This is a California truck. The whine sometimes continues for about 15-45 mins. Mostly during cold weather. I've listened with an open hood, and it seems to be near the "smog pump." Very hard to tell the location.
Any help?
John
Its probally the smog pump.
john opined in news: snipped-for-privacy@uni-berlin.de:
had same on 85 e150 351, just before pump locked up
The air pump probably has a diverter valve that dumps the air into the engine compartment until the engine is up to temp so that the catalyst will work. This unmuffled air will have a high pitched sound due to the vane pump.
The alternator will be charging heavily the first few minutes after starting, and will make more whine than usual.
And the power steering pump will make more noise than usual with cold, thick fluid.
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