How to Check Hydraulic Fluid on a Mini Excavator: A Tutorial Guide

If you own a Chinese mini excavator, proper maintenance is key to maximizing the lifetime of your mini excavator. One […]


If you own a Chinese mini excavator, proper maintenance is key to maximizing the lifetime of your mini excavator. One crucial maintenance aspect is routinely checking fluid levels, especially the hydraulic fluid. The hydraulic fluid acts as the “bloodstream” of the excavator, powering all hydraulic operations from digging and lifting to attaching different tools. Keeping the hydraulic fluid at the optimal level ensures smooth functionality of the mini excavator.

In this in-depth tutorial guide, we will discuss how to check hydraulic fluid on a mini excavator.

Proper maintenance, especially routine hydraulic fluid checks, is crucial for maximizing the lifespan and performance of your mini excavator.

Key Takeaways

1. Importance: Regularly checking hydraulic fluid levels ensures optimal performance and longevity of your mini excavator.

2. Procedure: Park on level ground, check fluid levels with the dipstick, and maintain optimal levels.

3. Maintenance: Address any issues like contamination or leaks promptly.

Understanding Hydraulic Fluid

The hydraulic fluid acts as a liquid force amplifier that allows excavators to function using relatively low pressures for heavy lifting and digging tasks. It has two leading roles:

Transmit power – Hydraulic fluid transmits power from the hydraulic pump (connected to the engine) to hydraulic cylinders, motors, and other components through valves, pipes, hoses, and actuators.

Lubricate parts reduce friction between metal parts in hydraulic components like cylinders, reducing wear and tear.

Some common hydraulic fluids used in mini excavators include hydraulic oil, anti-wear hydraulic fluid, environmentally-friendly biodegradable fluid, fire-resistant fluid, and low-temperature fluid. It is essential only to use the type of fluid recommended in your excavator’s manual.

Locating the Hydraulic Fluid Reservoir

The hydraulic fluid reservoir is usually located towards the back of the mini excavator body, near significant components like the hydraulic pump. It may be under a cover that must be opened to check fluid levels. Some signs that can help locate it include warning stickers mentioning “hydraulic fluid” or a manufacturer label on the reservoir cap. The reservoir cap also usually has a built-in dipstick for accurate level checks.

Checking the Fluid Level

Park the excavator on level ground and put all attachments on the ground.

Start the engine, run all attachments to their extreme positions, then turn off the engine and remove the ignition key.

Open the reservoir cap and carefully pull out the dipstick. Wipe it clean with a rag.

Check the fluid level between the ‘Full’ and ‘Low’ marks on the dipstick. If low, add the recommended fluid through the reservoir opening slowly.

For accurate checking, measure the level again after 10 minutes as fluid may temporarily rise on refill.

Always replace the reservoir cap securely after checking to prevent fluid loss or contamination.

As fluids expand with heat, a hot excavator may show higher fluid levels than specified for room temperature checks.

A woman is checking a mini excavator

Assessing Fluid Condition

In addition to level checks, regularly inspecting fluid conditions helps identify maintenance needs and potential issues. Here are some signs to watch out for:

Frothy or milky fluid indicates contaminated fluid with air, moisture, or coolant. Requires fluid flushing and filtering.

A dark brown fluid color is acceptable for older machinery. Blackish fluid indicates excessive heat breakdown and may affect performance.

A robust burnt smell signals oil breakdown from overheating. Inspect hydraulic components for leaks and overheating.

Check for metal filings in used fluid using a magnet. Indicates internal component wear requiring replacement.

Change fluid annually or as directed in the manual. The used fluid test helps identify potential issues before escalation requiring expensive repairs.

Keeping fluid clean through regular hydraulic filter changes extends fluid and excavator lifetime. Catching issues early proves more cost-effective than dealing with neglected maintenance over time.

Refilling and Maintaining Fluid Levels

It is essential to maintain optimal fluid levels indicated on the dipstick. Frequent top-ups may indicate hydraulic leaks that must be addressed to prevent fluid loss and equipment damage over time.

When refilling:

Only use the recommended fluid type for your excavator model as specified in the manual.

