Engine whistling noise - 2016 Coachmen Sportscoach Cross Country 404RB

[VictorG]

Hello Everyone,
RE: 2016 Coachmen Sportscoach Cross Country 404RB - 64k miles / ISB 6.7L

I have an annoying whistling sound from my engine near the exhaust header, or maybe turbo boost or AC compressor. At idle it can make no noise, or slight noise or loud nose. Rev the engine and it produces loud whistling noise. Most recently while driving in Florida I noticed a reduction in power. So, I got to work troubleshooting. I looked at the header and I can see 4 of the exhaust ports and they look fine, that is to say I don't see soot around the connections between the header and the block. Can't see the outer ones as one is hiding behind the turbocharge and the other behind the AC compressor. I also checked the boots on the turbo intake, they seem fine. I'm also wondering if the AC compressor can make this noise. My wife said she read about someone saying one of the ports was whistling on his AC. Not sure about that. My only idea at this time is to get a mobile mechanic or take it to a shop and diagnose it. But taking it in will be fairly inconvenient. I'm fairly handy if anyone has a suggestion. Any thoughts?

 

[VictorG]

Correction....

Sorry, I mean manifold, not header. I wish I had performance headers on my RV!

 

[DogMan635]

Could it possibly be a "Spark Plug" popped out? Before you laugh, I recall years ago we had been working on a GAS truck, changing points and plugs. When you start putting the plug back in you do them first by hand to make sure there incorrectly. Sometimes, you may do all 8 sparkplugs by hand and then sit each with a socket wrench. I once forgot to sit a sparkplug and it came out. It made a "whistling Noise" but I was lucky as the plug wire was still holding it.

Just a Thought of a possibility along with MUD tires? or a sticking carburetor intake is stuck half open?

Just some ideas.....

 

[MGD1961]

Hello Everyone,
RE: 2016 Coachmen Sportscoach Cross Country 404RB - 64k miles / ISB 6.7L

I have an annoying whistling sound from my engine near the exhaust header, or maybe turbo boost or AC compressor. At idle it can make no noise, or slight noise or loud nose. Rev the engine and it produces loud whistling noise. Most recently while driving in Florida I noticed a reduction in power. So, I got to work troubleshooting. I looked at the header and I can see 4 of the exhaust ports and they look fine, that is to say I don't see soot around the connections between the header and the block. Can't see the outer ones as one is hiding behind the turbocharge and the other behind the AC compressor. I also checked the boots on the turbo intake, they seem fine. I'm also wondering if the AC compressor can make this noise. My wife said she read about someone saying one of the ports was whistling on his AC. Not sure about that. My only idea at this time is to get a mobile mechanic or take it to a shop and diagnose it. But taking it in will be fairly inconvenient. I'm fairly handy if anyone has a suggestion. Any thoughts?

You mention a reduction in power. Could be a vacuum or intake air leak.

 

[TitanMike]

A steady whistling noise on a turbocharged engine?

My first thought would be air leak between turbo discharge and intake manifold (pressure side).

My experience with exhaust manifold leaks has been a popping/"ticking" noise in time with cylinder firing. Same for loose spark plugs.

Coupled with loss of power would point me to the turbo and leak on pressure side hose or perhaps waste gate.

Whistling can also be mistaken for bearing noise in a turbo.

 

[Oaklevel]

I was thinking an issue with the turbo as well.