BMW Radiator Types and When to Replace

Radiator Construction

BMW radiators use aluminum cores with plastic end tanks. The plastic tanks are the weak point — they become brittle with age and heat cycling.

When to Replace

Signs of Radiator Failure

1. Visible cracks in plastic end tanks
2. Coolant weeping from tank-to-core seam
3. Discoloration — brown/yellow staining on tanks indicates heat damage
4. Coolant loss with no other visible leak
5. Overheating — partially clogged radiator reduces cooling capacity

Preventive Replacement

• E46: Replace at 100,000-150,000 km as part of cooling system refresh
• E90: Replace if showing any signs of age
• F30+: More durable but still inspect at 100,000+ km

OEM vs Aftermarket

Brand	Type	Quality	Price
Behr/Mahle	OEM supplier	Excellent	€200-400
Nissens	Aftermarket	Very Good	€150-300
CSF	Performance	Excellent	€300-500
Mishimoto	Performance	Good	€250-450

Performance Radiators

For tuned or track cars, upgraded radiators offer:

• All-aluminum construction — no plastic to crack
• Larger core — more cooling capacity
• Higher fin density — better heat transfer
• Direct fit — bolt-in replacement

Popular for N54/B58: CSF, Mishimoto, Wagner

Maintenance

• Flush coolant every 2 years
• Inspect radiator during every oil change
• Check for debris blocking airflow (bugs, leaves)
• Ensure radiator fans are functioning properly