How to Fix a Car Radiator Leak?
3 Answers
Car radiator leaks can be addressed by: 1. Taking the vehicle to a repair shop for inspection and replacing the radiator if necessary; 2. If the leak persists, check whether the radiator cap is properly fastened, then try pressurizing the system to identify the exact leakage point before determining the repair method; 3. Unscrew the engine oil filler cap to check for signs of oil emulsification—if present, dismantle the engine to replace the cylinder head gasket. A leaking radiator prevents the engine from receiving proper coolant circulation, which may cause overheating, cylinder seizure, or bearing failure resulting in startup failure. It also reduces oil viscosity and accelerates engine wear.
If you find the radiator leaking, don't rush to drive. Pull over and check the leak location. Last time I encountered this issue with my old Jetta, I opened the hood and found a loose hose connection. Tightening it temporarily with a wrench worked as a quick fix. If the radiator itself has cracks or corrosion, you should immediately go to a repair shop for a replacement. In case of severe coolant leakage on the road, an emergency solution is to pour a stop-leak agent into the radiator, but this only provides a temporary fix. Regularly check the coolant level, especially before winter when you must replace it with new antifreeze to prevent freezing and cracking the radiator. Last time, the mechanic mentioned that a water pump leak could be mistaken for a radiator issue, so it's best to have a professional diagnose the problem.
There are usually several signs of radiator leakage: fluctuating temperature gauge, green liquid under the car, or white smoke from the engine compartment. The most troublesome case I've dealt with was pinhole leakage at the bottom of the radiator, which was temporarily repaired with plastic steel putty to make it to the repair shop. Simple handling steps are: turn off the engine and wait for cooling → locate the leak → small holes can be sealed with sealant → large damage requires direct replacement of the radiator. Remember not to add tap water when there's a leak, as tap water can cause scaling and clog the pipes. It's best to check the radiator connecting pipes for aging and cracking every season, and rubber pipes should be replaced every three years.
