I have a 97 Ford F150 with a 4.2L engine. When the air temp is around
35 or below I get a very loud whistling coming from the engine. It occurs mainly between 1500 to 2000 rpm but varies with engine load and throttle position. It is so LOUD I can't tell exactly where it's coming from. Could it be a vacuum leak or bad air pump maybe? Any suggestions will be greatly appreciated as I am about to start wearing ear plugs. Thanks, jeff
Stop messing around and get you some ear plugs! ;)
When stuff is really loud like that, it over loads your ears. Put in some foam rubber ear plugs, wear them for awile and then try to isolate the source again, maybe using a cardboard tube or something.
Loud speakers can be rattling etc at high levels, put your fingers in your ears and get up real close to them and you can hear all kinds out-of-place noises in them you couldn't otherwise hear.
Alvin in AZ
The problem has been identified thanks to a mechanics suggestion and Divine inspiration. The mechanic thought that the whistling noise might be coming from one of the belt pulley bearings even though it only seemed to occur at a specific rpm. By chance I picked the alternator pulley and squirted a little WD40 behind it and the noise was gone! I'm now putting a couple of drops of heavier oil behind and hoping I caught it early enough to save the bearing. Jeff
Save the bearing long enough to make it more convenient for you- yeah, but make it last a few years- no, maybe not even weeks. :/
BTDT and had the bearing last only one more day on a VW generator, most others tho lasted for weeks and one time ('67 dart) lasted years but it was barily making noise when I caught it.
If you want to replace the bearing yourself go to a bearing shop for the best prices. Prob'ly a 6203 bearing.
Alvin in AZ
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