Whether you maintain your home by becoming a keen DIY-ist, work in construction, or landscaping, mini excavators are incredibly useful. But to allow them to realize their full potential, you really need to pay attention. You should check your hydraulic oil level to keep it working efficiently.
In this guide, you will learn how to check hydraulic oil level on excavator. But first, let's show you why checking hydraulic oil is such a big deal.
Why Hydraulic Oil Matters
Let's make it clear: without hydraulic oil, your machine would not work at all. The hydraulic system is responsible for power distribution throughout your excavator, so every action the machine performs happens thanks to proper hydraulic fluid levels.
Here are a few of the ways that hydraulic oil helps keep this machine functioning properly and efficiently:
Power Transmission: Hydraulic oil conveys power from the engine to different parts of the excavator. And this fluid power means the machine can deliver great force with little mechanical complexity. Your excavator can move forward and back thanks to the hydraulic track motor (left and right). This motor gets its power from oil coming from the main pump connected to the engine. The machine can also swivel around 360 degrees thanks to the slew motor, which is powered by the same hydraulic system. The hydraulic circuit connects with cylinders that operate the boom and stick as well.
Lubrication: Because the hydraulic oil passes through every moving part, it helps to lubricate them and make sure they do not actually rub against each other. By preventing untimely component failure, this lubrication extends the life of your engine. It reduces friction between metal parts in hydraulic components like cylinders, reducing wear and tear.
Heat dissipation: During the operation of the hydraulic system there is a significant generation of heat. This heat is absorbed by the oil, which it carries away from sensitive parts to aid in keeping components of your engine at ideal running temperatures and not allowing them to overheat.
Many attachments mounted on excavators - including augers, buckets, hammers, and more - work thanks to proper hydraulic flow. Now it's clear that hydraulic systems are crucial for excavator operation. Ensuring appropriate oil level is one way to make sure your excavator runs smoothly and efficiently, day after day.
Understanding how to maintain excavator hydraulic system health through regular oil checks is fundamental to equipment longevity. These are already enough reasons to check your oil levels. Your mini excavator will thank you.
Safety First: Proper Preparation
Before officially starting the hydraulic oil level inspection, you must ensure that the operating environment and equipment status are in safe and stable conditions. Many times, the problem with incorrect inspection methods lies not in the steps themselves, but in the preparation. To avoid misreading the liquid level or potential risks, you need to complete the necessary safety checks and preparations before operating.
Before you can check anything, you need to ensure proper safety. Always park your machine on level ground - this gives you the most accurate reading possible. If the excavator is parked on a slope, the hydraulic oil in the tank will be unevenly distributed, causing inaccurate oil level readings. It's recommended to park the excavator on compacted concrete or hard-packed dirt, rather than soft soil, slopes, or potholes.
The excavator should be switched off completely, and you should take the key out of the ignition. This prevents accidental starting of the equipment. Even if you temporarily leave the inspection location, leaving the key in the ignition could cause the engine to start by accidentally touching the lever or someone else's mistake.
One thing that may not be obvious: make sure there's no pressure in the tank before you remove any cap. Also, let the engine cool down if it's been running hot, as working with hot oil could be dangerous. After operating the excavator, the hydraulic oil temperature may reach 60-80°C. If you open the oil level inspection cover or fuel tank cap at this time, the high-temperature oil may splash out due to pressure and burn your hands, face, and other parts of your body. It is recommended to wait for 15-30 minutes after stopping the machine (the specific time can be adjusted according to the ambient temperature) and wait until the oil temperature drops below 40°C (the outer wall of the oil tank should not be hot to the touch) before operating.
Wear appropriate personal protective equipment (PPE), such as gloves and safety glasses. During the inspection, you may come into contact with oil stains or metal parts or be exposed to the risk of oil splashes. Gloves can protect your hands from oil stains and scratches from parts. Safety glasses can prevent oil and dust from splashing into the eyes.
Required Tools and Items
After confirming the safety measures, preparing the appropriate tools and supplies will ensure a smooth hydraulic oil level check. You need to prepare the following items in advance and confirm their status.
First you need to prepare a clean cotton or lint-free cloth. This type of cloth can clean oil and dust from the surface of the oil level gauge. When opening the fuel filler cap, you can wipe off any debris around the cap to prevent it from falling into the fuel tank and contaminating the oil. If you use old towels, ordinary rags, and other lint-shedding materials, the lint can easily enter the fuel tank during operation, thereby clogging the hydraulic pipeline or wearing out the hydraulic pump.
Secondly, gloves must provide both cleanliness and protection. They prevent hand sweat, dust, and oil from coming into direct contact with the oil level gauge and filler cap, preventing impurities from entering the fluid. They also provide a non-slip and scratch-resistant surface when opening the oil cap and touching the outside of the tank. It is recommended to give priority to nitrile gloves that are wear-resistant and not easy to absorb oil, rather than cotton gloves that are easy to absorb oil and difficult to clean.
