Bad noise on 98 4.0 Wrangler

hscrugby

Well-Known Member
Joined
Mar 22, 2005
Location
Raleigh, NC
OK, so Monday night my Jeep starts making a super loud god awful, holy cow I just threw a rod and she's out the side of the engine type noise.
It was loud enough my roommate two cars in front with his windows up heard it.
I'm slowly uploading a video with the noise, but it's hard to tell just how loud it was.
I've pulled the intake/exhaust manifolds off, no cracks, pulled the valve cover off, looked at everything, no ideas.
The weird thing, after it started making that noise, it drove fine. (until I started taking the engine apart obviously.)
No power loss, no engine codes, nothing. Just a HORRIBLE noise.
Anyone got any guesses on what I can look for in the mean time?
here is the video:
 
Does it make the sound when it sitting at a stop idling?
does it change with engine speed?
Is it possible one of the accessories has failed? (water pump, AC compressor, alternator, PS pump, Fan) ...take the belt off the front of the engine and see of the noise gets louder ;)

I was lookin for you at the tap room a while ago
Steve
 
Wrist Pin? For whatever reason they have had more than normal WP failures in the Later 4.0's. A CoWorker had one go bad on a 2000 GC recently.

Use a long screwdriver and use it as a stethoscope to pinpoint where the noise it coming from. The louder the noise, the closer you are to the problem. This should tell you if it's internal or not quickly. Be careful around the fan/belt area!!

That does not sound like an exhaust leak.
 
rbo1577186 said:
Wrist Pin? For whatever reason they have had more than normal WP failures in the Later 4.0's. A CoWorker had one go bad on a 2000 GC recently.
Use a long screwdriver and use it as a stethoscope to pinpoint where the noise it coming from. The louder the noise, the closer you are to the problem. This should tell you if it's internal or not quickly. Be careful around the fan/belt area!!
That does not sound like an exhaust leak.
Click to expand...

X2. That is not an exhaust leak, that is internal.
 
is the oil pressure gauge still read normal? sounds like a rod knock to me tho... you can drain your engine oil and see if you have small particles of metal in it.
 
Caver Dave said:
Chris, any chance this is an automatic?
Click to expand...
Not an automatic.
Anyway without a complete tear down to check for wrist pin failure?
Anyone in Raleigh want to come over and help me tear it down etc etc? I can either provide food/beer, or if you actually know what you're doing and can really help me get this fixed will give some cash too.
I can't drive it anywhere, as I have no manifolds on there, etc etc.
:)
I drained the oil, no metal at all in the oil, but it was kind of gross.
I also took the valve cover off, cause well, I figured I'd just start taking things apart. :lol:


Thanks for any help.


Oh yea, Oil pressure was reading normal when I was driving it last.
 
Using a stethoscope you can determine internal/external. You won't know what it is internal until you break it down and start investigating.

Hold off on taking everything down..... you never know.

A neighbor of mine had a Durango that sounded like it had a terrible "knock".. as if it were on it's last leg. Using a "stethoscope" I found the culprit to be the power steering pump. A local shop didn't bother to check it out and told him he needed a new engine.

If it's loudest at the heads, block, valve cover or the part of the exhaust manifold near the heads it's most likely internal. If it's one particular valve/piston/wrist pin/ you will be able to determine which cylinder the problem is in by moving from cylinder to cylinder.
 
rbo1577186 said:
Using a stethoscope you can determine internal/external. You won't know what it is internal until you break it down and start investigating.
Hold off on taking everything down..... you never know.
A neighbor of mine had a Durango that sounded like it had a terrible "knock".. as if it were on it's last leg. Using a "stethoscope" I found the culprit to be the power steering pump. A local shop didn't bother to check it out and told him he needed a new engine.
If it's loudest at the heads, block, valve cover or the part of the exhaust manifold near the heads it's most likely internal. If it's one particular valve/piston/wrist pin/ you will be able to determine which cylinder the problem is in by moving from cylinder to cylinder.
Click to expand...
I used a stethoscope on it when it was running,
Seemed to be coming either from the #1 (closest to radiator?) cylinder or from the #5 area. But was DEFINITELY not from an accessory.
 
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