I get a high pitched whistling sound when I first start the engine every day and after it has been parked for several hours, which lasts several minutes. It doesn't vary much w/RPM or car speed. Seems to be at passenger side front of engine. No obvious problems w/steering or charging. More noticeable since blazing hot TX heat started. Any thoughts are appreciated.
My '95 4.6 was doing that from around 2015-2016. I couldn't find it, thought it was temperature related. Now that you mention it, I don't think I've heard that noise since I cleaned out the EGR tube back in January.
Idler pulley. Try replacing the idler pulley or the belt tensioner that MCM51 mentioned. You'll probably also want to replace the belt.
If you can't trace it to a vacuum leak look at the pulleys.
#1 is the Idler pulley
#2 is the alternator
#3 is the other Idler shown on the right above
#4 is the Power Steering pump
#5 is the water pump
#6 is the crank
#7 is the tensioner pulley
#8 is the AC compressor
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Last edited by Trunk Monkey; 07-04-2017 at 08:36 AM.
Reason: ID Pulleys