The John Deere 4020 diesel takes 8 quarts on early models and 12 quarts on most later models (with filter).
John Deere 4020 Oil Capacity and Type
| Early Diesel Oil Capacity | 8 qt / 7.6 L (with filter) |
| Later Diesel Oil Capacity | 12 qt / 11.4 L (with filter) |
| Gasoline Engine Oil Capacity | Approx. 8 qt / 7.6 L |
| Recommended Oil Type | 15W-40 diesel engine oil (modern standard) |
| Alternative Oil | SAE 30 (commonly used in original specs) |
| Engine | John Deere 6-cylinder liquid-cooled |
| Diesel Displacement | 404 ci / 6.6 L |
How Much Oil Does a John Deere 4020 Take?
The John Deere 4020 does not have a single fixed oil capacity across all models.
Early diesel tractors take approximately 8 quarts, while most later diesel models take around 12 quarts. This change occurred around the 1969 model year (near serial number 201000).
Oil capacity figures assume the oil filter is replaced. Always fill slightly under, run the engine, let it settle, then check the dipstick and top up.
Quick Specs Overview
8 qtEarly Diesel
12 qtLater Diesel
24 qtCoolant
34 galFuel Tank
Oil Capacity Comparison
Best Oil to Use
- 15W-40 diesel engine oil is the standard modern choice
- SAE 30 straight oil was commonly used when these tractors were new
- Use heavier oil if the engine is worn or used in hot conditions
- Always choose oil rated for diesel engines
Oil Change Intervals
| Typical Modern Practice | 100 to 150 hours |
| Light Use | Up to 200 hours |
| Heavy Work / Old Engine | Closer to 100 hours |
| Oil Filter | Replace with every oil change |
Common Mistakes
- Assuming all John Deere 4020 tractors take 12 quarts
- Confusing diesel, gasoline, and LP-gas versions
- Overfilling by not checking the dipstick after running
- Skipping the oil filter when changing oil
- Using oil not suitable for diesel engines
Other John Deere 4020 Fluid Capacities
| Engine Oil – Early Diesel | 8 qt / 7.6 L |
| Engine Oil – Later Diesel | 12 qt / 11.4 L |
| Coolant Capacity | 24 qt / 22.7 L |
| Fuel Tank (Gas/Diesel) | 34 gal / 128.7 L |
| LP-Gas Tank | 45 gal / 170.3 L |
| Hydraulic System – Syncro | 10 gal / 37.9 L |
| Hydraulic System – Power Shift | 12 gal / 45.4 L |
John Deere 4020 Engine Specs
| Production Years | 1964 to 1972 |
| Engine Type | 6-cylinder diesel (or gas / LP variants) |
| Displacement | 404 ci / 6.6 L |
| Rated RPM | 2200 rpm |
| Cooling System | Liquid-cooled |
Summary
The John Deere 4020 diesel takes 8 quarts on early models and 12 quarts on most later models. Because multiple engine versions exist, the correct approach is simple: fill slightly under spec, run the engine, let it settle, then verify using the dipstick.