Odd Noise, Need Your Suggestions - 986 Forum - The Community for Porsche Boxster & Cayman Owners

jrgill · 05-16-2019, 03:21 PM

I took the car out for a ride this evening and felt or heard no engine issues while driving. But, when I returned home and pulled it into the garage I heard a noise that’s not normal. I’ve attached a YouTube video link with the sound included and would appreciate your suggestions on what could be the cause.

https://youtu.be/O_xgIHQJXkw

Thanks
Joe

maytag · 05-16-2019, 03:47 PM

Hmmm...... I'm sorry..... that sounds engine internal, and to me it sounds bottom-end. Based solely on the sound in the video, I'd be scared right now.

How handy are ya?

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jrgill · 05-16-2019, 05:29 PM

Oh, I was hoping I wouldn’t get that type response. I’m fine with rebuilding a front end suspension but I’ve never removed and rebuilt an engine...if that’s what it needs.

pomerlo · 05-16-2019, 05:48 PM

Could be a water pump, an alternator bearing.... etc...
Do you have that noise when the engine is cold ?

Remove the belt and start the engine for a few seconds... still noisy ?

Get a stethoscope and pinpoint the exact location...

Dont conclude too fast....

Good luck

jrgill · 05-16-2019, 06:00 PM

Pomerlo - thanks for the positive thoughts and your suggestions. I’ll take your advice and give it a good once over this weekend.

maytag · 05-16-2019, 06:26 PM

Pomelo is right on target.... I just didn't know how handy you are. ;-)

If it doesn't do it when cold, that suggests (but doesn't specifically identify) internal.

Next step, (warm it if you have to so the noise is evident) pull off the serp belt. You can run the car for a minute without the belt on to see if you can still hear it. (Your water pump won't be turning, so not too long). You're HOPING at this point that thr noise is gone, because that means it's one of your peripherals. You can narrow that down by spinning them by hand and listening / feeling how they turn.

But if the noise is still there (warm or cold) then you need to get dirty. Get your stethoscope (a long peice of aluminum rod works really well). Hold one end to your ear, place the other end at various places on the engine and find where the noise is most evident. That should help you get it narrowed down.

But if it were mine, with the noise I hear right there...... yeaaaahhhhh.... I've heard too many rod knocks in my day to not have a pit in my stomach as I listen to that.

I hope I'm wrong.

Let us know what you find?

The truth is that it's really hard to distinguish one sound from another in a video clip. I could be way off base.
But that rhythm.....

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piper6909 · 05-16-2019, 07:12 PM

I'm a newbie to Porsches, but this doesn't sound like an internal nor peripheral noise to me. It definitely doesn't sound like a rod knock to me. A rod knock has a constant rhythm and is much deeper, hollow sound, not an arrhythmic knock like what I'm hearing in the video. And water pump & alternator bearings tend to make a whining or howling noise. How does it idle? What I'm hearing is something on the motor knocking against something on the body. Combination of a rough idle and a bad motor mount could cause that noise.

Or it could be a bad serpentine belt tensioner slapping around. Removing the belt, as suggested by the earlier posts, is a good start and if it's the tensioner the noise will go away.

Good luck and please update us with your findings.

maytag · 05-16-2019, 08:12 PM

Quote:

Originally Posted by piper6909

It definitely doesn't sound like a rod knock to me. A rod knock has a constant rhythm and is much deeper, hollow sound, not an arrhythmic knock like what I'm hearing in the video.

Given that statement, I'm not sure you've ever HEARD a rod-knock.
Give it a little gas, it'll catch the rhythm.... sometimes.... depends how bad it is... but at idle? Nah.... they ALL sound like that.
And your "deeper hollow" sound might make sense with an iron block.... not an aluminum one.

Like I said: hope im wrong. But all of that fits rod knock.

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Geof3 · 05-16-2019, 09:42 PM

Yeah, I’m with Maytag on this one. That would be an odd sound for a water pump or other peripheral to make. Not to say it can’t be, but that sounds like a rod knock or possibly a valve, but valves are usually more of a tic than chunky type sound. Hope we are wrong.

piper6909 · 05-17-2019, 02:55 AM

Quote:

Originally Posted by maytag

Given that statement, I'm not sure you've ever HEARD a rod-knock.
Give it a little gas, it'll catch the rhythm.... sometimes.... depends how bad it is... but at idle? Nah.... they ALL sound like that.
And your "deeper hollow" sound might make sense with an iron block.... not an aluminum one.

Like I said: hope im wrong. But all of that fits rod knock.

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I've owned and serviced many Subarus, I know the sound of a rod knock. Aluminum blocks, boxer engines. I may be new to Porsches, but I've heard many rod knocks.

It could be, but I don't think this sounds like a rod knock.

Also, if it was a rod knock he'd hear it while driving. He said he didn't.

I'm thinking tensioner.

But we'll see if/when he reports back.

