The radiator is one of the most important components in the cooling system of a VT, VX, or VY Commodore. Whether your vehicle is powered by an Ecotec V6, Supercharged V6, LS1 V8, or Alloytec engine, the radiator is responsible for removing heat from the coolant and maintaining safe engine operating temperatures.
As these Commodores age, radiator failures are becoming increasingly common. Plastic end tanks become brittle, cores become clogged, and leaks begin to develop. Replacing a worn radiator before it fails completely can prevent overheating and costly engine damage.
Why Radiators Fail
Most original radiators are now over 20 years old.
Common Causes
- Plastic tank deterioration
- Heat cycling
- Corrosion
- Internal blockage
- Cooling system neglect
- Physical damage
Over time, even well-maintained radiators eventually reach the end of their service life.
Signs Your Radiator Needs Replacing
1. Coolant Leaks
The most obvious sign.
Symptoms
- Coolant on the ground
- Low coolant level
- Coolant smell after driving
Leaks commonly occur around the plastic end tanks.
2. Overheating
A failing radiator may lose cooling efficiency.
Symptoms
- Temperature gauge rising
- Overheating in traffic
- Poor cooling performance
3. Cracked Plastic End Tanks
A very common VT–VY issue.
Symptoms
- Visible cracks
- Coolant seepage
- Sudden coolant loss
4. Internal Blockages
Over time, coolant passages can become restricted.
Symptoms
- Poor cooling performance
- Hot running engine
- Uneven radiator temperatures
5. Corrosion
Neglected coolant accelerates corrosion.
Symptoms
- Discoloured coolant
- Corroded radiator fins
- Cooling system contamination
Tools Required
Recommended Tools
- Socket set
- Screwdrivers
- Drain pan
- Hose clamp pliers
- Funnel
- Safety gloves
Having all tools ready makes the job significantly easier.
Parts Recommended During Replacement
Many cooling system components are easy to access while the radiator is removed.
Consider Replacing
- Upper radiator hose
- Lower radiator hose
- Thermostat
- Hose clamps
- Radiator cap
- Coolant
Preventative maintenance can save labour later.
Step 1: Allow Engine to Cool
Never work on a hot cooling system.
Safety Warning
Hot coolant can cause serious burns.
Allow the engine to cool completely before beginning.
Step 2: Drain the Cooling System
Place a drain pan underneath the radiator.
Procedure
- Open radiator drain
- Remove radiator cap
- Allow coolant to drain completely
Dispose of coolant responsibly.
Step 3: Remove Intake Components
Depending on engine type, some intake ducting may need removal.
Typical Components
- Air intake pipe
- Airbox connections
Step 4: Disconnect Radiator Hoses
Remove:
Hoses
- Upper radiator hose
- Lower radiator hose
- Overflow hose
Inspect hoses for deterioration.
Step 5: Disconnect Transmission Cooler Lines
Automatic models have integrated transmission coolers.
Important
Place rags beneath fittings to catch fluid.
Inspect lines for leaks or damage.
Step 6: Remove Thermo Fan Assembly
Most VT–VY Commodores use electric thermo fans.
Procedure
- Disconnect electrical connectors
- Remove retaining fasteners
- Lift fan assembly out
Step 7: Remove Radiator Mounting Brackets
Remove:
- Upper retaining brackets
- Mounting hardware
Keep fasteners organised for reinstallation.
Step 8: Remove Old Radiator
Carefully lift the radiator upward.
Inspect
- Mounting rubbers
- Support brackets
- Cooling fins
Replace damaged mounting components.
Step 9: Install New Radiator
Position the replacement radiator carefully.
Ensure
- Correct fitment
- Proper mounting alignment
- No interference with fan assembly
Step 10: Reinstall Components
Reinstall:
- Radiator brackets
- Fan assembly
- Hoses
- Transmission cooler lines
- Intake components
Double-check all connections.
Step 11: Refill Cooling System
Use the correct coolant mixture.
Recommended
- Quality long-life coolant
- Demineralised water
- 50/50 mix
Follow Holden cooling system specifications.
Step 12: Bleed the Cooling System
Air pockets can cause overheating.
Procedure
- Run engine
- Monitor coolant level
- Top up as required
- Ensure heater operates correctly
Step 13: Check for Leaks
Inspect:
- Hose connections
- Drain plug
- Transmission cooler fittings
Address any leaks immediately.
Common Mistakes During Radiator Replacement
Reusing Old Hoses
Old hoses frequently fail shortly after radiator replacement.
Not Bleeding the Cooling System
Air pockets can cause overheating.
Reusing Old Coolant
Fresh coolant should always be used.
Forgetting Transmission Cooler Connections
Can result in transmission fluid leaks.
Choosing the Right Replacement Radiator
Standard Replacement
Suitable for most daily-driven vehicles.
Heavy-Duty Radiator
Ideal for:
- Towing
- Hot climates
- Modified engines
Aluminium Performance Radiators
Popular among LS1 owners.
Benefits
- Improved cooling efficiency
- Increased durability
Common Radiator Problems After Installation
Coolant Leaks
Usually caused by loose clamps.
Overheating
Typically due to trapped air.
Transmission Fluid Leaks
Often linked to cooler line connections.
How Long Does a Radiator Last?
Typical lifespan:
Expected Life
- 10–20 years depending on maintenance
Regular coolant changes help maximise lifespan.
Preventing Future Radiator Problems
Maintain Coolant Quality
Corrosion protection is essential.
Replace Coolant Regularly
Old coolant promotes internal deterioration.
Repair Small Leaks Early
Prevents larger cooling system failures.
Keep Cooling Fins Clean
Improves airflow and cooling efficiency.
Radiator replacement is a common maintenance task for VT, VX, and VY Commodores as original cooling system components continue to age. Fortunately, replacing a radiator is a relatively straightforward job that can dramatically improve cooling performance and reliability.
By replacing worn hoses, using quality coolant, and properly bleeding the cooling system, owners can prevent overheating and extend the life of their Ecotec, Supercharged V6, LS1, or Alloytec engine for many years to come.
Related Articles
- Best Coolants for Ecotec Engines
- Ecotec Intake Manifold Gasket Problems
- Common Ecotec Engine Problems
- VT, VX, VY Transmission Service Guide