Regular engine oil and filter changes are among the most important maintenance jobs on any tractor, excavator, loader or diesel engine. Correct oil protects bearings, pistons, turbochargers, camshafts and valve gear while carrying heat, soot and contamination away from critical surfaces.

Before You Start

• Park the machine on level ground
• Lower all implements safely
• Apply the parking brake
• Stop the engine and remove the key
• Allow hot components to cool enough to work safely
• Have the correct oil quantity and filter ready

1. Identify the Correct Oil

Use the operator or workshop manual to confirm:

• SAE viscosity grade
• API or ACEA specification
• Manufacturer approval
• Oil capacity
• Service interval

Common SAE Grades

Grade	General use
10W-30	Common multi-grade oil for mixed temperatures.
10W-40	Common on many diesel engines, including turbocharged applications.
15W-40	Very common heavy-duty diesel oil for older and many mid-generation engines.
5W-30 / 5W-40	Often used where better cold-start performance or specific modern approvals are required.

This is only a general guide. Always follow the machine specification.

2. Warm the Engine First

Changing oil when warm helps suspend contamination and allows the sump to drain more completely.

Do not work on oil that is hot enough to burn.

3. Remove the Drain Plug

1. Place a suitable container beneath the sump.
2. Clean around the drain plug.
3. Remove the plug carefully.
4. Allow the oil to drain fully.
5. Inspect the drain plug and sealing washer.

Check the Drain Plug

If fitted with a magnet, inspect it for metal particles. A light grey paste can be normal, but flakes, chips or larger fragments should be investigated.

4. Remove the Old Oil Filter

Depending on the engine, the filter may be:

• Spin-on type
• Cartridge type
• Replaceable element in a housing

Make sure the old rubber sealing ring comes away with a spin-on filter. A double gasket can cause a major oil leak.

5. Prepare the New Filter

Spin-On Filter

• Check the filter part number
• Lightly oil the sealing ring
• Fit by hand
• Tighten according to filter or manufacturer instructions

Do not overtighten with a filter wrench unless the specification calls for it.

Pre-Filling the Filter

Some large vertical filters can be pre-filled with clean engine oil. On other engines, especially where contamination risk is high or filter orientation makes it impractical, dry fitting may be specified.

Follow the manufacturer procedure.

6. Refit the Drain Plug

Use a new sealing washer if specified and tighten the plug to the correct torque.

7. Refill With Fresh Oil

1. Add most of the specified quantity.
2. Wait for the oil to settle.
3. Check the dipstick.
4. Top up gradually.
5. Do not overfill.

8. Start the Engine and Check Oil Pressure

Start the engine and allow it to idle.

• Confirm oil-pressure warning light goes out
• Watch the oil-pressure gauge if fitted
• Check around the filter
• Check the drain plug for leakage

If oil pressure does not appear normally, stop the engine immediately and investigate.

9. Stop and Recheck the Level

After the engine has run briefly:

1. Stop the engine.
2. Wait several minutes.
3. Recheck the dipstick.
4. Top up if necessary.

The filter will have filled during the first start, so the final oil level may be lower than immediately after filling.

How Often Should Engine Oil Be Changed?

Intervals vary greatly. Typical service schedules may use:

• Engine hours
• Calendar time
• Whichever comes first

Machines doing short runs, heavy loading, dusty work or long periods of idling may need more frequent servicing.

Low-Hour Machines Still Need Oil Changes

A tractor that only works a few hours each year can still accumulate:

• Condensation
• Acids
• Fuel dilution
• Soot

For lightly used machines, calendar-based oil changes can be just as important as hour-based intervals.

Turbocharged Engines

Turbochargers depend on clean engine oil.

Good Practice

• Use the correct oil specification
• Do not extend service intervals excessively
• Allow oil pressure to establish after starting
• After heavy work, allow a brief cool-down period if the manufacturer recommends it

Modern Emissions Engines

Engines fitted with DPF, DOC, SCR or other emissions equipment may require low-ash oil.

Using an older high-ash diesel oil can shorten DPF life even if the viscosity appears correct.

Oil Level Too High

Overfilling can cause:

• Oil aeration
• Crankshaft windage
• Seal leakage
• Excess oil consumption
• Engine damage in severe cases

On some DPF engines, a rising oil level can also indicate diesel fuel dilution caused by interrupted regeneration cycles.

Oil Level Falling Quickly

Check for:

• External leaks
• Turbocharger leakage
• Worn piston rings
• Valve-guide wear
• Crankcase breather problems
• Incorrect oil grade

Milky Engine Oil

Milky oil can indicate water or coolant contamination.

Possible Causes

• Condensation on lightly used engines
• Head-gasket leakage
• Cracked cylinder head or block
• Oil cooler failure

Heavy contamination should be investigated before the engine is worked under load.

Diesel Fuel in Engine Oil

Fuel dilution can make oil unusually thin and may cause the level to rise.

Possible Causes

• Leaking injector
• Injection-pump seal leakage on some older engines
• Repeated failed DPF regeneration
• Excessive cold running

Oil Filter Warning Signs

• Filter distorted or swollen
• Heavy metal contamination inside filter
• Oil-pressure light slow to go out after start
• Wrong filter fitted
• Bypass valve problem

Engine Oil Service Checklist

Item	Check
Oil specification	Correct SAE grade and performance approval.
Oil quantity	Use correct capacity, then verify with dipstick.
Oil filter	Correct part number and seal.
Drain plug	Seal/washer and correct tightening torque.
Oil pressure	Warning lamp out / normal gauge reading.
Leaks	Filter, drain plug and surrounding seals.
Final level	Recheck after running and settling.

Used Oil Disposal

Used engine oil should be collected in a suitable container and taken to an authorised recycling or waste-oil facility. Do not pour oil onto the ground, into drains or into watercourses.

Related Agrimanual Manuals

Oil type, capacity, service interval, filter numbers and drain-plug torque vary by engine and machine.

• Search Agrimanual for operator manuals and service information
• Search Agrimanual engine workshop manuals
• Request a manual if your machine is not listed

Frequently Asked Questions

Should I change the oil filter every time I change the oil?

In most machinery service schedules, yes. The filter holds contamination removed from the old oil.

Can I use 15W-40 in every diesel engine?

No. It is common in many older and mid-generation diesels, but modern engines may require different viscosity and low-ash approvals.

Why does the oil level drop after the first start?

The new oil filter and internal galleries fill with oil. Stop the engine, allow the oil to settle and recheck the dipstick.

Why is my engine oil level rising?

Possible causes include fuel dilution, coolant contamination or overfilling. It should be investigated rather than simply drained back to the mark.

Can I mix different engine oils?

Mixing for emergency topping-up may be possible if specifications are compatible, but for normal servicing use the correct approved oil consistently.