Engine knocking???

[mickfoely]

So i've been using this 93 Chrysler lebaron v6 for awhile now. It has 184,000 miles, this spring its started making ticking sound, it would come and go and fade away as i drove faster. The car burns some oil, and when i put in more oil the ticking sound would just stop for awhile. Some days it just does't make that sound. Its aways worst when i first start the car, or sitting at a stop light and take off.

I wasn't going to take the car in to get looked at, or take apart the engine, just like i wasn't going to replace the rings to stop the oil. It simply wasn't worth it.

Well today i was driving home and it now started knocking on the highway, its a dull knocking sound, that is not constant, just like the ticking. Sometimes the knocking will stop suddenly, then start back up. It seems to fluctuate. If i stick my hand on top of the engine cover i think i can feel the bumping vibrations.

Like i said i'm not really interested in having this fixed. Unless its something cheap and easy i can do myself. The most i ever did was change sparkplugs, change a starter, and drop a tank to put in a new fuel pump.

Is there some way i can get it to last a little while longer even with the knocking?

Oh is there a final warning sign right before the enigne blows?

[mickfoely]

Anyone know of a v6 or general engine site forum or board that might be of help?

[mickfoely]

I'm not losing any oil pressure either.

[534BC]

It could be a number of things, I'd guess a wristpin loose. Or maybe something in the valve/lifter/pushrod area. A good engine shop can tell right off what it is.

[mickfoely]

Is there an easy way i can rule out a rod knocking or bearing?

[mickfoely]

Started the car up and let it idle a bit, its quite loud kinda sounds like electric sparks a bit now. As soon as i gave it some gas the sound went away, then came back but not as loud.

Maybe its detenation.

[Moppie]

Originally Posted by mickfoely

Oh is there a final warning sign right before the enigne blows?

Sadly it sounds like a bearing has gone.
If your lucky the knocking will get really, really loud for a short period before it fails. Depending on the bearing, and how badly it fails the engine may sieze, it may put a rod through the block, it may just run really rough for a few km's before expiring.

Sadly theres no way to find out untill it happens.
Best suggestion is buy another car, or replace the enigne.

[mickfoely]

Too late to replace the bearing? Or is it not worth it?

[MagicRat]

Originally Posted by mickfoely

Too late to replace the bearing? Or is it not worth it?

Usually a by the time a bearing starts to knock, the bearing journal (thats the metal smooth metal surface upon which the bearing rotates) is already damaged.

can be scratched, scored, pitted, or be out-of-round.

If this has happened, the engine needs to be removed so the crankshaft can be removed and machined, usually all rod and/or main bearing journals are machined and polished, and new bearings installed.
Often the rods and bearing caps are resized, too.

IMO if you do all this work, you may as well rebuild the entire engine, or find a new/used one to install.

If you are VERY LUCKY, you may just be able to drop the pan, locate the loose bearing, remove it, polish the journal with fine emery paper (if its not badly damaged) and replace those 2 bearing shells. However, this is a gamble, the knock may return soon.

[534BC]

Trying to piece this together,

Ticking that comes and goes, high mileage, burn some oil, ticking since spring, adding oil stops ticking, worse wwhen cold start or when taking off from light,

Now is knocking, starts and stops, not constant, no oil pressure loss. sounds like sparks, detonation still coming and going.


It really could be detonation, or a pin/piston or a shaft endplay. A bearing probably will not last a long time and usually is hard to make conme and go like you describe. If the ticking from before and the knocking now is the same noise I'd still look towards a pin/piston that finally broke or something in the valvetrain/lifter/pushrod? I don't know this specific engine, does it have push rods?

Detonation sounds like 1 or more marbles rattling in a can (lots of cars detonate when pushed) A piston/pin will sound almost like a double knock/tick (almost like a two stroke) Valvetrain,lifter/pushrods is just a single ticking. A bearing will vary with load and can sometimes be made to go away if the load is right, but will may not be as sporadic as you describe unless it is the endplay on the crank.

A couple things to try might be to drop into forward and or reverse when revving slightly to see just when it's the worst. Pull plug out to look at them, pull valve cover off and run it to check for top-end knocks. As I said before a good engine shop can probably "guess" what is knocking on the specific engine or can just simply hear it becayuse they do so many of them.

In any case you are real close to needing a rebuild anyways because of oil presssure and mileage.

I hope it is something in top like extra clearance or detonation.

[mickfoely]

Okay so when i rev the engine to 2000 rpms, there is a pause, then it sounds like tap dancing, or a machine gun. Very eradic though.

If anyone want to hear it let me know.

[UncleBob]

diagnosing noises on a forum is kinda like explaining to a blind person what the color blue looks like.

It could definitely be a lot of things. It could definitely be the last leg for the engine. Its most likely something that is not cheap.

Just drive it. If it blows, it blows. If you really want to find out more about it, take it to a shop and have an experienced mechanic take a listen to it. He'd probably be able to narrow it down at least, and it would probably cost you very little

[534BC]

No one mentioned exhaust leak, it can also be a ticking. Worst when cold, and possibly non-existant when warmed up. Probably not your problem, but easy to check by plugging tail pipe and start engine cold.

[mickfoely]

The car is not worth paying for a diagnostic test. I wouldn't get it fixed anyways, i'm quite sure its something not easy and cheap.

I'm just wondering how long it will last as is. Say if i keep it at 35 and off the highway.

[UncleBob]

my shop offers a free inspection with an oil change. Oil change cost $20.

Many shops will offer something simular.

Is this worth a cheap oil change and a free inspection? Since you're concerned enough to ask a forum about it, I would assume it is....