So what do you guys know about the durability and reliability of the 3.7 V-6 and the 4.7 V-8 that Chrysler uses in the Dode trucks, Jeeps etc... How do they compare to the older 3.9 V-6 and the 5.2 V-8?
Chrysler 3.7/4.7 engines
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The 4.7 seems to be a reliable motor with decent power for a smaller V8. Can't comment on the 3.7
There were some teething issues on the early 3.7.
Head gaskets, etc.
Head gaskets, etc.
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I have the 4.7 in a 2002 Dodge Ram 1500. 240,000 and still running storng. Not very good MPG and decent power. Early models (like mine) had a less than effective PCV system, but if you cahnge the oil at normal interval and clean/maintiain the PCV you should be good. One thing that Ive seen alot of on these engines is neglected cooling systems, which results in blown head gaskets, and then it just gets worse from there. I had the 5.2 liter in a previous Dodge Ram 1500 and it was a good reliable engine, but worse MPG and I had to use premium fuel or I would get pinging during acceleration. I used to tow a five thousand pound trailer with both of these truck and I can say that the 4.7 did MUCH better job of towing.
i put 60,000 on a 3.7, with some mild off-roading and occasional towing. It had a mild lift and slightly larger tires, so the engine worked a little bit more than stock. It was smooth and consistent, never consumed any coolant or oil, and that was even with the 20 weight, MS6395-approved synthetic oil.
It could make a little bit of chatter with some oils, especially when it was hot, like 100F interstate driving, but I never had any trouble with it.
It could make a little bit of chatter with some oils, especially when it was hot, like 100F interstate driving, but I never had any trouble with it.
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Yea early 4.7's had some sludge issues if you pushed the change to long. The 3.7's were not as smooth and I have heard of head gasket issues, not sure how common that was though.
I have a 2007 Dakota with the 4.7. Decent power, reliable so far, but low gas mileage.
My front crank seal is leaking but that is not uncommon and not to hard to change.
The biggest reason I got the 4.7 V8 over the 3.7 V6 was the V8 came with the newer transmission, 5+1. The 3.7 came with the older, and more problematic, 4 speed. Seems with most trucks the transmission will have problems long before an engine will if maintained.
I have a 2007 Dakota with the 4.7. Decent power, reliable so far, but low gas mileage.
My front crank seal is leaking but that is not uncommon and not to hard to change.
The biggest reason I got the 4.7 V8 over the 3.7 V6 was the V8 came with the newer transmission, 5+1. The 3.7 came with the older, and more problematic, 4 speed. Seems with most trucks the transmission will have problems long before an engine will if maintained.
Don't let them get hot.
^^^^
Lots of guys on Jeep forum have the 4.7, they will last a long time IF they are well maintained and they are never allowed to over heat. Cooling system maintenance as a preventative measure is important. Both the 4.7 and 3.7 will drop a valve seat which can be a disaster, that is usually associated with overheating but not always.
The 3.7 we have in our family has been rock solid and trouble free, it's a noisy sucker though.
Lots of guys on Jeep forum have the 4.7, they will last a long time IF they are well maintained and they are never allowed to over heat. Cooling system maintenance as a preventative measure is important. Both the 4.7 and 3.7 will drop a valve seat which can be a disaster, that is usually associated with overheating but not always.
The 3.7 we have in our family has been rock solid and trouble free, it's a noisy sucker though.
I've got an 08 4.7, and its been great. The 4.7 got a significant re-design in 2007 that bumped the rated horsepower from something like 240 up to 310 in the Ram, ~300 in the JGC. Its got to wind up pretty high to make that power, but it'll do it all day in, day out. The early version is an 8-spark-plug hemi head with single overhead cam and 2 valves/cylinder (16 valve), the later revision is a 16-spark-plug slant-squish head, still SOHC, 16 valve. The overall architecture is a lot like a Ford Modular, but the cam drive on the 4.7 has an intermediate shaft and 3 chains instead of 2 long chains.
The block is cast iron, and the bottom end is, frankly, built like a battleship. Its a deep block, and then on top of that there's an integrated bedplate/cradle that carries all the main bearing caps as an assembly, and the oil pan bolts below that.
The earlier version of the 4.7 had a strange habit of sometimes spitting a cam follower out under the valve cover causing a dead miss. If you poke around on youtube you can find videos of how to pop it back in place with a screwdriver, and at least one tutorial on how to shim the hydraulic lash adjuster to make it impossible to fall out again (be careful not to cause it to bind, though, as that could lead to a burned valve). This also tells me that an oil filter with a good anti-drainback valve is crucial, since its the hydraulic lash adjusters going slack on startup that can cause the follower to jump out of place.
The block is cast iron, and the bottom end is, frankly, built like a battleship. Its a deep block, and then on top of that there's an integrated bedplate/cradle that carries all the main bearing caps as an assembly, and the oil pan bolts below that.
The earlier version of the 4.7 had a strange habit of sometimes spitting a cam follower out under the valve cover causing a dead miss. If you poke around on youtube you can find videos of how to pop it back in place with a screwdriver, and at least one tutorial on how to shim the hydraulic lash adjuster to make it impossible to fall out again (be careful not to cause it to bind, though, as that could lead to a burned valve). This also tells me that an oil filter with a good anti-drainback valve is crucial, since its the hydraulic lash adjusters going slack on startup that can cause the follower to jump out of place.
Originally Posted By: eljefino
Seeing a lot of Jeep libertys with blown 3.7s. IDK about their owners though.
this can be read in several ways.
Seeing a lot of Jeep libertys with blown 3.7s. IDK about their owners though.
this can be read in several ways.
