2015 Express Passenger 3500 6.0l short wheelbase with about 40k miles on it. I heard a slight exhaust tick and looked when doing the last oil change. Sure enough the driver side rear bolt was missing it's head.



At some point I think I'll pull the manifolds off, extract the stud somehow (likely have to weld a nut to it because it looks flush with the head), and replace everything. For now I decided I'll just throw a clamp on it to keep it from getting any worse.

I picked up one of these knock-offs from China on Amazon with brackets for both sides just in case.
TEMSONE Exhaust Manifold Bolt Repair Kit Compatible with Newer GM Trucks And SUV 4.8 Liter 5.3 Liter 6.2 L 1999-2013, 6.0 L 1999-2021
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Quality looked ok. Fit was ok. A ground wire was attached to the head there. I installed the bracket with some copper anti-seize on the bolts and moved the ground wire to outside of the bracket. I put some red loctite on the bolt that pushes against the manifold. No more tick (that I don't think my wife could hear or notice but it bother me).



While I was in there I noticed a very weathered vacuum hose. The 7/32" hose that goes from the top of the intake manifold to the passenger side of the engine bay behind the AC receiver/drier. My wife was kind enough to go and pick some up. Needed 2ft but the first AutoZone was out so she had to drive to another.







The exhaust fix was very easy. It was harder to take the doghouse off than put the bracket on. The vacuum hose was simple even though under the hood side could only be done by feel because you can't see it. Simple project turned into a couple of hours from letting my son do some of the work and delay getting the vacuum hose.

 

thanks for all the photos

 

You're welcome. I figured this was a common issue that pictures would be helpful for and it's nice this website allows uploading pictures.

 

Will you say more about "slight exhaust tick"?

 

I could hear a slight slow tick. An exhaust manifold leak is sometimes hard to tell from a valve/lifter tick (at least for my amateur ear). They both happen once every other revolution of the engine so it isn't fast. It wasn't that loud either it was hard to hear over the noise of the engine fan (my wife couldn't hear it at all). Slow is relative because it was still happening multiple times a second at idle. I should have recorded it but wasn't thinking. When I saw the bolt head broken off on the same side of the engine I could hear the noise from I knew exactly what needed to be done. No more noise after the clamp.

 

@Triaged It seems that I'm going through many of the same things with my van as you are.

I have a similar tick when cold. Clearly from the passenger side. Haven't checked the bolt yet, will do so soon. I'm just assuming that this is the issue since it seems common. (also mentioned in this thread)

Reason I'm asking, though - you didn't happen to have any bad readings from an O2 sensor to go with it, did you?

I had a Bank 2 Sensor 2 below threshold error a few months back. At first I could clear it but then it wouldn't clear. The voltages were all over the place, so I replaced the sensor. Error went away for a while but it's back again. It always seems to show up if I let the van idle for a while (10 minutes or so) and then drive it without stopping and restarting the engine.

Wondering if this broken manifold bolt could be related. Hoping I don't have a bad cat.

 

I haven't had any codes...ever. it's still got low miles and stuff is just wearing because of age. I think I caught that broken stud before it burned a hole in the gasket. I need to replace it at some point. I already bought the parts but don't look forward to trying to weld inside the passenger compartment of the van.

Yes look for a leak from a broken bolt since it's so common. Have you looked at the wiring or thought about swapping sides on that sensor?

 

Mine is a 2016 with relatively low miles (61k) but I definitely haven't had that same luck with no codes. In addition to this emissions stuff I've had a bad yaw sensor as well.

 

So we are about in the same boat. I've got 52k on my 2015. Had to replace the radiator... I likely went too long in years on changing out the coolant. I need to do the transmission fluid now too. I did the rear diff when I put in a limited slip then again a few k later. I really should replace the brake fluid. I've now got a scan tool that will bleed the ABS. I've used a turkey baster to remove what was in the reservoir and topped up with clean a couple times on the brake fluid and power steering fluid. I figure having some new stuff in there is better than nothing until I do it right.

 

I've been really happy with this brake bleeder. It makes the job super easy and fast with just one person.