Two years ago I had bad cracks in my coolant expansion bottle, so bad that coolant would leak though. I replaced the expansion bottle and after only two years there are already cracks showing. Not as bad as before, it’s not leaking yet however I believe this could still be a problem as the cracks are above the coolant level and it may be releasing air pressure.

My underline questions are should I change it again just to be safe and what are the effects on my engine if I ignore it? Does having pressure in the cooling system really matter? And most importantly can my engine over heat without my knowing.

1 Answer 1


Yes please change it whether it is a bike or a car. I am just saying with my limited knowledge of owning a car and a bike. For both of them i have found is the two things most important for an engine, the oil and the cooling system, to keep the pistons working and giving the engine a longer life.

For the pressure part, please read the below link. Its about the radiator cap but will tell you how the heat of the engine causes the coolant to expand thus building the pressure on the radiator cap. If there is a crack in the system, the coolant will leak even if you think the crack is above the coolant level. The coolant will rise to that crack level and leak. Also if the coolant container is cracking make sure the radiator cap pressure is the right one. Also coolant should not be filled till the top of the cap, some place has to be kept for the expansion of the coolant.


Engine will definitely overheat but you will know it from the indicator on the dashboard If the indicators are not working, the engine might stall in the newer vehicles since the ECU unit will get data from sensors on the overheat and switch the engine off.

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