Car radiator repair

Car radiator repair  — How to

Can you DIY a car radiator repair?

That depends on where the leak is. You can perform car radiator repair in the tanks, drain and radiator neck. You can sometimes fix a leaking radiator core. If your radiator is leaking in other areas, it must be replaced.

Let’s take a look at the components in a car radiator

Most common car radiator leaks and repairs

Car radiator repair in a tank

The plastic side tanks are made with a fiberglass impregnated nylon. These are difficult to patch, but not impossible. You’ll need a radiator repair kit that contains a compatible epoxy, a sheet of fiberglass cloth and some sandpaper.

Don’t even think of just applying epoxy to the crack or hole. It won’t last. The repair must be a patch.

Drain the radiator.
• Scuff the surface using sandpaper
• Clean the sanded surface using a solvent cleaner to remove grease and sandpaper residue.
• Mix the epoxy and apply the epoxy resin and cloth per the instructions in the kit.
• Allow time for the epoxy to cure before refilling.
• Start the engine, let it idle and then take it for a short test drive to make sure the patch holds. If it does, keep a gallon of coolant in the trunk in case it fails.

Fix a leak in a car radiator neck

A broken radiator overflow neck is a common problem. Don’t try to glue it back on. There’s an inexpensive fix. Buy a Dorman overflow repair kit

Fix a leak in a car radiator core

In the old days when the radiator core was made from copper you could have the leak resoldered. But you can’t do that with aluminum radiator cores. Try a radiator stop leak product designed for aluminum cores. Follow the directions and don’t add too much. More is NOT better.

Fix a leaking car radiator drain (petcock)

DIYers make the mistake of trying to drain their radiators by removing the plastic radiator drain. Due to its age, it often breaks as you remove it. Don’t bother trying to fix it. It’ll never hold.

©, 2022 Rick Muscoplat