After some plumbing work on our M25, we refilled the coolant. We then went through the burping procedure, including hand-pumping coolant through the hot water heater. We also pressure-tested the system with the loaner tool from the auto store. Now the engine consistently overheats, but only at idle speed. If we increase the engine speed, the temperature stays around 160F, and continuously produces a stream of bubbles in the expansion tank. This has been going on long enough that I don't think it is just working an air bubble out of the system. The only other new symptom is an occasional screech, possibly the belt slipping (maybe we need to tighten it a bit, but it doesn't seem too loose) or perhaps a bearing in the coolant pump?
Does this sound like a coolant pump that is going bad and struggling to maintain sufficient flow at low rpm, or is there something else to check? Any thoughts would be appreciated--thanks in advance.
Erik
Does this sound like a coolant pump that is going bad and struggling to maintain sufficient flow at low rpm, or is there something else to check? Any thoughts would be appreciated--thanks in advance.
Erik