Exhaust/manifold rattle on ext. warranty?

[thebrakeman]

I have Ford's PremiumCare warranty, 7 years, 100,000 miles. 7 years hits in November on our 2006, which we have owned for about 2 years. So I have a short list of items to get fixed, all at once, to get the most of the $100 deductible.

My questions is an exhaust rattle. It's always been there (since we've owned) and always annoyed me. But since nothing else has deserved using the warranty, I haven't looked into it, beyond poking around myself, and having shops poke around while already in there. But since I'm taking it in now, I want to be prepared, and know the right questions to ask.

I know that squeaks/rattle themselves are not covered. But if the rattle is caused by some component failure, it would be. That makes me wonder if this could be any of the manifold issues I've heard of on this site. My symptom is a moderate rattle at around 3000 rpm while in motion. Does not rattle in Park just by revving the engine.

Any suggestions? My fear is that when taken to the dealer, they will charge for diagnosing. When they find no failed component, and can't find the problem, I'll be out the fee, and still have the rattle.

 

[thebrakeman]

OK, let's shorten that up a bit to get some replies:

What are some symptoms that might tell me a have a problem with manifold gasket, bolts, or other? Could my rattle sound be a manifold issue?

 

[Town]

An exhaust manifold leak is not usually characterised by a rattle, and at 3,000 rpm is perhaps more unlikely unless the manifold or the exhaust system is very loose. A rattle is more likely due to a loose heat shield especially around the CATs. A second area is the baffles inside the muffler, where a weld may fail and cause the baffle to rattle.

The Explorer has a single muffler assembly as standard, but a factory service replacement is two pieces. My son's 2007 Explorer EB 4.6 V8 has the two part muffler (Looks like 2 large cans). This may be due to the original muffler failing with a loose baffle but we don't know. I would not expect any part of the stainless steel exhaust to fail from rust within this 6 year time frame.

Another check is the rubber mounting doughnuts that secure the exhaust system to the frame mounting points. Any failure of these rubber parts may allow the exhaust to vibrate excessively and cause a noise when hitting small parts. At 3,000 rpm this may be a sympathetic harmonic vibration from the exhaust gas pulse frequency - that could be violent.

The exhaust manifold leak is characterised by a very noticeable noise when cold that quietens a bit as the parts warm up. The escaping gas causes the noise and you can usually feel the escaping gas. Some enterprising people on this site have diagnosed the escaping gas using a stethoscope - worth a try. The posts on this forum that describe the symptoms of the problem also identify a significant loss in power and fuel economy. The problem is associated with a warped exhaust manifold and broken studs that hold the manifold to the head. The repair is expensive because of the new manifold(s) but more so due to the stud locations and access that may require additional components to be removed.

Good luck.

 

[blakusta]

I have a rattle in my 07, the inside of the muffler has come apart and rattles. Its annoying. New muffler would fix that i think

 

[thebrakeman]

Thanks, Town. I can get the rattle, even after the truck is warmed up, so it sounds like my exhaust manifolds are OK.
Pretty sure the noise is forward, so I don't expect the muffler.
I'll check all of the hangers.