2004 JGC Limited-4.7 HO engine
 

Hey guys, first post here at jc.com! Woo! :smokin:

I'm looking at purchasing a 2004 JGC Limited with the 4.7 HO, and it has QuadraDrive (only 4HI-N-4LO). It has 158,000km's on it and seems like a sweet machine.

But I've never heard of the 4.7 HO, only the 235hp 4.7 L. Is the HO a good engine? Any known problems or upcoming repairs due to high mileage to be aware of? What sort of mileage can I expect from this vehicle? Are parts more expensive for HO vs. the standard 4.7? Should I keep looking for a JGC with a 4.0L in-line 6 instead?

I'm surprised to see that the 4.0L in-line 6 doesn't get better mileage than the 4.7, it's only a marginal difference. Thanks for all the help! Much appreciated!

Re: 2004 JGC Limited-4.7 HO engine
 

The 4.0 is an updated version of an engine that has been around in one form or another since the late 50's/ early 60's....So, although very reliable if serviced regularly, its not the most powerful or efficient engine.

The 4.7 and 4.7HO are very similar with only 30hp & 30ft/lbs between them. The main difference from a service perspective is that the HO models require platinum tipped spark plugs.

Expected life...both 4.7L engines were designed to be 150 000Mile / 95th percentile engines....(so, 95% should still be running well at 150 000 miles or +/- 240 000 kms.)

The I6 is easier to work on at home due to simplicity and sheer space in the engine bay. The V8s both get comparable mileage to the I6, but are more difficult for the at-home repairs.

One point to note is that the transmission mounted behind the V8s is a very reliable and strong model, whereas the I6s got a much weaker/older design. The tranny behind the V8s is still used in the 2012 Jeep/Dodge V8 models (although with some upgrades.)