Just as the title might indicate, I need to know if it's possible to have inconsistent rod knock, and also not super loud.

My car does not "tap" when first started, but once warmed up, It does a bit..... but only sometimes. The noise comes from the head, sounds like normal dsm tapping of lifters or cams to me. Maybe a collapsed lifter..... dunno.

The noise that is concerning me is when I'm slowing down, not on the gas at all, from about 25mph down to 10mph, I'm getting what I am HOPING I'm mistaking for rod knock....... as I can hear it with my window down, and it sounds as if it's coming from my front left tire. I don't THINK I'm hearing the engine tap. It really sounds like rod knock to me, but a VERY mild case, and not all the time. Is this possible?? It's been happening for about a month or more now. I have not lost any power, and it doesn't make the knock while accelerating, OR idling......... ONLY when slowing down while not pushing the gas pedal at all.

Any and all FAST information would be so appreciated, as I'm suppose to purchase my sig'd FP BLACK tomorrow, and I need to know if I should be investing in a built engine instead if this is indeed rod knocking.

 

take a look at the oil for shavings of bearings. Sounds like lifters to me i would think if it was rod knock it would get worse and worse

 

My thoughts exactly, but I'm still a little un-nerved about it. As I say, the knocking isn't there while accelerating, I haven't lost ANY power, and it's intermittent......... never consistent. That's why I wanted to know if it's possible to have rod knock, sometimes?? Not to mention I'm fixing to spend BOOKOO money tomorrow on power parts, and if I need to rebuild, I want to do THAT instead of buying power that I won't need if the engine goes Kabloue.

 

Did you check your CV joints? That may be a possibility.

 

do not go out and spend a lot of money on performance parts until you find out exactly what this issue is.. jus my opinion cause it can be something ver costly although it does sound like it could be a lifter a rod knock would definitely be a problem towards drivability performance and not to mention consistent

 

when slowing down? that could be a number of things coming from there. could be something dumb for all you know suspension related. drain the oil and check for metal shavings. if there are none i wouldnt worry about a rod knock because if it happened enough and it was a rod knock there would sure to be shavings in the oil pan or filter

 

If it was rod knock it would be more consistent. Rod knock comes from either excessive side or oil clearance on the rod bearing. It would do it pretty much every rotation.
I have had a few vehicles that had some weird suspension noises but that was because the bushings and balljoints were shot.
I would look over everything such as drivetrain and suspension. Jack up the car and just by jiggling things you may find the problem. Look over dust boots, ball joints, bushings, CV/ujoints, shocks.

 

My guess would be your clutch, unless it is happening while you are slowing down with clutch pedal to the floor. My Exedy twin makes noise when I slow down while still engaged.

Rod knock is very pronounced and you can definately hear it even with a warm engine.

 

multi plate clutches make a grinding noise though not a knocking sound

 

Its hard to distinguish noises with wind noise, engine noise, exhaust noise etc. I've heard knocking noise from a friends car while at idle that we thought was rod knock. I put my stethoscope on the tranny and it was the clutch. It was plain as day.

I'm just giving the OP another possible thing to consider looking at.

 

yeah it could be a ton of things

 

btw does this happen when slowing down decel or while using the brakes?

 

The stock lifters are notorious for this . That is why they sell aftermarket hydraulic lifters to remedy this. It could possibly throw a rocker arm due to excessive play, but like stated rod knock does not go away unless the rod is knocking for a long time and the bottom breaks as well as the top of the rod leaving just a piston in the cylinder at bdc. but you would then only be running on 3 cyl lol. I don't know if you have had your cams out, if so and you did not bleed the lifters this will happen as well.I say 1 bleed your lifters. If that does not remedy your problem 2 purchase new aftermarket revised lifters. Good luck either way. Take car of this before performance mods like you had already mentioned might be a good idea.

 

You know, I thought it could be the clutch too. As it isn't consistent with the rpms when slowing down, but rather, it's consistent with the revolutions of the drive train. So if it is the clutch, does that mean it needs replacing? I have a triple disc. Does the clicking mean replacement time, or is this just a normal thing?

 

I had an engine with rod knock (not a 4g63) and it only knocked at coast down. However, the noise this engine was making rapidly got louder.