2004 -F150- 5.4- HIGH PITCH WHISTLE

Does it only happen when the engine is cool, or also when warm? Have you tried letting the truck warm up first before driving? (just trying to get some info here). My first instinct would be to replace the belts, I don’t think those 5.4’s had timing belts (I think, like any good engine, they have chains instead). I’d go for the accessory belt first – cheap, easy fix. Also, when you replace it (if you do it yourself – if you take it to a shop, don’t go to jiffylube, find a place that has a half-decent mechanic, even midas, NTB, and other exhaust shops usually do a decent check of the vehicle and hire better mechanics generally) check your pulleys for any signs of damage.

By the way – this isn’t the SVT, right? Right?

Thoughts are just the usual, many issues tend to crop up during either the super-hot days in the summer or unusually cold ones during the winter and fall (in areas that get these wide variations).

Rubber grommets, seals, bushings, belts, etc all tend to get audible issues during the cold months, as they may have already had cracking, or just otherwise have an issue, and this just makes it more apparent. Most times in my opinion this is actually good fortune, as you state, it’s only an annoyance, not actually causing any noticeable problem yet.

You’d need to pinpoint the location of the noise. Just a rolled up newspaper, a mechanic’s stethoscope, etc will do if it’s not obvious to you right away.

It may also be a characteristic of the vehicle. Some intake tube designs can cause noise like that. The often put ‘mufflers’ in the hose to help prevent these but I have see some vehicles that just make the noise no matter what. Keep us posted if you find a solution to this.