Clean the area around the reservoir opening before unscrewing to prevent contamination.

Slowly add fluid through a clean funnel or directly using a cleaned bottle to avoid overflow or aeration.

Allow 10 minutes for settling, and check the level as specified when the fluid is warm. Top up if needed.

Tightly close the reservoir cap after refilling to prevent fluid loss or dirt infiltration.

Maintaining fluid quality also involves changing filters, changing old fluid during services, keeping the reservoir cap tight and addressing any leaks immediately. This helps maintain performance while saving repair costs in the future.

Common Issues and Solutions

Here are some potential hydraulic fluid problems on mini excavators and solutions:

Low fluid level – Top up with recommended fluid. Find and fix leaks causing loss.

Cloudy or contaminated fluid – Drain the system, flush clean, and replace filters and fluid. Contamination caught early prevents expensive damage.

Overheated fluid – Inspect pump, pipes, and valves for leaks or issues causing overheating. Address immediately.

Water in fluid – Drain, flush and replace fluid and filters. Find the source of water ingress and rectify it.

Burnt smell – Usually indicates overheating from leaks or restricted flow. Inspect components for damage before flushing the system.

Noisy pump/motors – This may mean fluid breakdown or air in lines. Check fluid and reservoir cap, and replace filters and bleed lines if needed.

Sluggish cylinder action – Due to fluid breakdown, low levels, leaks or dirty filter. Replace filters or flush the system if sluggishness persists after refilling.

Seeping or blown seals – Loss of sealing ability due to damaged, low-quality or boiling fluid. Replace seals and change contaminated fluid.

Catching issues early allows simple troubleshooting. Neglected problems can damage expensive components, requiring repairs or part replacement.

The hydraulic system

The Role of Regular Checks

Keeping fluid levels and optimizing overall system health play key roles in mini excavator performance and longevity. While daily pre-operation checks are ideal, at minimum, fluid levels should be inspected weekly, and related maintenance should be performed monthly or as specified in the manual.

Regular fluid checks:

Prevent damage from low levels affecting functions.

Catch minor issues before escalating to force downtime and repairs.

Indicate leaks and maintenance needs addressing reliability concerns.

Help inspect system health through fluid color and contamination monitoring.

Allow prompt fluid/filter changes, keeping the system clean for smooth action.

Establishing consistent maintenance habits helps excavator ownership be cost-effective over the long run. Early detection and attention saves repair expenses down the line.


Mini excavators prove to be highly versatile equipment across industries with proper maintenance. However, upkeep requires diligence, especially when frequently overlooked fluid levels are involved.

This guide provides comprehensive fluid check understanding and troubleshooting help for excavator owners. Familiarizing with routine fluid assessments optimizes machine performance at a low cost. Regular checks help flag issues early for simple solutions, avoiding costly downtime later. Maintaining optimal fluid levels through consistent maintenance proves key to maximizing mini excavator value.


Q1. How often do you inspect a mini excavator?

A1. Inspecting that a mini excavator be inspected at least once a day or before each work shift is recommended. Some key items to check include fluid levels, leaks, hoses, filters, tracks/undercarriage condition and functionality of all components.

Q2. What kind of hydraulic fluid does a mini excavator take?

A2. Common types of hydraulic fluid used in mini excavators include hydraulic oil, anti-wear hydraulic fluid, environmentally-friendly biodegradable fluid, fire-resistant fluid and low-temperature fluid. It is important only to use the specific type of fluid recommended in your excavator’s manual.

Q3. Do you check hydraulic fluid with the engine running?

A3. No, checking hydraulic fluid levels while the engine is running is unsafe as there may be residual pressure in the lines. Ensure the engine is turned off and any attachments are secured on the ground before removing reservoir caps or dipsticks to check the fluid.

Q4: How do you check hydraulic fluid on a mini excavator?

A4: To check hydraulic fluid on a mini excavator, park on level ground, ensure the engine is off, access the hydraulic fluid reservoir, and use the dipstick to check the fluid level between the ‘Full’ and ‘Low’ marks.

Related News

Do you have any questions?

Welcome to boleo. Evolve with the brightest!