Boxstard · 05-17-2019, 02:56 AM

It does not sound like accessories... how many miles on the engine?

piper6909 · 05-17-2019, 03:00 AM

This is what a classic rod knock sounds like. Skip to 1:25 on 1st video.

https://www.youtube.com/watch?v=DFeJFMkyElk

https://www.youtube.com/watch?v=e79c_-_hVa8

https://www.youtube.com/watch?v=DfJIpiQZtR4

maytag · 05-17-2019, 04:11 AM

Piper, dood, just like in another recent thread: you just don't know when to let go, man.
C'mon.... keep sending videos of sounds (think about THAT for a minute, Haha).... hell, he could have an exhaust leak for all we can tell from the video.

If your experience differs from mine, I guess we can leave it at that. The are as many types of rod knock sounds as there are rods that knock (se what I did there?). In my own (clearly less Subaru- centric than yours. For whatever that's worth) experience, when a rod knock is in its early stages, it sounds precisely like what we're hearing in that video. But, so could many other things sound precisely like what we're hearing in that video. (Like an exhaust leak)

But if your experience is different... I'm gonna be okay with that.
Let it go, and keep hoping for his sake that I'm wrong and you're right.

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Starter986 · 05-17-2019, 04:23 AM

Piper, I'm curious... did you pick up your Boxster because of your familiarity of the flat sixes? What inspired you to make the Bioxster purchase?

Cheers!

piper6909 · 05-17-2019, 04:24 AM

Quote:

Originally Posted by maytag

Piper, dood, just like in another recent thread: you just don't know when to let go, man.
C'mon.... keep sending videos of sounds (think about THAT for a minute, Haha).... hell, he could have an exhaust leak for all we can tell from the video.

If your experience differs from mine, I guess we can leave it at that. The are as many types of rod knock sounds as there are rods that knock (se what I did there?). In my own (clearly less Subaru- centric than yours. For whatever that's worth) experience, when a rod knock is in its early stages, it sounds precisely like what we're hearing in that video. But, so could many other things sound precisely like what we're hearing in that video. (Like an exhaust leak)

But if your experience is different... I'm gonna be okay with that.
Let it go, and keep hoping for his sake that I'm wrong and you're right.

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Dude, you have issues. First you question my experience, now you have your panties in a bunch because I provided examples rod knocks?

I don't need to prove you wrong. If I did, I would have corrected your statement that internal noises get louder when the engine warms up. From my experience it's quite the opposite because as the parts warm up they expand and tighten the gap.

I've already let go of the other thread. I didn't bring it up, you did. Maybe it's time you let go as well.

As I've said, it it doesn't sound like a rod knock to ME. But I didn't rule it out, in fact, I said it COULD be. It was not meant as a slight to you. It's not about you. I also said it doesn't sound like accessory bearings.

The guy asked for opinions on the noise and we all gave our 2 cents worth based on our experiences. That is precisely what these forums are for.

piper6909 · 05-17-2019, 04:31 AM

Quote:

Originally Posted by Starter986

Piper, I'm curious... did you pick up your Boxster because of your familiarity of the flat sixes? What inspired you to make the Bioxster purchase?

Cheers!

Hey Starter. It was actually a gift for my wife. She always wanted one, and the Boxster is probably the only Porsche we afford.

I may be crucified for saying this, but I was never a fan of Porsches. I always thought of them as over-priced Volkswagens. LOL

Boy was I wrong. In a very short time I fell in love with that car!

KRAM36 · 05-17-2019, 04:58 AM

Quote:

Originally Posted by maytag

hell, he could have an exhaust leak for all we can tell from the video.

Yep or a dead lifter.

jrgill · 05-17-2019, 05:19 AM

I appreciate everyone's feedback and I plan to take your investigative advice first before putting it onto the car carrier and bringing it to my indie. I suspect I'll have time either Saturday or Sunday to pull the covers and begin the initial inspection. Once done, I'll report back with what I have found. Again, thanks to all!

Joe

nicecar · 05-17-2019, 06:00 AM

had that noise after driving.... if i depress clutch it goes away,happens ocassionaly for 7 years .Indy mentioned something about clutch?

Starter986 · 05-17-2019, 06:12 AM

Quote:

Originally Posted by piper6909

Hey Starter. It was actually a gift for my wife. She always wanted one, and the Boxster is probably the only Porsche we afford.

I may be crucified for saying this, but I was never a fan of Porsches. I always thought of them as over-priced Volkswagens. LOL

Boy was I wrong. In a very short time I fell in love with that car!

Likewise! Although my wife is frightened of the Box because, well, you actually have to drive it. Not like the Edge... the couch on wheels.

The Volkswagen comment, lol. In 94 I passed a lot that had a one-owner 86 325es for sale. "That" wife wanted to look at it... we did... and I told her it looked like an expensive Ford Escort (I had purchased a new Escort in 89). Well, a couple of weeks later I bought it with 218K on the clock, and for $5,400. Still have it and, the last I drove it (6 years ago) it was at 290K.

The Boxster I purchased was an impulse buy... saw it listed on CL (posted 3 hours before I saw it) and, 3 hours later... was driving it home. Never considered a Porsche... wasn't even on my radar! It looked so good!

Cheers!!!