New to the forum here. I test drove a 2016 Platinum trim with the 3.5 EB engine. The truck has high miles (169,000) but the price is right so I stopped in to see how it rides. Start up sounds good. Shifts smooth through all gears. Suspension felt good. The only thing I noticed was while coasting on the highway my, if I accelerated hard I would get good power and then a quick whoosh sound, similar to a burst of air, from what seemed like it was under the truck and not the engine compartment. Forgive me if this is something obvious like a pressure release valve or something for the turbos. I’m new to the V6 twin turbo world. Is this noise normal or red flag?

thanks

 

I have a 2020 3.5, I never get a 'swoosh' sound as you explained, I would say not normal.

 

No whoosh sound from my EcoBoost. Sounds like some sort of issue with the TCBV (TurboCharger Bypass Valve). The discharge tube can get blown off or the gray plastic retainer can break. Some people actually intentionally remove the tube so their truck sounds like a turbo'd "rice burner".

Here is a picture of the discharge tube where it connects to the TCBV:

 

Thanks for the input so far. I’ve looked a little further and have found after market blow off valves that seem to engage similarly to what I drove. The big difference is the ones I see are on YouTube are much louder.

Now I’m curious if a previous owner may have put that on I guess to relieve back pressure to the turbo??

Let me know if that makes any sense…I’ll keep researching and check out what 52Merc suggested.

 

If the price is right and there are no problems I would go buy that truck in the morning. Trucks like that don’t last long. Good luck and let us know how it goes.

 

I’m going to go back tomorrow and take a look at the Intercooler. I should be able to determine if it has a bypass valve like 52Merc mentioned or if someone added a blowoff valve or even a hybrid possibly. I’m optimistic that if it was a bad bypass valve, there would be some other red flags like thrown signals, lack of power or response time. Thanks again for the input, I’ll let you know what I find out.

 

Was the whoosh while you were still WOT, or after you let off?

If its after you let off then the blowoff valve is probably working correctly but as 52merc noted, maybe the recirculation hose is not attached so you are hearing the air release.

If it is under steady boost pressure then it may be a different issue like leaking charge piping.