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Unread 11-14-2014, 01:18 PM   #1
ZJjustin
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08 WK 4.7L Rod Knock

I'm looking at buying an 08 WK with 90k miles on it for 12,000. It's in really great shape beside what sounds to me like engine rod knock. Anyone on here have to do that repair? The dealership said they'd give me a deal of paying 400 for them to do it, and they'd eat the rest of the cost. But I know the bearing set is pretty dang cheap. If it's not too much work getting that pan off, I could probably just do it myself. I've rebuilt 2 engines successfully thus far. Or am I crazy for even thinking about buying something for that price with such a problem? They paid 11000 for it on trade, so I know I can't wiggle them any on price...and it's a beautifully black Jeep.

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Unread 11-14-2014, 01:28 PM   #2
wranglin95
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If it's a rod why do you want to toss in new bearings?
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Unread 11-14-2014, 01:30 PM   #3
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Quote:
Originally Posted by ZJjustin View Post
I'm looking at buying an 08 WK with 90k miles on it for 12,000. It's in really great shape beside what sounds to me like engine rod knock. Anyone on here have to do that repair? The dealership said they'd give me a deal of paying 400 for them to do it, and they'd eat the rest of the cost. But I know the bearing set is pretty dang cheap. If it's not too much work getting that pan off, I could probably just do it myself. I've rebuilt 2 engines successfully thus far. Or am I crazy for even thinking about buying something for that price with such a problem? They paid 11000 for it on trade, so I know I can't wiggle them any on price...and it's a beautifully black Jeep.
So, is the dealership admitting it does have rod knock that needs fixed?

If that's the case and they only want $400 bucks that seems cheap as I imagine it's a job heavy on the labor side.

If all else is good offer them $11500 for the Jeep, $400 for the repairs. They make $500 bucks and you pay $100 less for a rig that needs repair outta the gates.
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Unread 11-15-2014, 01:22 AM   #4
joe989
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Take it to another mechanic and have him assess it, the dealer may know more about this engine and that the rod knock could be the tip of the iceberg. get a full compression check, etc.. if they do it, make sure you have some kinda warranty on it.
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Unread 11-15-2014, 08:14 AM   #5
Tekn0logy
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Sounds like a "tip of the iceberg" thing. I just got my WK at a dealer auction and found damn near 100 things wrong after I got it home. Two of those things were the wrong fluids in the transfer case and power steering pump. The rod knock is the most obvious defect and they would put their reputation at risk if they let something so visible get sold to an unsuspecting customer. I would hazard a guess that the vehicle's maintenance records are not available or your mechanic can determine that the vehicle was poorly maintained. What the dealer wont tell you is that if you have one spun or spent bearing then whatever cased it (low oil pressure?) probably damaged all the other bearings, so yeah eating parts & labor on one bearing set is a bargain for them.
BTW; two people I knew that thought they could swap a spent bearing on car eventually wound up junking them. (not jeeps; one the crank was toast, the other eventually threw a rod.)
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Unread 11-15-2014, 10:39 AM   #6
modernblueWK
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Seems like they should fix it before you buy it. Or fix it before they sell it to anybody else. Seems shady.
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Unread 11-15-2014, 07:18 PM   #7
ZJjustin
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They are a fairly reputable dealership for the area, I believe they are the largest in the state, but I guess that says something on its own. They've admitted to me that anything over so many miles ( I can't remember) they just so a basic state required safety inspection and sell it as is. In this case, they gave 11k on trade in, NADA trade in value in good condition was $11,200. That is to say, I can believe they didn't do a good inspection or they wouldn't have given so much on the trade. I've replaced rod bearings on both the engines I rebuilt, and replaced the rod bearing on an Oldsmobile intrique that had developed rod knock, for a friend that owned said car. In all cases, the rod bearing journals on the crankshaft were in perfect condition and the engines lived long happy lives with a new set of bearings in them. However, i will agree that my biggest concern is if there is an oil pressure issue with this vehicle, with the need for new rod bearings so early in its life, the life of a motor that seems to be pretty well respected. Do these things have an oil pressure monitor in the message center of the instrument cluster? I know there's not a gauge, unfortunately. Also, its me saying it has rod knock, not a mechanic or their service department. Its a pretty distinct noise when you hear it. As of now, they will be fixing it for free Monday morning. Thus i will have the opportunity to hear and see what the mechanics did to it before i sign anything.
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Unread 11-16-2014, 06:01 PM   #8
twistedlizard72
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Being that the 4.7 is a SOHC layout, what would it be that would cause a "rod knock" type sound?
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Unread 11-16-2014, 07:34 PM   #9
JeepN4KC
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Unfortunately, there is nothing that gives oil pressure reading.
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My Other Build Thread XJ
'01 XJ with some stuff
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'07 WK with some other stuff
~RED WK CLUB #7~
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'06WK our first Jeep with stock stuff - totalled and gone
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Unread 11-17-2014, 02:42 PM   #10
ZJjustin
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twistedlizard,around my parts rod knock is defined as a connecting rod bearing have excessive play between the I.D. of the bearing surface, and the O.D. of the crankshaft journal. When there is too much slop there (The bearing has become damaged),as the piston moves up and down, the rod bearing is effectively bouncing around on its' crank journal. This creates a very distinctive noise.

JeepN4KC, thanks, that's good to know I guess.

Anyway, the service department determined the rod bearings have been replaced before, so there must be a serious underlying problem in that motor. They're going to put a bran new engine in it, with Chrysler footing part of the bill. $1500 increased cost to me, for a brand new Chrysler warrantied engine, in a Jeep that only has 90k miles on it. pretty good deal in my opinion.
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Unread 11-18-2014, 05:26 PM   #11
ZJjustin
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Well, it wasn't rod knock. Apparently every main bearing was worn past acceptable limit, with metal flake in the oil pan. They're not replacing the entire engine however, just the short block, but they're warrantying it for 2 years, unlimited miles, at aforementioned cost to me. I'll take it.
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