How to Diagnose a Cooling System Problem

Photo:Attribution Some rights reserved by crudmucosa

Visually Inspecting Your Coolant System

  1. Allow the engine to cool.Your engine bay gets extremely hot while the engine is running, so poking around the engine bay before it has a chance to cool can result in serious burns. Allow the engine to cool for a few hours before opening the hood and looking for evidence of a coolant leak.

    • If the hood still feels warm, the engine inside is likely very hot.
    • If your vehicle has been overheating, it will take even longer for it to cool enough to be safe to touch.
  2. Put on the appropriate safety gear.Before starting any automotive project, you should put on the appropriate safety gear. Because you’ll be dealing with coolant that may be leaking, eye protection should be considered mandatory for this project. Gloves are optional, but may protect your hands from scratches or bumps as you work.

    • Always wear eye protection when dealing with coolant leaks, as they may drip or spray under pressure.
    • Glasses or goggles are both acceptable forms of eye protection for this project.
  3. Check the radiator cap for damage.Another common point of failure in coolant systems is the radiator cap. When functioning properly, the radiator cap can release excess pressure that builds up in your coolant system, but over time it can become worn out or stuck. If the radiator cap looks rusty, is corroded or caked in grime, it may be the cause of your coolant issues. Replace your radiator cap simply by unscrewing it and screwing in a replacement.

    • Radiator caps are inexpensive and can usually be purchased at your local auto parts store.
    • Never remove the radiator cap from an engine that is still warm. It could spray hot coolant and burn you.
  4. Visually inspect the water pump if you can.The water pump in your vehicle pumps the water and coolant mixture through the engine and into the radiator where air flow helps to dissipate the heat. Look for signs that your water pump is leaking or has failed if it is visible in your engine bay. The water pump is belt driven, so inspect the belt for damage that indicates that the water pump pulley has stopped moving and has been rubbing against the belt.

    • Without a properly functioning water pump, your engine will not be able to dissipate the heat it produces as it runs, causing the vehicle to overheat.
    • If the belt powering the water pump is damaged, it will have to be replaced after you put in a new water pump.
    • If you are unsure of where to locate the water pump in your vehicle, refer to its service manual or the website for the auto maker.
  5. Assess damage to your coolant hoses.Look at the hoses traveling from the radiator and to the engine, then follow them along for as far as you can. If any of the hoses are kinked, that will cause the coolant system to fail to function properly. Cracks may also indicate a leak, but even if it isn’t leaking yet, a cracked coolant hose should be replaced before it begins to leak. Keep an eye out for damage to the hoses or signs of rubbing from the serpentine or accessory belts.

    • If one of the belts has been rubbing on a coolant line, they will both likely need to be replaced. Make sure to install the new ones with enough clearance to avoid rubbing the belt on the hose.
    • Leaks in your coolant can result in puddles beneath your vehicle and overheating.
    • Replace radiator hoses that are leaking or are otherwise damaged.

Article provided by wikiHow, a wiki that is building the world’s largest and highest quality how-to manual. Please edit this article and find author credits at the original wikiHow article on How to Diagnose a Cooling System Problem. Content on wikiHow can be shared under a Creative Commons License.

Share in...

    You must be logged in to post a comment Login