A dishwasher is designed to save time and ensure your dishes come out spotless. When grease or residue remains after a wash cycle, it indicates that the appliance is not performing properly. Ignoring the issue can lead to hygiene concerns, unpleasant odors, and eventual component failure.
This guide explains the most common reasons dishwashers leave grease behind, what you can check as a homeowner, and when to call a trained technician.
How Dishwashers Clean Effectively
A dishwasher’s cleaning ability depends on several components working together: water temperature, spray pressure, detergent quality, filtration, and drainage. If one of these systems fails, cleaning results become inconsistent.
Common Causes of Greasy Dishes
1. Low Water Temperature
Dishwashers need sufficiently hot water to dissolve grease. If the water heater or internal heating element fails, grease will remain on dish surfaces.
Recommended temperature range: 120–140°F.
2. Clogged Spray Arms
Spray arms distribute pressurized water throughout the tub. Over time, mineral deposits and food particles can block the spray holes, reducing cleaning effectiveness.
3. Poor Detergent Quality
Low-grade detergent, expired detergent, or insufficient detergent use can prevent grease from breaking down. Hard water conditions may also reduce detergent efficiency.
4. Blocked or Dirty Filter
A dirty filter prevents proper drainage and causes grease-filled water to circulate back onto dishes. Regular cleaning is essential to maintain wash quality.
5. Malfunctioning Pump
The wash pump controls water pressure. If the pump is weak or failing, dishes will not receive adequate spray coverage.
6. Faulty Heating Element
If the heating element does not raise water to proper temperature, detergent activation weakens and grease remains on dishes.
7. Improper Loading
Incorrect dish placement can block spray arms and restrict water flow, leaving some dishes under-cleaned.
Warning Signs
- Greasy film or residue on dishes
- Cloudy glasses
- Food particles on plates
- Bad odor after cycle
- Standing water inside dishwasher
These issues typically indicate filtration, temperature, or pump problems.
What You Can Check Yourself
Before contacting a technician, try the following:
- Confirm hot water supply is functioning
- Use a high-quality detergent
- Clean spray arms and filters
- Avoid overloading the dishwasher
- Ensure dishes face the spray direction
- Run hot water in the sink before starting the cycle
If these steps do not improve results, internal failure is likely.
How Technicians Diagnose the Issue
A technician may:
- Test the heating element
- Measure water temperature
- Inspect spray arms and pump
- Check drainage and filter system
- Examine detergent dispenser
- Review water pressure and inlet valve performance
- Inspect control board and sensors
Accurate diagnosis ensures that only necessary parts are repaired or replaced.
Professional Repair Solutions
Professional service may include:
- Heating element replacement
- Pump repair or replacement
- Filter system cleaning
- Spray arm replacement
- Water inlet valve repair
- Control board diagnosis and repair
Proper repairs restore cleaning performance and extend appliance lifespan.
Repair or Replace?
Repair is recommended when:
- Issues are limited to the heating element, pump, or filter
- The dishwasher is less than 8–10 years old
Replacement is often better when:
- Multiple major components fail
- The control board is faulty
- Repairs exceed the unit’s value
- The appliance is over 10–12 years old
A technician can help you make the most cost-effective decision.
Preventing Grease Buildup
- Clean filters regularly
- Run monthly cleaning cycles
- Use high-quality detergent
- Avoid overloading racks
- Maintain proper water heater temperature
- Schedule periodic maintenance
Routine care ensures long-term cleaning performance.
Professional Dishwasher Repair in Northern Virginia
If grease remains on your dishes even after troubleshooting, professional repair is the safest solution. Your HVAC Partner provides expert dishwasher repair throughout Northern Virginia, servicing all major brands and models with reliable diagnostics and efficient repairs.