.”
Another user reported the 940MT lost value dramatically after second engine replacement—$229k paid, then quoted trade-in of $125k.
✅ Final Verdict
Fendt tractors deliver advanced engineering, software-controlled smoothness, and premium resale value—but only if you’re ready to manage their complexity.
Safe Choices:
Later-generation 700 Vario (Gen4+), 900 Vario built post-2016 with low emission engines and known service history.
Caution Needed:
Early Vario 939 units, low-hour tracked models with engine replacements, and MWM-powered 300/500/600 series.
With meticulous maintenance—including oil/service timing, hydraulic fluid care, and regular firmware updates—many Fendt units reach 10,000+ hours of reliable performance. But you’ll want to choose the right model to avoid expensive surprises.
I’m David man behind Lawn Mowerly; I’ve been dealing with lawnmowers and Tractors with my father since I was a kid. I know every make and model and what each one is capable of and love helping people find the perfect equipment for their needs.