You should prepare appropriate containers if necessary. This type of container is only used in specific scenarios. For example, when the oil level is found to be too high and excess oil needs to be drained, or when the oil level is too low and new oil needs to be added. The container needs to be cleaned and dried in advance to avoid residual moisture and impurities contaminating the oil.
Finally, you'll need tools such as wrenches to open the fuel filler cap, depending on the model. Not all models require this tool. Some excavators have a manually unscrewed oil level inspection cap that requires no additional tools. However, the fuel filler caps on some heavy-duty models or older equipment may become rusted, screwed shut, or have bolts securing them due to long-term use. At this time, you need to prepare open-end wrenches and ring wrenches of matching specifications. Be careful to avoid using an adjustable wrench, as it can slip and damage the cover threads. It's recommended to confirm the fuel filler cap structure of your model in advance to avoid delays due to missing tools.
Step-by-Step Guide: How to Check Hydraulic Oil Level on Excavator
Good hydraulic oil maintenance starts with scheduled checks. Here is how to check your mini excavator hydraulic oil level the right way:
Step 1: Park on Level Ground
Park the mini excavator on level ground. It also provides an accurate oil level reading, eliminating false low or high readings.
Step 2: Lower Attachments
Fully lower the boom, arm, and bucket. This drains the most amount of hydraulic oil back to the reservoir which will increase your accuracy when checking for proper fluid level in the system. If you have hydraulic attachments like thumb clips installed, ensure they're also in their resting position.
Step 3: Shut Down the Machine
Turn off your mini excavator and let it cool down for at least 30 minutes or more. As fluids expand with heat, a hot excavator may show higher fluid levels than specified for room temperature checks.
Step 4: Find the Oil Reservoir
You'll need to locate the hydraulic oil tank and an indicator for reading the oil level. Find the Hydraulic Oil Reservoir (See where your manual tells you to fill hydraulic oil). The location of the hydraulic oil tank is usually fixed. Most excavators place it behind the counterweight or on the side of the fuselage for easy refueling and inspection. It is usually marked with a hydraulic oil symbol. The specific location can be confirmed according to the equipment manual or model identification.
Step 5: Area Cleaning
Clean the area around your oil reservoir cap or dipstick before you open it. This way, contaminants do not enter the system during inspection.
Step 6: Check the Oil Level
Mini excavators differ. On some models, you will have a sight glass for checking the oil levels. On other models, you'll have the typical dipstick.
Dipstick: This is the most common way to check the oil level; it is typically attached to the hydraulic oil filler cap.
Sight Glass: Some excavators have a transparent, round or strip-shaped window mounted on the side of the oil tank.
Method 1: Dipstick Method
This method works if your excavator has a dipstick for hydraulic oil level checks. It's easier than you might think.
The dipstick is usually found near the hydraulic pump or reservoir with the fluid. Look for a stick marked "hydraulic" or with the hydraulic symbol. Once you locate it, clean the dipstick thoroughly with a cloth or rag to get rid of any dirt or debris - this ensures an accurate reading every time.
During operation, it is necessary to judge separately according to the cold and hot car states to ensure accurate readings:
Cold Engine Check (Static Oil Level): Turn off the engine and let it sit for at least 30 minutes to allow the hydraulic oil to drain back into the tank. Remove the dipstick and dry it with a clean lint-free rag. After that push in all the way back then pull it out again to check the oil level. The oil level should remain between the MIN and MAX marks on the dipstick. If it is low, you will need to add hydraulic fluid.
Warm Engine Check (Dynamic Oil Level): Start the engine and operate all equipment for 5-10 minutes to allow the hydraulic oil to reach normal operating temperature. Then, immediately turn off the engine and check the dipstick. The liquid level at this time is usually closer to the MAX line, which better reflects the oil level status of the equipment under actual working conditions.
Take care when pouring new oil into the hydraulic oil tank - go slowly to avoid spills. If you need to remove excess oil, use a turkey baster or small pump to extract it without making a mess. At this stage, it's crucial to use the correct oil type for your engine model.
After adding or removing fluid, make sure the oil level is right where it should be. Insert the dipstick back into the hydraulic reservoir and check that the mark falls in the proper range. If it's still not right, repeat the previous step until you get it just right.
Method 2: Sight Glass Method
This method applies if your excavator has a dedicated sight glass for hydraulic oil level checks. The sight glass looks like a tiny clear window or panel located right next to the hydraulic pump or reservoir. It'll be labeled with a special symbol or the word "hydraulic."
Before inspection, use a cloth or rag to wipe it clean - you need a clear view to get an accurate reading.
