How to Find and Fix Leaky Radiator Hoses on Trucks

Finding and Fixing Leaky Radiator Hoses on Trucks


Radiator hoses are an integral part of your cooling system and are critical to maintaining proper engine temperatures. Your hoses help move coolant between the water pump, radiator, and engine and any leak that develops will need to be dealt with promptly.

Checking and changing hoses is not a difficult process in most cases, and many hoses are clearly visible and easy to get to and replace. That said, there are hoses that are very difficult to change, and some have special clamps or connectors that may require special tools to remove. At times, it may be best to have a professional truck repair facility or a radiator repair shop service your truck. The cost of having a repair shop replace a difficult hose is relatively affordable when compared to neglecting that hose and then breaking down on the road.

Signs of a Leak

Your first sign of a leak could be the smell of antifreeze, a gauge showing a rise in temperature or a warning light. You might see antifreeze on the ground or steam from under the hood or inside the cab from a heater leak. Maybe you no longer get heat because your fluid is low creating an air pocket in your heater core.

If you have to keep adding fluid but find no visible leak, you might have a cracked engine or bad head gasket venting fluid out the exhaust. Maybe it is a bad radiator cap losing fluid as you drive. In any case, if you are losing fluid from an unknown location you will have to get your truck in for service.


While inspecting your hoses, be aware that there are more than the two main radiator hoses that you will need to check. You have heater hoses, overflow and reservoir hoses; there could be a by-pass hose and some radiators have more than two hoses running to them. Make sure you know how many coolant hoses your system has, where they are and check them all. Also, make sure all your clamps are tight but not cutting into the hose.

Things to look for when checking hoses;

  • Rub or wear marks
  • Soft spots or hardened hose material
  • Bulging, swelling or inflated hoses
  • Cracks along the hose or tearing at the clamp
  • Worn or corroded clamps
  • Dampness or fluid under the hose or clamps

Hoses are wear components and will weaken and fail. You will need to check and replace all your hoses on a schedule no matter how good they look or how well they seem to be working. To help avoid problems, visually check your hoses during oil changes or any engine service and replace them as needed or at recommended intervals.

Always double check the top radiator hose coming off the thermostat and going to the radiator. This hose carries the most heat in your cooling system and will usually fail the fastest. Also, check its connection to the radiator for leaks and if you have a plastic tank radiator check the back of the tank behind the top hose connection for heat caused stress cracks.

If you can’t find a leak, you need to perform a thorough system check that will require using a pressure tester. A pressure tester will pump air into the cooling system building up the appropriate operating pressures, exposing any leaks that may not show up without the added pressure. Take the time to check your radiator cap also and make sure it is holding and releasing pressure at the proper points.

While you should never open a hot cooling system, a hot system may show a leak where a cold system may not. In cases like this, you should always have a certified truck repair shop check your system while it is at operating temperature and under pressure.

Below is a video showing how to perform a basic hose check for a car, and the process will be much the same for your truck.

Fixing a Radiator Hose Leak

There are a few things you can actually do to allow you to fix a radiator hose leak. All three hose repair options are temporary, short-term fixes and should be replaced with a new hose as soon as possible.

  1. Carry some duct tape and rubber cement with you. If you develop a leak, you will need to clean the area of the leak, removing all dirt, fluid and oil. You should then scuff up the area a little. Put some rubber cement in the hole and on the hose, securely duck tape the area and get to a service facility as soon as possible. This procedure would be similar to fixing a tire or inner tube and adding duct tape for strength.
  2. Buy or make a hose splice kit. The kit should have 4 to 5 inch plastic or metal piping that will tightly fit into the 3 or 4 different hose sizes on your vehicle. Make sure you have all the clamps in the sizes you will need to secure these splices. If a leak develops cut your hose right on the leak, insert the fitting and securely clamp it all together. If the leak is at the end of the hose just insert the splice in an accessible area, cut off the bad end, and now it will still be long enough to reach.
  3. The best idea is to keep all hoses and belts when replaced. When you replace a worn belt or old hose just clean it, bag it and put it in your vehicle for an emergency. Don’t toss these things out! Old working parts do not belong in the garbage. Keep a spare if it’s just old and worn but still good. So do your proper maintenance, change your hoses and belts and store everything away for an emergency, you’ll be glad you did.

Average Cost of Repairs

The average cost of replacing a simple truck hose would normally range between $75 to $250. But the problem with giving any cost estimate is the wide range of factors involved.  Do you also need a system flush? Do you need all new antifreeze? What type of antifreeze? Is the hose easy to replace? Who is doing the work? Are you using OEM hoses, aftermarket hoses, hoses with O-rings, generic hoses, name brand hoses or green hoses? To say the least, you need to check the costs for your specific vehicle. You also need to check prices from different suppliers so make some calls.  A true cost estimate will depend on a lot of factors. Whatever the cost, it will be a lot less than the cost of breaking down on the road.

If you should break down on the road, here are a few options to help getting you up and running again: