What problems to look for with '02 Grand Cherokee with 4.7L

[wirenut]

So I think I'm about to purchase my first Jeep. I found an '02 Grand Cherokee with 115,000 miles. I think I can get it for around $4,000. I was looking for a 6cyl. but this one has the high output 4.7L V8. What's this engine like for reliability? Obviously it's got plenty of power but how do they hold up. What's the real world gas mileage like? The transfer case is full time 4wd which I'm guessing isn't as good on gas mileage as part time but probably not much different. How well does this 4wd system do for long term reliability?
Any real problem areas I should be aware of with this model?
I'll use this Jeep mainly for highway driving including snow. Also light duty off roading on dirt, gravel, and rock roads with my family.

 

[skeeter06]

The biggest thing is the 4wd system has issues before the engine. My Dad bought one with 200k+ on it. His had transfer case issues due to improper care, but all of them that I have seen eventually have 4wd issues

 

[Mitch502]

Rust. Always look for rust.

Just look for the typical signs its been taken care of. I like to think that if I look in the harder to reach places, like door jambs, under the hood, etc and see some form of care given to it, then it's probably been cared for pretty well.


I've never heard anything much about the 4.7 (no news = good news), and parts are plentiful for them.

 

[BCobe]

Gas mileage will vary depending on what you do. I had a 6 inch lift with 35s and was getting like 10ish MPG mixed driving. Look out for electrical issues also and make sure that the connections at the battery terminal are good because those have tend to get all messed up somehow.

Check the A/C also! The blend doors tend to go but they are fairly easy to replace

 

[huntermax1014]

All those are issues to a degree especially the blending doors... That one is expensive to fix if u take it to the shop. the most common is broken manifold bolts..

( . Y . )

 

[Gldwnguy]

Long time lurker here. Guess it's time for a post. I would strongly recommend having a compression test done. Had a valve seat issue with mine and blew the piston out the side of the block, no warning or anything. It's one of the few known problems. Otherwise it was an awsome rig.

 

[wirenut]

I asked a mechanic friend today about the 4.7 engine. He said he would much prefer the 4.0. He said the 4.7 had some problems with plugged oil screens or passages.
I haven't been able to find much online bad about the engine other than running it hot is very bad. Valve seats falling out from overheating the head, etc.
The Jeep in question had just been traded in so they hadn't run it thru their shop yet. I'm waiting to hear what the verdict and actual price are.

 

[AZMP]

I've seen a ton of over heating issues with 4.7Ls so check the oil for contamination if it hasn't been changed recently. Look for typical issues with the dana 30 axle. An 02 grand shouldn't have the akebono brakes so check for warped rotors as well.

 

[BCobe]

All those are issues to a degree especially the blending doors... That one is expensive to fix if u take it to the shop. the most common is broken manifold bolts..

( . Y . )

Key word is "IF" you take it to the shop. I do not remember how much the part was but it really wasn't that much. I was then able to accomplish the fix with a multi-tool and drill. You lose dual climate control but it wasn't a huge deal breaker to me.

I had the regular 4.7 and honestly the only real problems I had was the oil sensor going out, a bad coil and a injector going out. This was all around 140K miles and all easy fixes.

I honestly loved my WJ and really thinking about getting another.