Observe the oil level with the engine either cold or hot, as directed by the manual. The hydraulic oil level should be maintained between the upper and lower scale lines on the sight glass, with the ideal position usually close to the middle. The oil should be clearly visible, and you should be able to see its color - clean oil typically looks clear or amber, while dirty oil may appear dark or cloudy.
If the level is too low, replenish the hydraulic oil promptly. If it is too high, use a turkey baster or small pump to extract excess oil. Always make sure you use the correct hydraulic oil type for your specific engine model.
After making adjustments, look through the sight glass again to ensure the fluid level is properly positioned between the high and low marks. If it's still not right, repeat the process from the previous step. If you find that the oil sight glass is blurred due to long-term oil pollution, you should consider further cleaning or replacing it to avoid affecting your judgment.
Hydraulic oil can be added through the reservoir filler neck or top inspection plate. Different manufacturers have different designs, though the fill location might be identified by the hydraulic level symbol.
Step 7: Check Oil Quality
In addition to monitoring the level, inspect the oil's condition to identify maintenance needs and potential issues. Here are some signs to watch out for:
Color: Clean hydraulic oil should be translucent and amber in color. A dark brown fluid color is acceptable for older machinery. Dark or cloudy oil may indicate contamination or degradation. Blackish fluid indicates excessive heat breakdown and may affect performance.
Smell: Hydraulic oil when clean, fresh, and uncontaminated, has a mild characteristic odor. A burnt smell (due to overheating) and a sour-smelling odor (chemical breakdown) are not good signs. A robust burnt smell signals oil breakdown from overheating. Inspect hydraulic components for leaks and overheating.
Texture: Apply a small amount of oil to your fingers. It should feel smooth. If there is any grit, it has been contaminated with particulates.
Frothy or milky fluid indicates contaminated fluid with air, moisture, or coolant. Requires fluid flushing and filtering.
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.
Step 8: Keep a Record of the Results
Track your oil checks noting the date, level, and in general, how the oil seems to you. You can then reference this record to detect patterns and predict maintenance requirements.
Low Hydraulic Fluid Symptoms to Watch For
Being proactive in identifying potential issues can save you time and money. Here are some key symptoms that might indicate low hydraulic fluid:
- Slow or erratic movement of hydraulic components
- Unusual noises, such as whining or cavitation sounds
- Higher than normal operating temperatures
- Visible leaks under the machine or around hydraulic components
- Loss of power or reduced lifting capacity
- Difficulty in controlling the excavator's movements
Any of these symptoms can point to poor quality or low oil level. Check hydraulic oil levels immediately. The earlier you address any issues before operating the machine, the better.
Additional Maintenance Tips
Maintaining optimal hydraulic oil levels ensures smooth operation of your mini excavator. Beyond just checking fluid levels, comprehensive hydraulic system care involves several key practices:
Filter Changes: Regularly replace hydraulic filters according to your manufacturer's recommendations. Clean filters prevent contaminants from damaging your system. For machines in active use, change hydraulic filters every 6 months or 200 hours during heavy operation seasons.
System Inspection: Inspect hoses, fittings, and seals for leaks or wear. Ensuring your machine has an adequate amount of hydraulic oil will prove frivolous if it does not remain at such a level after some operation. It is essential to fix any leaks before going any further.
Oil Analysis: Consider sending oil samples for analysis periodically. This can reveal internal wear issues before they become serious problems.
Temperature Management: Monitor hydraulic oil temperature during operation. Excessive heat could break down the oil and damage parts.
The Importance of Quality Hydraulic Fluid for Excavator
The vast majority of modern hydraulic excavators use ISO46 as the hydraulic fluid. This is an appropriate replacement for ISO32 that was often used in older plant and agricultural machinery with gear pumps. In some applications, hydro-static systems, 10W is recommended over ISO46, although their properties are similar. These oils (10W and ISO46) can be mixed, though it is not recommended.
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 important only to use the specific type of fluid recommended in your excavator's manual.
Using high-quality excavator hydraulic oil can:
- Improve system efficiency
- Extend component life
- Enhance performance in extreme temperatures
- Reduce maintenance costs over time
Only use the hydraulic fluid for mini excavator specified by your manufacturer for your particular machine. Using an off-brand mini excavator hydraulic oil or improper substitutes is just asking for performance issues and premature hydraulic failures. Always use the hydraulic fluid recommended by your excavator's manufacturer.
Mistakes to Avoid When Checking Hydraulic Fluid
Avoid these common errors to ensure accurate readings and proper maintenance:
- Checking on uneven ground: This can lead to false readings.
- Overfilling: Too much oil can cause foaming and system damage.
- Using the wrong type of fluid: Always use the manufacturer-recommended oil.
- Neglecting to clean the area: Dirt entering the system can cause significant problems.
- Ignoring small leaks: Address any leaks promptly to prevent system failure.
