Chrysler PowerTech 4.7L engine issue

[Tobra]

You need to find a different dealership.

[beepbeep]

Originally Posted by drcoastline

Thanks for all the posts.

Just to fill you in a little bit more. When my factory warranty was expiring I purchased an aftermarket warranty for $1,200.00. It covers 60 months or 100,000 miles which ever comes first for all engine, drive train, internally lubricated components and associated electrical items. That is 100,000 miles over the mileage at the time of purchase.

I spoke to the mechanic today who I trust and has done right by me so far on other vehicles. The shop manager that I spoke to yesterday I have had minimal interaction with in the past, but he just doesn't seem reputable to me. I think he smelled easy money. When I dropped it off I did not authorize any repairs, only diagnosis as the repair may be covered by the warranty.

So today when I met with the mechanic he stated he confirmed two broken studs on the back of the exhaust manifold which I knew. He further stated he used a mechanics stethoscope on the engine to see if he could locate the source of the tapping I explained. He stated when he used the stethoscope on the bottom of the engine

"he could hear an internal tapping noise"

I concur with you guys every rod knock I have ever heard sounded like a power stroke diesel, you didn't need a stethoscope to hear it.

The shop owner was in ear shot as the mechanic and I had our conversation and I questioned the shop managers explanation and statement the vehicle needed an engine. At this point the shop owner chimed in stating the manager most likely recommended the engine swap as it is often cheaper to buy a re-man than rebuild the original as the rest of the engine is still original and could potentially fail down the road.

I explained that is all well and good however, a swap would devalue the vehicle as 1. the numbers would no longer match. I wasn't all that concerned about that. But more importantly I would no longer be able to certify the mileage should I choose to sell or trade it in at some point. He didn't have much to stay after that. Again, my opinion is the shop manager smelled easy money counted on my not knowing or questioning his statement and lastly I think the mechanic and owner tried to cover for him.

So right now I haven't made any decisions but am leaning toward nkowi's suggestion and having the studs repaired. I will bring it home and see how it sounds, performs and see if anything changes, get a second or third opinion and I will also do the engine oil check as MrMerlin suggested.

I am open to any other suggestions you all may have.

Thanks again for all your in put thus far.

....he needed stethoscope to hear "internal tapping noise" in reciprocating internal combustion engine? I bet he did!

It's probably just a exhaust gasket leak due to broken manifold studs. Couple of hours (worst case - stud extractor) and it will be fine.

[EarlyPorsche]

My broken studs have sounded EXACTLY like every bottom end knock i've had or heard. Its nuts to think but the stud from the dealer was like $10 and fixed everything.

There was a 1 or 2 year only twin plug 4.7 actually. Not real common but it was out there. They made a second iteration of the 4.7 then with the economy and car industry cut it out and kept it simple with the 5.7 being the only V8.

[drcoastline]

You could be right about the twin plug 4.7L. I don't know really. I know the engine was in several other Chrysler products as well. I just assumed since the Hemi was a twin plug the 4.7 wouldn't be.

The sound I hear definitely isn't as loud as rod knock sound but loud enough to get my attention when the engine is cold. It sounds to me like it is coming from the top vs. the bottom and it quiets down as it warms up.

My first step is to get the studs repaired. Then get a second possibly even a third opinion on the tapping sound. I will move forward from there.

Thank you all again for the input. As usual this forum is awesome with great people. I posted on the Jeep Commander forum a day before posting here. I have only received two replies on that forum. I just assumed people would be as eager to jump in over there as they are here. A person can get spoiled hanging around here.

[drcoastline]

So I took the Commander to a local Jeep dealer for diagnosis. There were a few days between the time I took the Commander from the old service station and my appointment date at the dealership last Thursday. I drove it during that time to listen to the engine run to see if anything changed. I hear the same tapping sound as before, no better no worse. The tapping slowly quiets down as the manifold heats up. I desperately tried to hear sounds from the bottom of the engine to validate the old stations claim. Every once in a while I thought maybe there is a knock. But I really could not tell.

During one of my rides I had another incident where the vehicle suddenly turned left on it's own. Shortly there after it felt like the 4wd system went into 4 low. A whine started in the rear that progressively got louder.

When I dropped it off asked the service manager to have both issues looked into.

The diagnosis on the engine is no bottom end issues, it just needs the manifold bolts replaced. They plugged her in and ran a diagnosis, a sensor in the 4wd system was going bad causing the right front to get power. That was replaced and fixed the turning issue. The rear end sound is the differential locking up, they're not exactly sure why but stated the rear including the axles need to be replaced. They recommend a rebuilt unit from Jasper, roughly $4,500.00 installed. I did a little research and it appears the differential locking damaging the axels is a relatively common issue. It's not wear and tear. I had the Service Manager turn it into the warranty company, so far so good they have approved the work.