Just got back from a 1,000 mile round trip hauling my car hauler, and after parking the truck back home I noticed a more prominent whistle - which sounds like the turbo. When I rev the motor the whistle increases, and decreases typical of the turbo...its just much more noticeable. Kind of like the difference in going from stock air intake to the 6637 Filter, but now even more. I also noticed some greasy residue/soot by the CAC boot that wasn't there before. I think I need to spend the money and do a Riff Raff boot kit, but just curious if a failing boot/boost leak would also be a source of the more prominent turbo whistle? Other than that the truck still towed just fine, even up the hills.

 

The correct flow through an orifice (hole, crack. split, etc.) will resonate (make noise). That being said, if your boots are just leaking by I wouldn't think it would be aurally noticeable IMO. Have you noticed if your boost levels are the same or have they dropped since the noise started?

 

I did not notice any difference in boost or power during the drive. All seemed fine there and back.

 

Just spitballing but a noise that large seems more pre-turbo. Have you inspected the intake including the filter for any loose/bad connections or possibly a damaged filter? If you aren't noticing any boost leaks that's about the last thing I can think of that would make a difference in the noise.

I've had buildup on my CAC pipes around the boots for some time. I'm not sure how much is old or how much is new but I don't seem to have any boost leaks from them or any increased noise. I do occassionally check the clamps for tightness as I have noticed that mine loosen over time.

 

Not saying I don't have a boost leak, I just can't confirm that I do based on my limited use of the truck. When I stuck my head in the engine compartment, the noise seemed to be coming from the turbo area, not the filter. The noticeable build-up on the CAC pipes (which is fairly new) is what lead me to my conclusion. I'll check the filter/intake and clamps on all the factory boots. But at 175k miles it may be good insurance to replace the stock boots?

 

You can but IMO unless you really suspect them I wouldn't with the original turbo. Once you start getting into wheels and wastegate controller mods then it would be good insurance against blowing a boot on the road.

As the miles climb you get into the "insurance" mindset. I know I have. You can only anticipate so much before it becomes cost prohibitive to keep replacing things that aren't failing or broken. I've reached a compromise where I'll go whole hog (or as much as I can afford at the time) if I'm diving into something to do everything I can while stuff is out but that's just me. For example when I had a HPO leak I rebuilt the HPOP, got new HPO and fuel lines, re-sealed my fuel bowl, installed an FRx, and deleted my HPX. Some of that wasn't failing but since I had the area opened up I did some preventive/upgrade work.

Stuff I can get to (like CAC boots) I'd use them until I had a problem or did something that called them into question since you're not hitting any excessive pressures. Just my .02