Common Mistakes Auto Technicians Make (And How to Avoid Them)

Perfect for: Auto technicians, crane technicians, mechanics, electricians & AC specialists.
# Common Mistakes Auto Technicians Make (And How to Avoid Them)

Auto technicians work in high-pressure environments where one small mistake can waste time, damage expensive parts, and disappoint customers. Whether you work on cars, trucks, cranes, or heavy equipment, avoiding simple mistakes can save you hours of headache.

In this blog, we will discuss the most common mistakes technicians make, the symptoms, and the correct method to avoid them.

 

# 1. Misdiagnosing AC Problems

#Mistake

Charging gas without checking pressures, leaks, airflow, or compressor condition.

#What happens

* High side stays low

* Low side drops

* Compressor fails again

* AC cools only while driving

* Pipes frost or high pressure rises dangerously

#Correct Method

✔️ Check condenser airflow

✔️ Verify compressor clutch or control valve

✔️ Measure high-side & low-side pressures

✔️ Test expansion valve sensor

✔️ Flush system when replacing compressor

# 2. Not Flushing AC System When Replacing Compressor

#Mistake

Replacing a burnt compressor but not cleaning the debris.

#What happens

* New compressor also fails

* Blockage at expansion valve

* Oil circulation stops

* Cooling becomes weak

#Correct Method

✔️ Flush evaporator & hoses

✔️ Replace receiver drier

✔️ Use correct PAG oil

✔️ Vacuum system for minimum 20 minutes

#3. Ignoring Electrical Connection Faults

#Mistake

Replacing sensors without testing wiring.

#What happens

* Same fault still comes

* CAN communication errors

* False temperature or pressure readings

* Fan clutch not engaging

#Correct Method

✔️ Check continuity

✔️ Check voltage supply

✔️ Check ground

✔️ Inspect for corrosion & broken pins

✔️ Use proper wiring diagram

# 4. Wrong Diagnosis in Cooling System

#Mistake

Changing thermostat, radiator, or pump without confirming actual reason.

#What happens

* Overheating still comes

* Fan clutch free spin

* Coolant overflow

* Engine derates

#Correct Method

✔️ Test fan clutch operation

✔️ Pressure-test radiator cap

✔️ Bleed cooling system

✔️ Check coolant flow with engine running

✔️ Use infrared thermometer

# 5. Not Using Proper Tools

#Mistake

Using guesswork instead of tools.

#What happens

* Wrong diagnosis

* Customer loses trust

* Damage to expensive components

#Correct Tools Needed

* Multimeter

* AC manifold gauge

* Scanner/diagnostic tool

* Thermal camera

* Hydraulic pressure gauge

# 6. Skipping Basic Checks Before Major Repairs

#Mistake

Jumping directly to “big parts replacement.”

#What should be checked first

✔️ Fuses

✔️ Relays

✔️ Loose connectors

✔️ Air filters

✔️ Oil levels

✔️ Belt tension

These small checks save hours.

# 7. Poor Hydraulic Diagnosis (Common in Cranes)

#Mistake

Blaming hydraulic pump without checking:

* Filter blockage

* Relief valve stuck

* Oil contamination

* Control valve leakage

#Correct Method

✔️ Check hydraulic pressure

✔️ Inspect filters

✔️ Test pump flow

✔️ Check temperature of hydraulic oil

# 8. Not Following Torque Specifications

#Mistake

Over-tightening or under-tightening bolts.

#What happens

* Engine leaks

* Broken bolts

* Compressor mount damage

* Wheel coming loose

#Correct Method

✔️ Always use torque wrench

✔️ Follow manufacturer torque chart

#9. Poor Record-Keeping

#Mistake

Not recording:

* Oil change dates

* Hydraulic filter hours

* Parts replaced

* Fault codes

#Result

Repeat failures and no service history.

#Correct Method

✔️ Maintain logbook

✔️ Take photos before/after

✔️ Save fault codes

# 10. Lack of Continuous Learning

Technology is changing fast — hybrid systems, electronic compressors, CAN BUS, ADAS.

Technicians who do not learn will struggle.

#Solution

✔️ Watch online technical videos

✔️ Use manufacturer manuals

✔️ Join technician groups

✔️ Learn electrical diagrams

#Conclusion

Avoiding these common mistakes can save time, prevent part failures, and build customer trust. Whether you repair cars, trucks, or heavy machinery like cranes, following proper diagnostic step will make your work faster and more professional.