1998 Mitsubishi Eclipse. 2.0L 5-speed. 195,000. When I complete my 33 mile trip home and shut off engine, I can hear air bubbling into the overflow tank from radiator. Temp gauge shows normal. Just had new water pump, thermostat, radiator flush and refill and new 16 lb radiator cap installed. Overflow tank fills up to near top (not running over) and when engine cools, the tank is back down to half way. I’ve checked water level in radiator when cool and it is full. Question: Is this normal? Don’t think I’ve ever noticed or heard the bubbling sound before. The engine runs great and smoothly.
Please Tell Why You Decided To Replace The Cooling System Prior To This Problem.
CSA
Two thoughts
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Was the air bleed out of the cooling system?
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Was the radiator cap replaced? It sounds like the cap is not holding pressure.
Ed B.
Had timing belt replaced and they usually replace the water pump and tensioners while they have it down.
Repairs were done by a NAPA sponsored garage and the mechanic had just finished the same repairs on an Eclipse a couple of weeks before so I thought he would be likely to remember. The radiator cap was replaced with a 16lb cap with the releif lever.
That isn’t a good sign. There may be a headgasket problem. Compressed gases can leak into the coolant when the headgasket seal fails. I suggest you have the coolant checked for exhaust gases to see if that may be the case.