Autozone Coolant Cap (2024)

FAQs

What happens if coolant reservoir cap is bad? ›

When the radiator cap is bad, your car is likely to overheat, which can cause more serious issues down the line. Essentially, the radiator cap would no longer be able to correctly maintain the internal pressure of the system. Drastically increased pressure could cause certain parts of the cooling system to break.

After running the engine allow it to sit for at least 15-20 minutes before opening the radiator cap or the reservoir. The coolant reservoir tank is the fist place to check for a proper engine coolant level. This will be a clear or white tank located at the top of the engine bay.

Modern engines tend to require a higher-pressure cooling system compared to their earlier counterparts, which in turn require more effective sealing, i.e. a radiator cap. The absence of a radiator cap in your cooling system can result in some pretty sticky situations, such as: inefficient cooling. loss of coolant.

They will do very minor things if they aren't busy like change blinker bulb, install batteries, replace wiper blades, and a few things like that but they don't do any type of internal work like engine work or repairs. They might add coolant or stop leak to your radiator but they don't replace or repair parts.

Yes you can. In fact, if you develop a water leak it is wise to remove the rad cap and drive without it, just topping up with water every few miles.

Make sure your engine is off and cool, your vehicle is in Park or Neutral, and the parking brake is set. Locate the engine coolant reservoir; translucent white color, and has hose(s) connecting it to radiator. The reservoir has a fill range marked on the side.

A faulty radiator cap can result in engine overheating, loss of coolant or major engine damage. So, Pressurized cooling systems help prevent overheating and coolant loss. Also, It raises the coolant boiling point about 3-degrees F for each additional psi above atmospheric pressure.

“When the engine is cool, open your hood, and locate the coolant reservoir. The coolant level should be between the F(full) and L(low) marks on the side of the coolant reservoir.”

Conclusion: Never drive your car without coolant

If you discover that you are running low and there is no gas station nearby, then it is recommended that you should call for assistance. Do not continue to drive as you may end up permanently damaging your engine.

Without the cap, the steam bubbles push coolant out of the radiator neck in large “burps”. This lost coolant makes overheating worse and if not quickly shut off, the heads on the engine can warp, causing the head gaskets to leak.

Can I run car with coolant cap off? ›

Yes, you can start a car with the radiator cap off. In fact, turning the engine on with the cap off can help remove air bubbles which is part of the process when topping up your radiator coolant level.

Typically though it should be left to cool for 1-2 hours before it's cooled sufficiently to open the rad cap safely. If you're actually trying to check the coolant level then you probably need to wait more like 3-5 hours (as if the coolant is still warm it will show a falsely high reading due to expansion).

Long-term Engine Damage

In the long term, the engine will suffer from several problems. The most common issue is cracked cylinder heads. What happens if you overfill coolant? Overfilling coolant can cause it to leak out through these cracks, which can lead to overheating and damage that may not be reversible.

Turn on the engine with the radiator cap off so as to prevent pressure from building up. Let the engine run for about 10 to 15 minutes to let the coolant circulate freely inside the radiator and allow any trapped air to dissipate.

When your cap does not seal properly, air will get inside of the cooling system. This will cause air pockets to get inside of the heater core, thermostat, and radiator hoses. As a result, the engine will start to overheat because it cannot sustain a temperature that is consistent.

An essential part that's cleverer than it appears

The pressure builds up and suppresses the boiling of the coolant. Water can be taken to about 107°C at 4psi above atmospheric pressure and to 121°C at 15psi above. The cap regulates the maximum pressure, preventing damage to the hoses and radiator.

The most common sign of a bad coolant reservoir is a pool of coloured water beneath your car, or more specifically, the passenger's seat. We are not specifying the colour here, because there are different car coolant colours that serve different purposes.