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Reliability of 4.7 vs HEMI
Administrator
Joined: Jul 2007
Posts: 24,686
Likes: 21
From: South Georgia/East Florida
RE: Reliability of 4.7 vs HEMI
10 MPG, that's crazy! I'm getting 13.8 - 14.2 in combination driving from my lifted Hemi that now weighs in at close to 7000 lbs.!!!
My 4.7 is getting me 21.9 right now (overhead read out only) I know only 67 milesis not a true test, but I was pleasently surprised, so far, especially since it's the 265 HP H.O. version and it's in a Jeep Grand Cherokee 4x4. Really pushes that mid size SUV quite nicely too, only mod that I can tell it has is a fairly new (judging by shine and condition) Maganflow exhaust ( well, at least the muffler isa Magnaflow).
My 4.7 is getting me 21.9 right now (overhead read out only) I know only 67 milesis not a true test, but I was pleasently surprised, so far, especially since it's the 265 HP H.O. version and it's in a Jeep Grand Cherokee 4x4. Really pushes that mid size SUV quite nicely too, only mod that I can tell it has is a fairly new (judging by shine and condition) Maganflow exhaust ( well, at least the muffler isa Magnaflow).
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: Reliability of 4.7 vs HEMI
Only widely discussed design problem on the 4.7 V8 has been the 'brown goo' at the oil filler tube.
4.7 has been re-designed for this year with twin sparkplugs, more torque and 5% better fuel economy...are you thinking of this new model or buying used?
5.7 has a longer history of problems and corrections. Even before released for production the cam bearing began failing and introduction of the 5.7 was delayed 3 years. First 3 years of production had 'Hemi Tick' noises due to sloppy fit of exhaust valve guides to valve stems...and Chrysler refused to issue a recall due to high $ cost. 5.7 has a very small distance from the top of the first piston ring groove to the crown of the piston (called 'ring land') and to protect this there is a special chemical coating (anodzing) that has given some problems and there have been postings of 5.7 engines failing both in and out of warranty connected to this piston weak spot. Also keep in mind the transmission & torque converter versions for the 5.7...both have had failures due to the higher torque loads at shifting (search 'Torque Management) and Chrysler's choice of part materials (plastic TC parts)
But a 5.7 with MDS will have better daily driving MPG than the older version of the 4.7 in normal driving...this is true both of official EPA tests and numerous owner reports. If the new 4.7 twin sparkplug version only has 5% better fuel economy the 5.7 will still be equal or better.
4.7 has been re-designed for this year with twin sparkplugs, more torque and 5% better fuel economy...are you thinking of this new model or buying used?
5.7 has a longer history of problems and corrections. Even before released for production the cam bearing began failing and introduction of the 5.7 was delayed 3 years. First 3 years of production had 'Hemi Tick' noises due to sloppy fit of exhaust valve guides to valve stems...and Chrysler refused to issue a recall due to high $ cost. 5.7 has a very small distance from the top of the first piston ring groove to the crown of the piston (called 'ring land') and to protect this there is a special chemical coating (anodzing) that has given some problems and there have been postings of 5.7 engines failing both in and out of warranty connected to this piston weak spot. Also keep in mind the transmission & torque converter versions for the 5.7...both have had failures due to the higher torque loads at shifting (search 'Torque Management) and Chrysler's choice of part materials (plastic TC parts)
But a 5.7 with MDS will have better daily driving MPG than the older version of the 4.7 in normal driving...this is true both of official EPA tests and numerous owner reports. If the new 4.7 twin sparkplug version only has 5% better fuel economy the 5.7 will still be equal or better.
Record Breaker
Joined: Jul 2007
Posts: 1,023
Likes: 0
From:
RE: Reliability of 4.7 vs HEMI
I have a friend who is a Dodge mechanic. He told me the 3.7L is far and away the most reliable followed by the 4.7L then Hemi. Thought I think the "Hemi Tick" gave that engine a bad wrap.
Professional
Joined: Nov 2006
Posts: 193
Likes: 0
From: Maricopa, Arizona
RE: Reliability of 4.7 vs HEMI
ORIGINAL: HankL
Only widely discussed design problem on the 4.7 V8 has been the 'brown goo' at the oil filler tube.
4.7 has been re-designed for this year with twin sparkplugs, more torque and 5% better fuel economy...are you thinking of this new model or buying used?
5.7 has a longer history of problems and corrections. Even before released for production the cam bearing began failing and introduction of the 5.7 was delayed 3 years. First 3 years of production had 'Hemi Tick' noises due to sloppy fit of exhaust valve guides to valve stems...and Chrysler refused to issue a recall due to high $ cost. 5.7 has a very small distance from the top of the first piston ring groove to the crown of the piston (called 'ring land') and to protect this there is a special chemical coating (anodzing) that has given some problems and there have been postings of 5.7 engines failing both in and out of warranty connected to this piston weak spot. Also keep in mind the transmission & torque converter versions for the 5.7...both have had failures due to the higher torque loads at shifting (search 'Torque Management) and Chrysler's choice of part materials (plastic TC parts)
But a 5.7 with MDS will have better daily driving MPG than the older version of the 4.7 in normal driving...this is true both of official EPA tests and numerous owner reports. If the new 4.7 twin sparkplug version only has 5% better fuel economy the 5.7 will still be equal or better.
Only widely discussed design problem on the 4.7 V8 has been the 'brown goo' at the oil filler tube.
4.7 has been re-designed for this year with twin sparkplugs, more torque and 5% better fuel economy...are you thinking of this new model or buying used?
5.7 has a longer history of problems and corrections. Even before released for production the cam bearing began failing and introduction of the 5.7 was delayed 3 years. First 3 years of production had 'Hemi Tick' noises due to sloppy fit of exhaust valve guides to valve stems...and Chrysler refused to issue a recall due to high $ cost. 5.7 has a very small distance from the top of the first piston ring groove to the crown of the piston (called 'ring land') and to protect this there is a special chemical coating (anodzing) that has given some problems and there have been postings of 5.7 engines failing both in and out of warranty connected to this piston weak spot. Also keep in mind the transmission & torque converter versions for the 5.7...both have had failures due to the higher torque loads at shifting (search 'Torque Management) and Chrysler's choice of part materials (plastic TC parts)
But a 5.7 with MDS will have better daily driving MPG than the older version of the 4.7 in normal driving...this is true both of official EPA tests and numerous owner reports. If the new 4.7 twin sparkplug version only has 5% better fuel economy the 5.7 will still be equal or better.
