Compressor Oil Temperature Above Warning Threshold
The ATLAS-COPCO-E005 (Atlas Copco Xc4002 / Xc2003 / Xc4004) diesel fault code means: Compressor Oil Temperature Above Warning Threshold. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- DIY cleaning and belt replacement: $20-$150 in parts. Oil and filter service: $80-$200 in parts. Pro thermostatic valve replacement or sensor diagnosis: $300-$700 including labor at a rental service center.
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Common Symptoms
- Xc4002 / Xc2003 / Xc4004 LCD on the side panel displays E005 and the unit shuts down or derate begins
- Oil temperature warning lamp or red fault LED lights up on the control panel
- Unit may continue running briefly at reduced output before tripping to STOP
- Compressor outlet air feels hotter than normal at the service valve
- Oil cooler fins are visibly clogged with dirt, debris, or dried mud
- Unit shuts down and will not restart until oil temperature drops below reset threshold
- Fan belt slipping or cooling fan running slower than normal and audible belt squeal present
Probable Causes (Ranked by Likelihood)
- Oil cooler core blocked with dirt, dust, or construction debris restricting airflow Very Likely
- Low compressor oil level causing insufficient heat absorption and circulation Very Likely
- Ambient temperature extremely high combined with inadequate ventilation around the unit Likely
- Cooling fan drive belt slipping, broken, or missing, reducing airflow across the oil cooler Likely
- Thermostatic bypass valve stuck open or failed, allowing oil to bypass cooler continuously Possible
- Wrong viscosity or contaminated compressor oil causing elevated operating temperatures Possible
- Oil temperature sensor fault or wiring issue sending false high reading to the controller Less Likely
Step-by-Step Diagnostic Procedure
Check the Xc4002 / Xc2003 / Xc4004 LCD on the side panel for the E005 code and note whether the unit tripped to STOP automatically or is still running in a derate condition. Press STOP if the unit is still running before proceeding.
Inspect the compressor oil level using the sight glass or dipstick on the airend oil separator tank. Oil must be within the marked operating range. Top off with the correct Atlas Copco compressor oil grade if low.
Inspect the oil cooler core from both sides. Use compressed air or a brush to clear any mud, dust, grass, or construction debris from the fins. This is the most common cause on rental fleet machines. Do this before anything else.
Check the cooling fan drive belt for wear, cracks, glazing, or slippage. Deflect the belt with your thumb. More than 1/2 inch of free play typically means the belt is loose. A glazed or slipping belt will cut cooling airflow dramatically.
Check the ambient temperature and the machine's surroundings. If the unit is parked in direct sun against a wall or inside an enclosure, move it to open air and allow at least 3 feet of clearance on all ventilation sides. Verify the thermostat-controlled cooling fan engages when the unit is under load.
After clearing debris and confirming oil level, restart the unit and let it reach operating temperature under load. Monitor the oil temperature reading on the Xc4002 / Xc2003 / Xc4004 LCD. Normal operating oil temperature for most XAS platforms is below 230 degrees F (110 degrees C). If temperature still climbs above threshold, suspect the thermostatic bypass valve or oil contamination.
To check the thermostatic bypass valve, compare oil-in and oil-out temperatures at the cooler connections after a full warm-up run. If oil-in and oil-out temperatures are nearly identical even after the cooler has been cleaned, the bypass valve is likely stuck open and is bypassing hot oil around the cooler. This step requires a contact or infrared thermometer.
If all mechanical checks pass and E005 persists, use DiagPro service software via the J1939 / CAN data port to read the live oil temperature sensor value and compare it against a calibrated contact thermometer reading on the oil separator tank. A large discrepancy means the sensor or its wiring circuit is faulty. Sensor diagnosis and controller calibration require DiagPro and a trained Atlas Copco service tech.
Frequently Asked Questions
What does Atlas Copco code E005 mean?
E005 means the Xc4002 / Xc2003 / Xc4004 controller has detected compressor oil temperature above the warning threshold. The most common cause on jobsite machines is a clogged oil cooler or low oil level. The unit will shut down or derate to protect the airend from heat damage.
Can the compressor still run with E005 active?
Briefly, yes, in some controller configurations the unit will continue to run with reduced output while the warning is active. But if the oil temperature keeps climbing, the controller will trip the unit to STOP automatically. You should not force it to keep running. Overheating the airend can seize rotors and turn a cheap maintenance item into a multi-thousand-dollar rebuild.
How much does it cost to fix E005?
If the cause is a dirty oil cooler or a loose fan belt, you are looking at a DIY cleaning job that costs almost nothing, or a belt for $20-$80. If the oil needs a full service, expect $80-$200 in oil and filter parts. A failed thermostatic bypass valve or sensor diagnosed and replaced by a shop will typically run $300-$700 with labor.
Will the compressor start again after E005 shuts it down?
On most XAS platforms with the Xc4002 / Xc2003 / Xc4004 controller, the unit will allow a restart after the oil temperature drops back below the reset threshold and you clear the fault with the STOP and AUTO sequence. However, if you restart without fixing the root cause, E005 will return quickly and could escalate to the critical shutdown code E006, which may require a controller reset by a service tech.