Originally Posted By: Jarlaxle
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
Mom has the 3.7 in her 2005 Jeep Grand Cherokee. She has over 160,000 miles, and the only engine part that ever needed replacement was the oil pressure sensor. That was about 5,000 miles ago.
It is a great engine, but I maintain it carefully and only use the HOAT coolant that it calls for. I have been told that if anything goes wrong in the cooling system, such engine will drop out valve seats, and cost thousands of dollars in repairs.
It is a great engine, but I maintain it carefully and only use the HOAT coolant that it calls for. I have been told that if anything goes wrong in the cooling system, such engine will drop out valve seats, and cost thousands of dollars in repairs.
I had a 2003 4WD Durango with the 4.7, and it was a very reliable car. It only got 13 mpg, though. Only problem ever was a power window regulator.
Originally Posted By: earlyre
Originally Posted By: Jarlaxle
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
Premium? In a 4.7?? Shouldn't be required, although maybe it was for the "HO" version of the first-generation. It should be noted that the first-gen "HO" engine put out about 50 horsepower less than the standard 2nd-gen.
But you're right about the general trend in power and torque, and that's why the 4.7 is no longer built by Chrysler. The Pentastar V6 has 305 horsepower compared to the 4.7's 310. And if you need torque instead of high-revving power, well the 5.7 Hemi with MDS has the same or better fuel economy than the 4.7 did, while having a LOT more torque. The 4.7 got squeezed both from above and below until it was redundant in the engine lineup. Great engine, but with no application anymore. The 3.7 was totally out-classed by the Pentastar, as were the 3.3, 3.5L and 3.8L v6 engines. Chrysler replaced 5 engines with 1 in the Pentastar- some of the 4.7 market share, plus all of the 3.5 OHC in the Charger/Challenger, the 3.7 in Jeeps, and the 3.8 in Wranglers and minivans, and the 3.3 in minivans.
Originally Posted By: Jarlaxle
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
Premium? In a 4.7?? Shouldn't be required, although maybe it was for the "HO" version of the first-generation. It should be noted that the first-gen "HO" engine put out about 50 horsepower less than the standard 2nd-gen.
But you're right about the general trend in power and torque, and that's why the 4.7 is no longer built by Chrysler. The Pentastar V6 has 305 horsepower compared to the 4.7's 310. And if you need torque instead of high-revving power, well the 5.7 Hemi with MDS has the same or better fuel economy than the 4.7 did, while having a LOT more torque. The 4.7 got squeezed both from above and below until it was redundant in the engine lineup. Great engine, but with no application anymore. The 3.7 was totally out-classed by the Pentastar, as were the 3.3, 3.5L and 3.8L v6 engines. Chrysler replaced 5 engines with 1 in the Pentastar- some of the 4.7 market share, plus all of the 3.5 OHC in the Charger/Challenger, the 3.7 in Jeeps, and the 3.8 in Wranglers and minivans, and the 3.3 in minivans.
Originally Posted By: 440Magnum
Originally Posted By: earlyre
Originally Posted By: Jarlaxle
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
Premium? In a 4.7?? Shouldn't be required, although maybe it was for the "HO" version of the first-generation. It should be noted that the first-gen "HO" engine put out about 50 horsepower less than the standard 2nd-gen.
is it required? no, it will run fine on regular, but Premium is Recommended. "it runs better and makes more power with the premium" (his words), and the Ford Racing tune on his Mustang calls for premium, so he just runs it in both.
Originally Posted By: earlyre
Originally Posted By: Jarlaxle
In a 4WD Dakota, avoid a 3.7-it's just not enough for the weight. (In a crewcab 4x4, it is truly painful.)
My Brother has a Crewcab 07 Dak 4x4, w/ the HO 4.7. plenty of power to get it moving, but fairly thirsty (for Premium)
that said, the 3.5 v6 in my Sable,( and MANY ford products, including f150s) has slightly higher peak HP, and only about 10 fewer torques in it's NA configuration.
in it's D.I. Twin Turbo configuration (EcoBoost), Fuhgeddaboudit.
not anywhere near an apples to apples comparison i know, but...
Premium? In a 4.7?? Shouldn't be required, although maybe it was for the "HO" version of the first-generation. It should be noted that the first-gen "HO" engine put out about 50 horsepower less than the standard 2nd-gen.
is it required? no, it will run fine on regular, but Premium is Recommended. "it runs better and makes more power with the premium" (his words), and the Ford Racing tune on his Mustang calls for premium, so he just runs it in both.
I own a 2004 grand cherokee with the 4.7ho. The high output version has a forged crank, more aggressive camshafts, connecting rods have floating wrist pins (vs pressed fit on the regular 4.7, the heads were also revised and the intake manifold has shorter runners. There are also two knock sensors in the block valley that can take advantage of 93 octane, but it can be ran on 87. Overall the changed were good for 35-40 hp and 30-35 ftlbs of torque over the standard 4.7. Mine has 141000 miles and runs like a top. dosnt use any oil between changes and the only thing I've had to do to it since I bought it with 75000 miles is regular maintenance and a water pump. in 2008 Chrysler squeezed another 25-30 hp out of the 4.7 but torque output stayed the same as the 4.7ho (330 ftlbs). but that year grand cherokee needed it because of the extra weight. I will say that my jeep with the 4.7ho feels stronger and is quicker than a 2005-2010 grand cherokee with a hemi. Surprised many people at a stoplight. the bottom line is keep the maintenance up on them, don't run em hot, and they make a good torquey powerplant.
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