Hi Guys,

Over winter car developed an engine metal knocking noise and it keeps increasing with time. I am changing oil religiously every 5000km and use suggested semi-synthetic 5w-20.

VIDEO

When I just start car - it is quiet for 5-10 seconds and then the noise kicks in. It does not go away once car is warmed up.

Have been told by one of the technicians that it is a piston slap - supposedly a common problem with non-sufficient oiling in cylinder 2 for Third Gen TLs.

Is that the case? Is there a cure? Is it safe to drive like this?

Every feedback is welcome!

Thank you for your comments!

 

motor is done dude. Could be piston slap or a rod bearing failure. Take it easy if you drive it and put thick oil in it. You need a rebuild or new short block at least. Good luck how many km/miles is on the car? Id use 10-40 oil until your ready to rebuild. It will eventually totally blow up..how long will it take? who knows.

 

The motor has just 140,000km on it.

I do not feel any vibration , increase in consumption of gas or oil, or drop in power

 

If you rev the engine up past 1200 rpms does sound go away?

Sounds similar to my tick:
https://acurazine.com/forums/3g-tl-problems-fixes-114/valve-tick-injector-click-860485/

http://s131.photobucket.com/user/jis...75417.mp4.html

 

Guessing it's a 6MT??

 

How long have you been driving the car with that noise?

Sounds like it could be a spun rod bearing that's got a foot half out the door. Since it's continuously getting louder you're probably almost done with the process. You'll know when it loses power.

I doubt it's a piston slap issue but stranger things have happened. Either way, plan on opening 'er up!

 

I would not say the sound goes away above 1200rpm - it changes though.

VIDEO


I have also tried to unplug spark plug wires one by one and revved the engine.

The sound did not disappear/change for any cylinder in particular that does not really match with spun rod bearing or piston slap symptoms...

 

So much for that theory....not a 6MT.

 

Yeah that's going to be a spun rod bearing.

That is not a normal sound from the valvetrain by any stretch of the imagination.

 

It's hurt for sure. Most likely a hurt piston/pin. Rod knock usually has a lower, more solid sound, not a clack. Rod knock will always get worse as the engine warms up. Rod knock will usually cause a partial loss of oil pressure but in some odd cases oil pressure can actually increase. If it spins a rod bearing there will be a terrible squeaking sound with the knock.

Piston slap will always get better as the engine warms up.

There's always the loose sparkplug thing but practically no chance of that being the problem. Just had to mention that for the hell of it.

I'm guessing once this starts it doesn't get much better or worse with changing temperature.

It's hard to tell but it sounds like it gets worse under load and better when you let off the gas and it coasts back to idle.


Can you describe in more detail how this happens, if it gets worse as the engine warms up? No low oil pressure light at hot idle? It *should* get louder under load, even moreso than with rpm.

Last, a rod knock will usually hold together for a while if you drive it easy. A damaged piston/pin can let go at any time even in your garage revving it so be careful and have a fire extinguisher ready.

It would really help if you could do another video revving it and letting it fall back to idle quickly. I wouldn't go past 2,500rpm but rev it then let off the gas completely.

Another helpful video would be to put it in gear and let it sit there for a few seconds, then lightly powerbrake it and see if the noise changes under load.

Has this engine ever been hydrolocked???

 

Dang, stop driving it before it causes more damage. Good luck!

 

Not sure that I agree with you on this. A hardware problem in the rotating assembly will usually stay there regardless of if the spark plug above a certain piston is firing.

I'm not sure what your problem is, but I wouldn't start ruling things out based on that.

 

Hi tsurik,

Can you post an update on this issue? I'm very concerned about this also! Thanks.

 

Sorry, just had to clear something up. Killing spark is the usual way to find which cylinder has a rod knock or a damaged piston. You only hear the rod knock on the power stroke. Getting rid of the power stroke by killing the spark will usually silence the knock completely.

True piston slap is the piston rocking in the cylinder usually only when cold before the piston has time to warm up and expand. It's more of an annoyance. A damaged piston will make noise kind of like piston slap but a lot worse. Rod knock usually has a squeak or screech to it in addition to the knock.

 

Update

Went to number of mechanics and dealership - all came to the conclusion that it is piston slap.

Overtime noise become louder and I can clearly hear it with Windows open.

I am looking for an engine replacement before winter comes ads I have been told that it is going to be much louder with cold.

I have also changed to synthetic oil - it did not help at all and may be even make it a bit worse since it is thinner oil.

 

I would run a 40wt, at least a 10w-40, not a 0w-40 until temps get below freezing. A synthetic 40wt is ok until nearly 0F but you would want to take it easy and warm the oil up before high rpm operation.

If this were traditional piston slap it would be worse when the engine is first started, is it worse when cold? The piston can be hurt but it doesn't sound like traditional piston slap which is just a loose fit in the bore. I wouldn't treat this as traditional piston slap where it's just an annoyance. I would treat it as a damaged piston (assuming the mechanics were correct that it's a piston which is doubtful) and drive it nice because it can let go at any time. Keep the rpms down at all costs.

I can't remember but you've confirmed it's not a loose plug, right? I can't remember what it sounded like and I can't watch the video at work.

What's throwing me is the noise not changing as you unplugged coil packs. That pretty much rules out rod knock. A piston can still make noise with the cylinder shut down but it should change in intensity.

 

hey i have the same problem with my 6 speed tl did you ever figure out the problem or you just replaced your whole motor?

 

My engine sounds like this at idle but my knock goes away when I rev it. I've been driving it like that for a year now with no issue. I don't even baby it. Some mechanics will tell you these hobda engines can run like that for a really long time. In the case of OP, his knock sounds serious so a used short block or a rebuild might have to be done sooner than later.

 

It doesn't sound too horrible in your case though, but who knows.

 

That's because you haven't listened to it closely lol. It's driving me crazy. Every time I drive the car is a constant battle between "fuck it i'll have the thing rebuilt" and "fuck that shit I'm driving it until it breaks". Not a good feeling man

 

looks like i need to save up for a used block before my motor sh*ts the bed lol

 

Sounds just like the rod knock I had on my Grand Prix before I blew the motor.

Sucks....

 

I've been driving it like that for over a year now. Not even babying it. I'll almost be relieved the day it breaks down, the knock takes away a lot out of the driving experience (at a drive through, at stop lights with no music on, anytime there's no sound to cover it up)