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hollow rattle...

S

Speed_racer

NAXJA Forum User
Location
Ft Myers, Florida
Ive got a hollow rattle that is intermittent in my jeep.. Comes during first few seconds on crank, then good til warmed up, then goes at it again.

Thought it was my flexplate.. replaced it.. no dice...

She holds perfect oil pressure, runs strong, has blowby... Is this rods? lifters? What can I do to specifically diagnose/fix the problem?
 
Speed_racer said:
Ive got a hollow rattle that is intermittent in my jeep.. Comes during first few seconds on crank, then good til warmed up, then goes at it again.
Click to expand...

Where is it comming from? Under the Jeep I would say rattling exaust. or just a bad cat. I had the same problem though it was under the Jeep so I changed the cat. sounds great i plan on installing a glass pack or a flowmaster delta 50.

Speed_racer said:
She holds perfect oil pressure, runs strong, has blowby... Is this rods? lifters? What can I do to specifically diagnose/fix the problem?
Click to expand...

Now I am not an expert on this one if it is under the HOOD i could be the timing belt.
 
x2 on the cat I have a rattle for only about 5 minutes max then it is gone till it is cold again
 
another vote for the bad cat... had a rattle on start up every time. replace the cat when i installed headers all the way back and the rattle was gone...

once the cat was actually out of the system, you could hear the conb inside loose.
 
Front of the engine or at the rear?
 
Speed_racer said:
This is intermittent, and in direct relation to the RPM's of the motor.
....
Click to expand...

more RPM's means more flow out of your exhaust... right?
not saying that it's definatley the CAT, but don't count it out
 
just went thru this with mine, was the torque converter bolts, they had come loose.
could be it.
 
COULDNT FIND EDIT BUTTON!!!!!


How can I find The exact source of a rattle?

-Could be lifters...
-Could be rod bearings...

Its intermittent, in relation to the temp of the oil, it seems. Although Straight 50w does not fix the problem.

Its a hollow rattle, in direct relation to the RPM's of the motor.

after much research, thought it was the flex plate, replaced it, no dice.

It has this hollow rattle during first 2 seconds of running, then after i run for 1-2 minutes it's back, and stays. Was low on oil one day (due to blowby catch can design), and when the oil pressure dropped, it got MUCH worse.

Still have perfect oil pressure/pickup/power.

So what can I do, thats the most simple, to diagnose whether or not I can just swap heads, or if I need a whole new motor/rebuild?
 
beakie said:
just went thru this with mine, was the torque converter bolts, they had come loose.
could be it.
Click to expand...

Definitely couldve been a possibility.. although we did think it was my flexplate, possibly cracked, so we replaced it, which it wasnt cracked, also this means the torque converter got removed/reattached so its all tight.

Weirdest thing is that the sound went away for a whole day after we replaced the flexplate.. and then it came back, lol. Definitely was not the source of the problem tho, the old one checks out real clean.
 
Speed_racer said:
COULDNT FIND EDIT BUTTON!!!!!


How can I find The exact source of a rattle?

-Could be lifters...
-Could be rod bearings...

Its intermittent, in relation to the temp of the oil, it seems. Although Straight 50w does not fix the problem.

Its a hollow rattle, in direct relation to the RPM's of the motor.

after much research, thought it was the flex plate, replaced it, no dice.

It has this hollow rattle during first 2 seconds of running, then after i run for 1-2 minutes it's back, and stays. Was low on oil one day (due to blowby catch can design), and when the oil pressure dropped, it got MUCH worse.

Still have perfect oil pressure/pickup/power.

So what can I do, thats the most simple, to diagnose whether or not I can just swap heads, or if I need a whole new motor/rebuild?
Click to expand...
one way is to pull a spark plug wire off a plug,hold it a half inch off a ground.if the sound is at the same speed as the arching it is at crankshaft speed and your problem is in the bottom.if it is faster it is cam speed and it's a lifter.to fix a lifter do an oil change,add 4 qts of 10-40 and a qt of tranny fluid(dex III preffered)run for 10-15 minutes or until nice and warm and drain.refill and your good!
 
Last edited:
use a long piece of rubber hose. Hold one end to your ear and probe with the other end. Using this method you should be able to pinpoint you rattle, almost exactly.

Don't get the your hose caught in the fan!
 
oh and if you do the lifter thing,while runnin' it for the 10-15 mins,don't go above 2000 rpm but slowly go up and down on throttle so the tranny fluid can work it's way to the lifters.
 
Dont forget the transfer case linkage - mine is rattling intermittently, and it sounds terrible. Thought stupidly that something serious was going on, until I got under there and wiggled the linkage...
 
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