How to open radiator cap when hot?

Along the way, engine overheats might happen to your car, primarily if your car cooling system is not maintained correctly.

When overheats happen, a common step is to check the condition of the radiator coolant. Most people will open the radiator cap directly to check the radiator coolant water.

Even though, there are other safer ways, by paying attention to the level of the radiator coolant through the radiator tank reservoir tube. There are maximum and minimum marks on the reservoir tank tube to check the radiator water level position safely.

However, if the coolant in the reservoir tank is empty, the coolant water inside the engine cooling system will also reduce. You inevitably feel the need to open the radiator cap.

Before you open the radiator cap when the engine is hot, you should pay attention to the things below.

Precaution before opening the radiator cap when the engine is hot.

1. It's best to let the engine cool down before opening the radiator cap (1-2 hours).
2. Get an oversized, thicker washcloth to avoid a burst of radiator coolant.
3. When the engine is overheated, water pressure and hot steam inside the radiator can gush out and injure us if we are careless and rushed when opening the radiator cap.
4. The radiator head (where the radiator cap installs) is design with two-step safety. Pay attention to the image below.

• Position 1 is the position of the radiator cap fully closed and remains locked.
• Position 2 is the position of the radiator cap to open halfway, but the cap remains locked.
• Position 3 is where the radiator cap can be fully opened and can remove from the radiator.

So, when going to remove the radiator cap, pay attention to these positions. Read more about the function and how the radiator cap works.

Also read:

• How does a radiator cap work?
• 5 symptoms of a bad radiator cap
• How to test a radiator cap?

If you need to open the radiator cap immediately, here are safety tips when opening the radiator cap when the engine is hot. Here are the steps.

How to open the radiator cap when the engine is hot

1. Open and remove the hose leading to the Reservoir Tank, then direct the hose to a safe area because it will use to release steam and hot water jets from the radiator.
2. Use a thick and wide cloth, then turn the radiator cap a LITTLE to the left, right at Position 2. In position 2, steam and hot water can flow to the reservoir tank through the hose.
3. Let the hot steam and jets of water flow through the reservoir tank's hose until the steam and spray are entirely discharged and gone.
4. Once it is safe (the hot steam is gone), continue by turning the radiator cap towards position 3 until it is completely open and we can detach the radiator cap.