What's The Whistle

[GMCanuck]

So I noticed this for the first time after towing our travel trailer about 150 miles...

 

When we arrived at our campsite and went to back the trailer up, I noticed a high-pitched "whistle" from under the truck. Pitch changed with increased throttle. Sounded a bit like some form of exhaust leak, but I am not familiar with what would cause this type of noise.

 

Next day, everything was back to normal - until we pulled the trailer home a few days later, and when we got home, the sound was back.

 

So, it seems as if this is related working the truck harder - by towing the trailer. The trailer is about 7000 lbs, and I drive in "3" (not OD), no faster than about 60mph.

 

Any thoughts?

[az'03Silverado]

The only thing I can think of is a vacuum leak. Try checking all of the connections.

[music]

Do you have e-fans? I ask, because both of mine run almost constantly after towing the camper (~7k lbs loaded) for a while, until the engine is shut off. There's no "whistle" on mine, but it may be air blowing over something?

[GMCanuck]

The only thing I can think of is a vacuum leak. Try checking all of the connections.

 

That sounds like a possibility, but are there any connections under the truck? The sound definitely seems to be coming from underneath - not the engine bay.

[GMCanuck]

Do you have e-fans? I ask, because both of mine run almost constantly after towing the camper (~7k lbs loaded) for a while, until the engine is shut off. There's no "whistle" on mine, but it may be air blowing over something?

 

Yes, I have e-fans and I can certainly consider this, but again, the noise seems to be loudest under the truck - back from the engine compartment.

[pm26]

Is this possibly power steering pump whining noise? It is very common on these trucks and it comes an goes. My truck does it sometimes for no apparent reason, then it goes away for a while.

[MYZ-71]

sounds can travel and really surprise you, just a guess but I had a similiar issue with mine and it turned out to be the a/c belt tensioner pulley bearings.

[az'03Silverado]

Maybe it's the turbo you didn't know you had?

[ChevyTech77]

Exhaust leak.

 

Curious though, what does the camper that you're pulling weigh, loaded and going down the road?

[GMCanuck]

Exhaust leak.

 

Yeah, that's what I was thinking. But why just after pulling? Increased pressures inside the exhaust system at higher revs/load maybe?

 

Curious though, what does the camper that you're pulling weigh, loaded and going down the road?

 

Haven't put the trailer on an actual scale, but the GVWR is 7500 lbs. Any more and I'd be looking for an HD...