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Discussion Starter #1
I got a 1989 bronco with the 4.9L, it runs really good, dosnt burn any oil has plenty of power, but its noisey, lower end bearings sound like they are going to fall apart, only at idle, and when i first start it up, oil pres seems fine, with the in dash gauge have not put a real gauge on yet to see what it really is? is this sort of common, i only have 120k, and it looks as if the truck has been babied, doesnt even have a towing package on it. i been hearing people talking about having 150K plus and its jsut breaking in? anyinfo would be great.. BTW sounds like its mostly from cyl 5..
 

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How are you figuring it to be low end?

Are you just going by proximity of the noise when standing next to the truck? You say at start up and idle. Noise that goes away with increased rpm doesn't sound like low end bearings to me. They normally get louder and match rpm's. Top end noise can radiate and sound like its coming from elsewhere. Need to check oil pressure mechanically, also, get a mechanic's stethescope to help pinpoint where it's coming from. If it is low end, the motor's basically a ticking time bomb. If you're gonna drive it, do it as little as possible and baby it til you figure the problem.
 

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yeah...hook a mech gauge up to it and see what it's doing...one of my friends has almost 500,000mi on his 4.9 in a f-150 and other than oil changes and replaceing a lifter/valvecover gasket and oilpan gasket the motor has never been apart. his makes no lower end noise
 

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aka: kemicalburns
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what brand oil filter do you have on there. if its a fram filter replace that with a motorcraft or wix or purolator. the fram are known to cause pressure issues. i would also look at your exhaust manifold for cracks. you probably just have some bad lifters
 

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I also ave a 6 in my 89 bronco. it has recently developed a knocking sound at an idle. It had me concerned I even thought it was a rod rattling. but after carefull inspection i found out that it was the idler pulley. I had the same problem on my mustang. I replaced it and the noise went away. I would check it out also like dan73 said inspect your exhaust mani's
 

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Discussion Starter #7
i used a stephiscope to pinpoint the noise, iam pretty sure its in the lowerend around cyl 5 area. or towards the rear i mean., i jsut changed the oil, i just bought this bronco and the noise was not that bad, very little. i drained the old oil and it looked fairly think, even tho it was hard to tell. so i put 5w30 in it, and now it wont make the noise on cold start up, and makes it worse at warm idle. before it was real bad when cold and minor at warm idle. i am goign to put some 15w40 in it now, see what happens. maybe ill pull the pan and inspect the bearings and see if i can get away with replacing a rod bearing or two, seems kinda lame to have to buy a long block at 120k, but never kno. ill try to get the most out of this engine since i have no driveabilty issues so far.. yeah i kno about the fram and most aftermarket filters, new 5.4ls are haveing a huge problem with any aftermarket filters, ford is reccomending only motorcraft filters for those engines, we are finding pieces of the aftermarket filters in oil passages. i only use motorcraft, but right now i got bosch on there, filter before was a napa, thanks for all the info...
 

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Discussion Starter #8
anyone know of good places to get a long block or maybe a whole rebuild from?? maybe in cali would be good... whats a typical price...
 

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Discussion Starter #9
i work with so many over head cam engines at work i dont even t hink of lifters being so low on the engine like on my 4.9, gotta listen around ther emore maybe ill get lucky and its a lifter or pushrod problem for sure not a valve rocker adj, tho, there is no noise that high up.... thanks for the info, got me thinking a little...
 
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