Cooling System Mistakes That Could Ruin Your Engine, by Budget Mechanic on YouTube. 12 min 13 s.
- Video length
- 12 min 13 s
- Time to do it
- 20 minutes
- Difficulty
- Easy
- Steps
- 10
What you need
Steps
Park on level ground and let the engine cool completely, at least 30 minutes. Never open the radiator cap or reservoir cap while the engine is hot.
Check the level in the plastic overflow bottle first. It should sit between the MIN and MAX marks when the engine is cold.
Look up the exact coolant specification in your owner's manual. Match the type your maker lists, not just the colour of the fluid.
Open the radiator cap or reservoir cap slowly. If you hear hissing or feel pressure, stop and wait until it is fully cool.
Pour premixed coolant in through a funnel, slowly, until it reaches the full mark. Filling too fast traps air in the system.
Do not fill the system from a garden hose. Tap water leaves minerals and scale inside the radiator and water pump.
Run the engine with the heater on full, let it idle until the fan cycles, then top up again once it cools. This burps out trapped air.
Skip stop-leak products unless you are stuck at the roadside. They can clog the radiator and heater core.
Watch the temperature gauge on your first drive. If it climbs above normal or the level keeps dropping, you have a leak to find.
If the coolant is brown or sludgy, drain and replace it fully instead of topping up. Follow your maker's service interval.
Tips and common mistakes
Never mix two coolant types, as the additives can react and form sludge.
Mix concentrate 50/50 with distilled water, or buy premixed coolant and use it straight.
Coolant is toxic and tastes sweet, so keep it away from children and pets and dispose of it at a recycling centre.
Do not overfill the reservoir past the MAX line, as the system needs room to expand.
Questions
Can I just top up with water?
Only in an emergency, and only enough to get you home. Plain water dilutes the antifreeze, lowers boil and freeze protection and adds rust. Drain and refill with the correct mix afterwards.
Which coolant should I buy?
Use the specification in your owner's manual. Modern cars often need a specific long-life formula, and colour alone is not a reliable guide because makers use different dyes.
Why does my coolant keep dropping?
A small loss over months is normal. A level that falls quickly points to a leak at a hose, the radiator, the water pump or the head gasket, so get it pressure tested.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