Do You Check Hydraulic Fluid Hot or Cold?
This is a common concern among excavator operators. No matter what state the oil is in, your best bet for a trustworthy reading comes if it's cool. Here's why:
- Hot oil expands, which can lead to overfilling if checked when warm.
- Checking cold oil gives you a more consistent baseline for comparison over time.
- The oil is cooler and therefore if you splash yourself, there will be less injury.
But again, this varies with recommendations from the machine's maker so always use your manual.
Remember, adding too much oil can be just as problematic as having too little. Always aim for the manufacturer's recommended level.
Recommended Hydraulic Oil Check Schedule
| Operating Conditions | Check Frequency | Oil Change Interval |
|---|---|---|
| Daily heavy use | Before each shift | Every 1,000 hours |
| Regular use (3-4 days/week) | Weekly | Every 1,200 hours |
| Light/occasional use | Every 2 weeks | Annually |
| Harsh environments | Daily | Every 800 hours |
| Storage/inactive | Monthly | Before reactivation |
Troubleshooting Common Hydraulic Oil Issues
Problem: Oil level drops quickly
- Check for visible leaks around hoses and fittings
- Inspect cylinder seals for wear
- Examine the hydraulic pump for damage
- Verify all hydraulic connections and attachments are properly sealed
Problem: Oil appears milky
- Water contamination - check for damaged seals
- Drain and replace oil immediately
- Inspect cooling system for leaks
- Allow proper cool-down time before checking levels
Problem: Foamy oil
- Air in the system - check for loose connections
- Oil level too high - drain excess
- Wrong oil type - verify manufacturer specifications
- Check for worn or damaged hydraulic pump seals
Problem: Excessive noise from hydraulic system
- Low oil level - top up immediately
- Contaminated oil - change oil and filters
- Air in hydraulic lines - bleed the system
- Worn hydraulic pump - inspect and replace if necessary
Frequently Asked Questions (FAQs)
Q: How often should I check the hydraulic oil level on my mini excavator?
A: Check the hydraulic oil level before each day's operation, or at minimum once a week for regular use. For intensive operations, check it daily. Reference the schedule table above for specific guidance based on your usage pattern.
Q: What happens if I run my excavator with low hydraulic oil?
A: Running with low hydraulic oil can cause pump cavitation, overheating, reduced performance, and potentially catastrophic system failure requiring expensive repairs. Low oil also accelerates wear on hydraulic components and can damage seals and cylinders.
Q: Can I use automotive engine oil in my excavator's hydraulic system?
A: No, never use engine oil in hydraulic systems. Always use the specific hydraulic oil (typically ISO 46) recommended by your excavator manufacturer. Engine oil lacks the necessary viscosity and additives for hydraulic systems.
Q: How long does hydraulic oil last in a mini excavator?
A: Typically 1,000-2,000 operating hours or annually, whichever comes first. However, always follow your manufacturer's specific recommendations. Proper maintenance can extend equipment service life beyond 9,000 hours.
Q: What color should hydraulic oil be?
A: Fresh hydraulic oil should be translucent amber. Dark brown is acceptable in older machines, but black or milky oil indicates problems requiring immediate attention. Clear amber means the oil is clean and functioning properly.
Q: Can I mix different types of hydraulic oil?
A: While ISO 46 and 10W hydraulic oils can technically be mixed, it's not recommended. Different oil types have varying additive packages that may not be compatible. Always use the same type and brand when topping up.
Q: Why is my hydraulic oil foamy?
A: Foamy oil typically indicates air in the system, overfilling, or using the wrong oil type. This can cause poor performance and accelerated wear. Check your oil level, verify you're using the correct oil specification, and inspect for air leaks in the system.
Q: Should I check hydraulic oil with the engine running?
A: No, always check hydraulic oil levels with the engine off and after allowing 15-30 minutes for the oil to settle and cool down. This provides the most accurate reading and is safer.
Conclusion
Ensuring the proper level of hydraulic oil in excavators is a routine maintenance task and a crucial aspect of preserving the integrity and functionality of your machine. Neglecting to check hydraulic oil levels can lead to a cascade of issues, from costly repairs to significant downtime.
The strategies we've covered in this guide will elongate your machine's life. They will also make it operate more efficiently and reliably on job sites. As we always say: proactive maintenance is cheaper than reactive repairs.
By following the advice above (and your machine-specific manual), your machine will stay in great condition for years and it will be a reliable piece of gear to power through any kind of job. No need for hydraulic system failure to thwart your projects or raise your operating expenses.
Regular inspections can effectively prevent hydraulic component wear, operational stalls, and other problems caused by abnormal oil levels and can also reduce equipment downtime and maintenance costs. Whether you're operating a compact 0.9-ton model or a larger 2-ton excavator, proper hydraulic oil maintenance is essential for peak performance and longevity.