View Full Version : Horrible rattling noise
4x4Dreamer
09-19-2006, 05:49
My 6.2 has developed a horrible rattling sound from the front of the engine. I did the old 2x4 to the ear trick and couldn't track it down. I think it's coming from the alternator, but I'm not positive. I hear that the bearings make a horrendous sound when they go out. If that is the case:
How do I make sure?
Can I just replace the bearings?
If I have to replace the alternator, is there a preferred one to use?
How hard is the swap?
Could the rattle be anything else?
First off
Pull all the belts off and run the engine for a short to see if the noise is still there.
The alternator can have issues as well as the water pump or any other belt driven accessory.
With the belts off give the water pump a spin by hand as well as the Alternator and such.
Let us know what you find
Robyn
DmaxMaverick
09-19-2006, 07:43
Do as Robyn says, then inspect the balancer VERY closely, ASAP. If you have a balancer problem, the rattle could be, or could lead to a broken crank.
4x4Dreamer
09-19-2006, 08:41
I should say, the noise goes away when you take it anything above idle. It runs nice and smooth. but as soon as RPM's drop back to idle, it comes back.
My 84 6.2 had this horrible noise up front at idle.
The belts can magnify the noise too and pick up a harmonic.
The water pump can be almost to the point of sending the propeller through the radiator and all you get is a horrible noise at idle.
As Maverick says do check the ballancer.
I'll bet you its the water pump. Check to see if the pulley will wiggle and or if the thing is noisy when spun by hand.
While checking the HB, don't overlook the accessory drive pulley - it's totally rubber-isolated, also, and subject to the same deterioration, with same disastrous results
If I read this right this rig is older than the rubber isolated pulleys.
The early rigs with all the v belts had issues with vibration up front.
I have converted my 84 engine to serp drive ala 93 6.5
doncannon
09-19-2006, 20:20
Hello All,
Eric: With the engine off (I know but sometimes we dont think) grab the fan blade and wiggle it front to back and see if it moves. If not try loosening the belts a little and recheck. If it does move then it is probably the water pump. SHORT STORY: I stopped to see a friend of mine, he was inside getting ready so i decide to check the oil and it was fine. I grabbed the fan blade for no apparent reason (yes engine was off) i guess just dumb luck. The fan blade must have moved 1/8 inch (oops) So like Robyn said it could have sent the fan through the new radiator I bought. It is good to have a little luck now and then.
Just my 2 cents worth hope it helps,
Don
Ahhh, yes, yes, I see now - '82-'85 - stamped steel pulley.
Never mind............
doncannon
09-19-2006, 20:21
Hello All,
Eric: I agree with all of the above and would like to add. With the engine off (I know but sometimes we dont think) grab the fan blade and wiggle it front to back and see if it moves. If not try loosening the belts a little and recheck. If it does move then it is probably the water pump. SHORT STORY: I stopped to see a friend of mine, he was inside getting ready so i decide to check the oil and it was fine. I grabbed the fan blade for no apparent reason (yes engine was off) i guess just dumb luck. The fan blade must have moved 1/8 inch (oops) So like Robyn said it could have sent the fan through the new radiator I bought. It is good to have a little luck now and then.
Just my 2 cents worth hope it helps,
Don
4x4Dreamer
09-27-2006, 17:22
Okay, I finally got over the sickness that had infected, and tried to kill me. Man was that horrible.
So tonight i went out and pulled all the belts. The alternator pulley looks a little warped, but it seems tight. All the other with the exception of the power steering pump pulley are tight, and it just clicks a little. the fan has no front-to-back play at all. I fired it up with the belts off and I still hear the noise. It's coming from the top front of the engine. I had my wife come listen too so I knew I wasn't crazy.
Is there any way the timing chain could be doing it? It sounds like a grinding type noise.
Any input is greatly appreciated.
