Jeep Wrangler Radiator Overflow Tank Head Scratchers
The overflow tank, also commonly referred to as an expansion tank, a coolant reservoir or an overflow canister, is an essential part of the Jeep Wrangler's cooling system regardless of what you call it. It is connected to an overflow tube that comes from the radiator to provide extra storage space for the coolant as it expands when the engine heats up. Without this extra overflow storage space, the coolant would expand and may damage the tubes and may cause leaks. Any problem connected with this could compromise the overall functionality of your engine. Therefore, being equipped with firsthand knowledge about problems that may emanate from a bad overflow tank is a must.
Changes with the temperature
If you notice that your vehicle is having a variation with its temperatures even though nothing serious has changed in your car, then there might be a problem with your overflow tank. This is usually communicated through bubbles within the storage. However, this isn't a conclusive sign of damage. At certain times, this could be more of an indicator of problems with other parts. Be sure to investigate the totality of the engine cooling system as it could lead to more issues indicative of the main problem.
In the next paragraphs, the bubbling in the radiator overflow tank will be decoded between being normal and being problematic. First, the normal bubbles. Finding a few bubbles is common in the overflow tank. One of the functions of the overflow tank is to actually remove the bubbles caused by the air expanding in the cooling system. Coolants work much more efficiently without air bubbles because the air bubbles interfere with the coolants' ability to absorb heat at a fast rate. Making the coolant more efficient means the engine will be less prone from overheating.
Bad news bubbles
The bad side of bubbles in the overflow tank could also be the sign of a leak within the tank or along the cooling system. This is reflected by the presence of too many bubbles even if the car is already cold. Inspect everything thoroughly as it may be a leak in critical areas like the head gasket. Once that blows off, the engine will be useless.