Exhaust leak sound 2016 Suburban

[Prospect62]

Hey guys,

I've noticed that my truck has developed kind of an exhaust leak "ffft ffft ffft ffft ffft" sound on cold startup. It disappears within about a minute of warmup. It's coming from the driver's side undercarriage. I haven't gotten under the truck to look around yet.

I say "developed" - come to think of it, it may have always been there and I just didn't notice it. It's a 2016 with 66,000 miles on it - I've owned it for four months and put about 1500 miles on it.

Just wondering if anyone else may have had this issue. I'd hate to think it's exhaust manifold gaskets ALREADY but it's certainly consistent with exhaust manifold gasket failures I've had on other vehicles. I also thought about blaming the infamous "flapper" valve and/or some OEM band clamp (great idea) between the driver's side exhaust manifold and the cat.

Any info would be super. Thanks!

 

[Tiredmechanic23]

Has the vacuum pump been replaced under recall yet? If not it could be starting to go. I had a similar noise just after warranty way before the recall that was the vacuum pump.

 

[BG1988]

Hey guys,

I've noticed that my truck has developed kind of an exhaust leak "ffft ffft ffft ffft ffft" sound on cold startup. It disappears within about a minute of warmup. It's coming from the driver's side undercarriage. I haven't gotten under the truck to look around yet.

I say "developed" - come to think of it, it may have always been there and I just didn't notice it. It's a 2016 with 66,000 miles on it - I've owned it for four months and put about 1500 miles on it.

Just wondering if anyone else may have had this issue. I'd hate to think it's exhaust manifold gaskets ALREADY but it's certainly consistent with exhaust manifold gasket failures I've had on other vehicles. I also thought about blaming the infamous "flapper" valve and/or some OEM band clamp (great idea) between the driver's side exhaust manifold and the cat.

Any info would be super. Thanks!

emissions equipment has 8year 80k warranty

 

[Prospect62]

Welp I found the source of the leak and thank GOD it's not an exhaust manifold. There is a small clamp right before that weird flex joint thing and it's corroded and rusting out. There's a pretty substantial and growing leak there. Guess I gotta have someone cut and weld it up!

 

[Prospect62]

 

[Prospect62]

There is a TSB for this issue, GM# PIP5442 issued November 2016, in case anyone else has a similar issue.

https://static.nhtsa.gov/odi/tsbs/2016/MC-10114829-9999.pdf

 

[kentman]

I will have to keep an eye on this. I just had the vacuum pump done under the 150K mile warranty.

I see exhaust being an issue in the future. I will check for this leak.

I am looking for options on good cat-back systems. I am thinking Magnaflow.