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4.7 knock!!!

1K views 15 replies 11 participants last post by  GTPDrew 
#1 ·


Listen to the noise and let me know what you think, this is my buddies jeep, 4.7 with 160k miles. He said it ran low on oil for a day, and the noise has worsened to this. Any help would be great. I personally think it sounds like a bearing and/or a broken rocker. But I don't know, engines aren't my thing

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#2 ·
How low is "ran low on oil for a day"? Throwing any codes? Either way, you'll need to pull the valve cover and/or oil pan to diagnose further. Most likely, it isn't good.
 
#10 ·
It's a camshaft noise....it's knocking at half engine speed so can't really be anything else. Either a follower destroyed or a cam lobe....or both. When oil level drops the top of the engine usually suffers first...cams etc.
 
#7 ·
Sounds like a dangerous game to play...
 
#8 ·
rloew275 said:
So if anyone was to guess what this could be what would you guess? I know he's gotta pull off the valve covers first of all, and then yank the oil pan to really tell, but what exactly do you think it is? Sent from my iPhone using JeepForum
Knock like that bottom end is shot. Tick is upper valve train. Tell your buddy congrats. His neglect over $25 in oil cost him $2500 repair.
 
#11 ·
mr312712 said:
I don't see why people can't take 1 minute to check oil I check mine whenever I'm under the hood and I'm under there almost every day and then wonder why they have problems.
True story.... Young lady bought a new Miata..... 36000 miles later she calls the dealership because it would not crank. Car towed in.... Zero oil left in sump . She had never changed nor looked at the oil. For that dealer that was the first Miata engine failure in the six years they had been selling the car. The young lady claimed no one had ever explained required maintenance to here. Hmmmmm
 
#12 ·
Ah673000 said:
True story.... Young lady bought a new Miata..... 36000 miles later she calls the dealership because it would not crank. Car towed in.... Zero oil left in sump . She had never changed nor looked at the oil. For that dealer that was the first Miata engine failure in the six years they had been selling the car. The young lady claimed no one had ever explained required maintenance to here. Hmmmmm
I had something similar. A friend in the marine corps bought a new mustang GT and the salesman told him to watch the oil level on it and he should be fine. At 35k the engine locked up. He said he always checked the oil level and he only had to add a little bit of oil since he's had it. Never changed the oil just added to it. Quite a bit of money later and a new engine, now he just takes his car in to get services.
 
#14 ·
4.7's are dying right and left on this forum, mine included. Just check out all the recent posts, it looks like an epidemic (anyway that's the way it looks to me because I caught the dropped valve seat that destroyed my engine disease). Probably lots of 4.7's reaching 150,000 to 200,000 miles and self destructing. Valve seats dropping, head gaskets blowing, rod bearing problems, piston skirts breaking, valve train problems, etc. Rebuilding or remanufacturing 4.7's is becoming a big business. You guys that are professional mechanics and shop owners are going to make a fortune of off these 4.7's. We that have a 4.7 and are mechanically challenged better take a good course in engine repair and figure out how to do a lot of things ourselves or we will go broke.

btw, my 4.7 never overheated, was always well maintained, always used Mobil One, but still managed to drop a valve seat and destroy my engine. I wished I got a WJ with the old 4.0 but now I will have a brand new (remanufactured) 4.7 with all the design problems fixed, at least that's what PowerTrain Products tells me.
 
#15 ·
common, engine holds 6 qts, this guy indicates his buddy only had 2 qts left.

The 4.7 is no different than any other engine, run it low on oil, neglect oil changes, neglect cooling system, over heat it etc and you can have a wallet flush performed replacing engines.

Look on CL and see how many high mileage WJs are out there.
 
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