Engine ' clack ' at around 2-3 rpm

[blackcurrant]

I've been noticing this sound on my 94 MTX (98k miles), a rat a tat or clack like card in bicicle spokes...not loud at all only between 2-3 rpm is it audible (it might still be there but the engine noise is overcoming it, i think) ,under load mostly..sounds 'flat' -like a diesel. it fades above 3krpm. It was becoming more apparent after i changed the oil with 5w30 mobil 1. I read the pertinent search matches and drained the expensive synthetic and replaced it with castrol 10w30 'for higher mileage engines'. It does seem to be going away.

What's causing the sound?

 

[Chrisssssssss]

I would stop driving your car right now if you want to keep that engine. I had the same problem leading up to rod bearing failure. I would check your rod bearings immediately. If you catch it in time, then you can replace just the bearings, and be on your way. If the crank gets messed, you are in a whole pile of mess. This is where I would start to look. Does it make more of a clatter between you first turning the key and the aengine settling to an idle? This is another sign of failing rod bearings.

 

[Spin]

that is a sign of rod failure!!! same thing happened to my 91 with 235k on it, go get it checked ASAP! it'll be a sad day if it dies on u frown

 

[Spin]

just wanted to add that chris said it all

 

[Denny]

Then prepare to welcome yourself to Kia ownership!

 

[Mike Kopstain]

Denny:
Then prepare to welcome yourself to Kia ownership!

Yeaaaak! Get those bearings taken care of!!!! eek!

 

[blackcurrant]

OK...OK i stopped driving it!

Now, i just started it in the garage to listen for the clack. It isn't there at startup or idle. and revving it abit doesn't produce the sound either...the waterpump or idler pulley is rattling, however

Ummm, it only occured under load at low RPM... couldn't it have been a valve tick from the synthetic?

 

[DavidT]

Does it make more of a clatter between you first turning the key and the aengine settling to an idle? This is another sign of failing rod bearings.

sounds ... -like a diesel.

Hey, this is me! Except it is VERY occasional. Only notice it aT IDLE, and when coming to a stop. I cant hear it when revving. Lucas oil stabalizer has helped the start up noise. Currently I dont hear anything. Am I in for a very unpleasant surprise?
Also, if they are on their way out, what are the things you want to avoid doing when driving?

 

[SHO SPD]

Your SHO isnt real high mileage, but that sounds like a bearing, I had the same thing happen to me.. If you can, buy an oil pressure gauge AND NOW! or spend the $20 and get ne bearings, very cheap, and will save you from buying a new motor!

 

[DavidT]

oil pressure guage for what? to make sure I maintain the proper amount of oil?
If the oil level stays in the required level, are the rod bearings safe?

 

[Denny]

Nope, my oil level was always good, I always check at a fill up, so my oil level didn't do anything to save my bearings

 

[BeatDaSHO]

No, an oil PRESSURE gauge is what they are talking about. It checks the oil pressure to make sure it is at a safe level. When rod bearings thin out, the oil pressure drops and therefore you end up hearing a rod knock. Correct oil pressure at an idle would be between 10-12psi. It doesn't matter how much you fill up your oil. If that is at the proper level and you have lower than about 7 psi, looks like your bearings need to be swapped out.

Greg

 

[Mike Kopstain]

dkautumna:
I cant hear it when revving. Lucas oil stabalizer has helped the start up noise. Currently I dont hear anything. Am I in for a very unpleasant surprise?

Everyone that sticks Lucas oil stabilizer or any other oil thickener in a car to cover up a noise is due for an unpleaseant surprise. If you guys want to keep your cars you are going to have to learn to fix the problem, not the symptom.

I'm not trying to come off like an a$$hole or anything, but I've seen way to many people put additives in their oil to quiet a noise, only to have their engine experience catastrophic failure weeks or months down the line. Then they act all surprised that their car broke down.

Also, if they are on their way out, what are the things you want to avoid doing when driving?

</strong>

The things to avoid would be anything that requires the engine to turn over.

<small>[ November 14, 2002, 05:28 PM: Message edited by: Mikeys_Taurus ]</small>

 

[blackcurrant]

If it isn't noisy at idle is it still the rod bearings. It's not even 100k miles and i have oil change records for the car. I wonder what else it would be?

Where do we fit up the gage? Thanks!

Mike

 

[sdpatt]

Does the noise get louder when you take off the oil fill cap? That would indicate the front bank valve gaps need attention. Listen to the rear bank with a long, thin rod such as a screwdriver placed against the rear valve cover. If your noise sounds much louder and clearer, you may just have worn shims. Noises are very hard to diagnose over the internet.

 

[blackcurrant]

Thanks Scott...I'll try that, but, I really only hear it under high load (almost lugging) between 2-3k RPM....here's an update...i had just changed the oil to himile GTX and i still had the the old filter...i cut it open and could NOT find any copper! I would guess that's good news, huh? Since i put the himile GTX in it's been quieter.

Thanks for all your help, guys!

 

[shojuan]

Quit using that crap Mobil 1 synthetic! Use some good stuff like Redline. I've never heard any of these Mobil 1 horror story noises with redline 10W/30.

If you can't afford redline then just use GTX and change it often.

Cheers beer

Rick

 

[Off Road SHO]

" I really only hear it under high load"

When under "load", your rod bearing are subjected to the most punishment. I know it's a PITA to remove the Y pipe and starter and oil pan, but it would be cheap insurrance to put some new rod bearings in and at the same time some new mains. Our engines like to rev and there's nothing better than a small gap between crank and bearing to help it do that.

An accurate oil pressure guage is also nice to have.

Tom

 

[sdpatt]

Thomas, when you say the mains, do you only replace the lower bearing surface? Have you been able to replace the upper surface without removing the crankshaft? That is a much bigger effort.

 

[RTStabler51]

Scott,

On my Ex-93 we did rod & mains. Very easy ;-) and it was my first time. Though it did help having a lift.

sdpatt:
Thomas, when you say the mains, do you only replace the lower bearing surface? Have you been able to replace the upper surface without removing the crankshaft? That is a much bigger effort.