Warren96
09-27-2006, 23:20
How about taking off the oil filler cap, and listen to see if it gets louder?
see at idle if depressing the brake, turning the wheel, or flipping the a/c on makes the rattle louder...that would be the power steering pump. Battling with that one myself at this moment.
trnpkroadwarrior
05-24-2007, 20:22
What if it does get louder when you take off the oil filler cap? What would that indicate?
read my above post at your own peril. I'm still experiencing the same rattle after I replaced the steering pump. :(
If the noise is that loud I would rip off the front cover.
Now you can remove the water pump and the top metal cover and not have to rip the whole timing cover off.
This will allow you to see the top gear and such.
The bolts that drive the IP could be coming loose. If one falls into the chain and gears its game over. :eek:
I would check this before I run it any more.
The bolts that hold the top gear to the IP should be locktited with Blue when they are put into the pump.
There is a lignup dowel the indexes the pump to the gear and if the bolts are coming loose it can make terrible noises as well as run crappy.
The timing chain could also be very loose causing things to rattle.
On some engines there is a metal shield behind the top gear that could have loosened?????????
Have a look see. This is not a big job, but it you fine the need you can move a little farther and remove the complete cover with little more work.
Get the fan off as well as the shroud out of the way and you will have plenty of room to work in comfort. :)
Good luck and let us know
Robyn
For you guys with serp belt - and you know who you are! - the tensioner also fails, not just the idler pulley - remove the belt, swing the tensioner thru it's complete arc - if it scrunches at any point, replace it - that's the noise you hear - and the pulley, while you're at it
More Power
07-30-2007, 14:13
How many here have watched while a Stanadyne DS4 was being bench tested? It's way louder than you might think. I suspect a DB2 would also produce similar noise (more like a clicking noise). A bad DB2 could make even more noise. Just a thought....
Jim
I like that busy ticking sound - loud rattle could also be loose timing gear - drive or driven - if it gets louder when the oil filler cap is removed, time to pull the waterpump for a looksee
When my engine broke its crank it would still start up and run but it made a horrible noise from the front of the engine. it broke at the first rod journal. before you do anymore damage(that is if something is sereously wrong inside) I would pull the lower part of the bell housing off, grab the flexplate or flywheel, and give it a turn. watch to see if the harmonic balancer and the flywheel are moving together. thats how I found out that my crank was broke.
kconnair
07-30-2007, 18:35
The noise 4x4 dreamer is almost certainly the pulley assembly bolted to the balancer or the balancer itself. I have had both fail at different times, and they both sounded the same once the rubber was gone. Luckily I didn't hurt the crank or block with either misadventure.
Just my $0.02
Kevin.
Leadslinger11b
07-31-2007, 20:19
I dont mean to hijack here but just how loud should the 6.2 be normally, Ive had several people this year comment on how loud my engine is, I tell em it's a Diesel, some say oh and leave it at that, others say its too loud even for a Diesel. Now any CUCV ive driven in the Army had a 6.2, and I think my truck sounds like any of them, or am I just crazy? Sorry but this thread is puttin some worries in my dome.
DmaxMaverick
07-31-2007, 20:50
I dont mean to hijack here but just how loud should the 6.2 be normally, Ive had several people this year comment on how loud my engine is, I tell em it's a Diesel, some say oh and leave it at that, others say its too loud even for a Diesel. Now any CUCV ive driven in the Army had a 6.2, and I think my truck sounds like any of them, or am I just crazy? Sorry but this thread is puttin some worries in my dome.
A few things can cause an engine to be more loud than the "norm".
Does it have an intake baffle? That would be a canister (not the air filter) inline with the intake pipe. N/A intake can be very loud w/o it (not turbo to baffle the intake pulse).
Straight piped or glass packed? No brainer, there.
Timing. More advanced timing will increase engine noise. Sometimes a lot, and it will be exaggerated by a missing intake baffle and/or straight/glass pipes.
Individuality. Some are just louder, with no explanation.
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