How to Repair a Leaking Radiator

A Quick Auto Fix With Pepper!

Cooling system of a modern car, leak test
ollo / Getty Images

Some roadside emergencies require a call to a tow truck and a haul to the mechanic. Others can be temporarily solved with just a bit of preparation. For instance, fixing a leaking radiator is as simple as having a few packets of pepper on hand.

Drip Drip Drip

If your car begins hissing and steam erupts from under the hood, the first thing you should do is pull over. Then check under the car. If you spot coolant dripping out from underneath your car, you probably have a radiator leak.

What Now?

First, stay put. Many thousands of dollars are wasted on major engine repairs simply because the driver "tried to make it" someplace while the car was overheating. When coolant escapes from your radiator, your car's ability to stay cool goes with it. If your engine becomes too hot, it will start to distort, melt, and even break. That kind of damage can cause some very costly repairs. Replacing a radiator is far less expensive than replacing an engine. Before you do anything, wait about 15 minutes for your vehicle to cool off. Hot coolant could burn you.

Fix It With Pepper

If you notice that the coolant is gushing rather than dripping, or you can see a broken or split radiator hose, you should try a radiator hose emergency repair patch or some duct tape. But if you have a pinhole leak, which usually appears in the radiator itself, you can save the day by using the condiment that may even be in your vehicle already—ordinary table pepper.

Once your vehicle has cooled off, open the coolant filler cap and pour in as much pepper as you can find, up to a full shaker's worth is best. Start the car and let it warm up, allowing the pepper to circulate through your coolant system. With luck, the little pieces of pepper will find the pinhole and clog it right up, giving you a chance to get to the shop for a real fix. If all you've got are peppercorns, this will work, too.

Just know that this isn't a permanent solution. Not only is it unlikely to last long, you will eventually need to flush all that pepper out of your car's cooling system. Though the pepper probably won't cause any damage, it still shouldn't be floating around in your cooling system.

Scramble Some Eggs

Pepper is not the only quick fix for a radiator leak. On the off chance that you happen to have a few eggs on hand, the yolks can also serve as a temporary fix. Separate about three to four yolks from the whites, discard the whites, uncap the radiator, then pour the yolks inside. Start the engine and give it a few minutes. The eggs will soon congeal and fill the leak hole. But, again, this is a temporary solution that's meant to get you back on the road and to a repair shop. And talk about a mess—which is why you should only use it in an extreme emergency and if you are within only a few miles of a repair shop.

If you are worried about a radiator leak stopping you on the road, the best solution is to keep a small container of radiator sealant in the vehicle. It's a surefire way to make sure that you have what you need to temporarily seal a leaking radiator—without making scrambled eggs.