When Do I Replace The Radiator Overflow Tank?
Radiator overflow tanks, also known as radiator overflow bottles or coolant reservoir tanks, can become discoloured, brittle, contaminated with sludge or even break with wear and tear damage. A damaged tank needs to be replaced immediately to ensure the effectiveness of your vehicle’s cooling system.
The coolant overflow tank captures the expanding coolant when the temperature and pressure in the radiator rises. Coolant will then return to the radiator when the temperature decreases. The vehicle cooling system can fail if a damaged expansion tank or bottle is not replaced.
How We Can Help
Coolant Overflow Tanks
Find the right coolant tank for your vehicle by using our fitment guide that includes a wide range of popular makes and models.
FIND YOUR NEAREST WORKSHOP
Enter your postcode below to locate the Natrad store near you.
- Can I install a replacement coolant reservoir tank myself?
If you have basic mechanical knowledge, installing a new tank is a fairly straightforward procedure. However, you need to be aware that many newer trucks, cars and SUVs require priming the coolant system according to the manufacturer’s instructions to prevent bubbles or air pockets forming.
A Natrad technician can help you select a replacement coolant tank for your vehicle with the correct fittings, and they can install the new tank for you if required.
- When does the coolant reservoir tank need replacing?
Signs that a radiator expansion tank needs to be replaced include:
- Coolant is always low
- Coolant is leaking, resulting in steam, puddles, drips and a detectable odour
- Your car engine is overheating.
Prompt replacement of a faulty coolant expansion tank will save potentially expensive consequences of engine overheating. A Natrad technician can diagnose the source of the cooling problem and recommend the best solution.
- How much coolant should be in the coolant overflow tank?
The coolant overflow tank should never be totally full. Check the coolant level when the vehicle is cold. If the coolant level sits between the maximum and minimum level marks, there’s no need to add further coolant. If the coolant level is below the minimum level, top up the coolant using a mixture of the correct coolant for your vehicle and distilled water.
A Natrad specialist can help you to find the right coolant for your vehicle. If you think you have a coolant leak, have your vehicle checked by a technician to determine the cause of the leak.
- What happens if I overfill the radiator expansion tank?
If the coolant level is just a bit too high, the excess will be gradually lost through evaporation. If the coolant expansion reservoir tank is too full, it will overflow through the reservoir overflow tube when the engine heats up. Once the level drops enough, it will still be high but will no longer overflow.
If you do notice that the coolant expansion tank overflows after being overfilled, check the coolant level again once the car has cooled to make sure that the coolant level hasn’t dropped too low.
Got any questions about our heating and cooling services?
Ask us, and we'll get back to you soon.