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Old 10-18-2012, 08:14 AM
Larrick Larrick is offline
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Location: Berkeley California
Join Date: Sep 2009
Posts: 1,140
Mein Auto: 1994 525it
Yes there were bits of the old impeller in the box of parts which the shop gave me. I did not do the job.
I did not have the time and my son needed his car back immediately for work.
The system has been flushed so I assume the rest if the bits are out.
In diagnosing an overheating problem, could you assume:
If the upper hose gets hot when the engine is at operating temperature then the thermostat is working.
If the engine overheats with a good thermostat, that means a bad water pump.
But mine did not over heat at idle and the outside temperature was not cool and it could idle for hours.
It only overheated under load and when moving.
Since it did not overheat at idle, the fan was doing a good cooling job.
The fan is not needed at speed.
The question is, does an engine operate at higher temperature when at idle or at speed.
I would have thought that a bad water pump would have made it overheat at idle faster that at speed.
But it was the opposite.
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