Mercedes-Benz Radiators

How to Fix a Radiator Leak in Your Mercedes

A radiator leak might start small, but ignoring it can lead to engine overheating, loss of coolant, or long-term engine damage. If you're confident with basic DIY skills, small radiator leaks can often be handled at home with the right tools and a little patience. For your Mercedes-Benz E-Class, using these tips to address a leak quickly can save you from costly repairs:

Expert Tips for DIY Radiator Fixes in Your E-Class

1. Let the Engine Cool Completely

Never attempt to inspect or open the radiator cap while the engine is hot—wait at least 30–45 minutes after shutting off your vehicle.

2. Inspect for Visible Damage

Look for white residue, coolant stains, or wet spots near the radiator, hoses, and clamps to locate the source of the leak.

3. Use a Radiator Stop Leak Product

For very small leaks, a radiator stop leak additive may offer a temporary fix—just pour it in through the radiator cap and run the engine.

4. Tighten or Replace Hose Clamps

Loose clamps around hoses can be the cause of coolant leaks; tightening or replacing them might solve the issue without further repairs.

5. Replace Damaged Hoses

If any radiator hose feels brittle or shows cracks, swap it out with a fresh part to prevent future leaks and improve coolant flow.

6. Pressure Test the System

Using a radiator pressure tester can help identify slow leaks by simulating normal operating pressure while the engine is off.

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