Mysterious engine noise / squeak...$$$$

[kamran66]

Hi folks, my Boxster developed a chriping squeaking sound a few weeks ago...so far I replaced the AOS, accessory belt and two idler pulleys with no effect. I had the car taken to a local mechanic we attempted to listen to it to pinpoint the noise but we only isolated it to the right hand side towards the front. I shook the lines and hoses from the top and when shook the AOS the sound changed, that and the white smoke led me to believe it was the AOS so I replaced it (2nd one, last changed 2005)...well needless to say NO JOY :( The "chic..chic" sound is still there, it sounds like a pulley or bearing..it's heard best during idle and when I step on the gas it can be heard getting faster up to 2000 RPM. If anyone has any ideas I'd be greatly appreciated it....

Regards,

Kamran

00 Boxster (100k club)

[Loren]

A "chirp" sound is usually a loose spark plug - have you checked those?

If not the spark plug then remove the polyrib belt and check each pulley for wobble and/or squeaks. Replace any that exhibit those symptoms.

[pk2]

The belt would have been my first guess but you've done your due diligence. If not the spark plugs, I've heard the lifters in higher mileage motors can give a chirp for a bit while warming up.

You also mentioned in passing late in your paragraph white smoke. That can be a bad thing and should share top billing on your post… Speak.

Regards, PK

Edited June 27, 2010 by pk2

[kamran66]

The belt would have been my first guess but you've done your due diligence. If not the spark plugs, I've heard the lifters in higher mileage motors can give a chirp for a bit while warming up.

You also mentioned in passing late in your paragraph white smoke. That can be a bad thing and should share top billing on your post… Speak.

Regards, PK

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Thanks Loren, PK, I will check the spark plug to see if it's the culprit...also to answer the white smoke query, I thought it was just another clue into the 4 yr old AOS failing..? it only smoked after the car was parked on the inclined ramp of a parking garage and only when the car was left parked for 2 or more days.

Regards,

Kamran

[Wayne R. Dempsey]

I'll take a wild stab and maybe say vacuum leak from one of the hoses that feeds the AOS? Use a smoke machine maybe to check for vacuum leaks - at least that way you can eliminate the potential for that issue. Problems like these are difficult to solve with the car right in front of you, let alone over the Internet (vacuum leak check article I wrote here: http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm)

-Wayne

[kamran66]

Loren, once again you're spot on....good show. After changing the aformentioned parts with no effect we found a slightly loose spark plug (and I mean slightly less than 1/2 turn) on the right hand cylinder bank. No more chic...chic rubbing sound. Thanks Loren, PK and Wayne.

[dr_smith]

I want to thank Loren and kamran66. I had the repetitive squeak coming from behind the driver's side of the engine (Boxster 986 2002). Sounded so much like a bearing BUT...turned out to be a loose spark plug in the middle cylinder. I had trouble believing it as have owned the car for over a year now and the squeak developed only a couple months ago. The car ran well, not rough, and there is no noticeable smoke coming from the exhaust. However here's the story. Hopefully will save others lots of time and money troubleshooting this elusive problem.

Before reading any forums I removed the rear panel and figured it was coming from either the A/C compressor or the power steering pump. I chose to replace the power steering pump ($200+) which was a mini nightmare in itself. Still the squeak was present. I researched the A/C compressor and learned you can't just purchase the A/C clutch separately and the compressor is around $600 or $300 for after market, rebuilt, but removed the A/C clutch anyway and the bearing seemed smooth and not an issue. I then replaced the top idler roller ($100+), even though it turned by hand smoothly but had just a slight noise that the other two rollers didn't. Still the squeak. I finally researched by googling, "Squeaky noise from engine compartment Porsche boxster 2002" and read this and other forums on the subject. One forum had the link to Youtube with the exact sound so I knew I was closing in on it. In one forum, it was suggested to eliminate all the items driven by the serpentine belt simply by removing the belt and running the car for a minute. If the sound persists, it's NOT the items turned by the belt (A/C, Power Steering pump, Water pump, Alternator, Idler rollers/tensioner). What a useful hint! I tried this and the sound persisted so I focused on the engine. Please NOTE: in Park the sound was not there. I had to load the engine slightly by placing in Drive or Reverse; e-brake on of course. However, back to the forums, besides mentioning loose spark plugs, the forums had many members writing that it must be the AOS (air oil separator). Not being a mechanic or even Porsche mechanic for that matter, I had to locate the AOS and could see it was opposite where the sound came from. Also, no smoke was coming out so really doubted the AOS. I decided to change the plugs and hopefully get lucky if one is loose and BINGO, the second plug I removed could be turned out by hand only. I could scarcely believe it. Replaced it and tightened to 22 ft-lbs and sound gone! Turns out, 4 of 6 plugs were loose and only one was torqued to over 40-50 ft-lbs!! Wondering who worked on the car before?? Or is this something that just happens with Boxster 986's?

[Mark St Martin]

Just want to say thank you to this forum, once again helped with a mystery.

I would have never believed this if I didn't see it for myself, a loose plug!!

And to add to this topic, let's also describe it as a "chirping" sound.

I've heard of engines blowing out a loose plug (threads and all) ... has this ever happened to a Boxster or any flat 6?

Thanks again!! it had me worried =]

Edited October 1, 2021 by Mark St Martin
spelling =p

[Loren]

[Mark St Martin]

My gosh, I feel like an expert now 😜 a 2001 black Boxster S has come available to me.

The owner pulled up in front of my shop with a worry of a pulley or such letting go.

Sure enough the chirping sound was there, no different from my '97  2.5

Confident I put her up on my hoist and there it was plugs 1 & 2 where loose.

Now I have the weekend to enjoy this 5spd stnd 3.2,  then decide if it's worth buying ...

It doesn't quite present as nice as my older Tiptronic but it is a stick  😊

[JE 17]

5 speed Boxster S??

[Mark St Martin]

Well JE17, that's what I thought ... after one day I knew it wasn't for me.

 

Visually, the one really nice thing it had was a set of 19" black rims with the chrome inserts.

The not so nice one thing was an additional wing (non Porsche) with brake light. In fact that would have been the first thing to go!!

 

Taking it out for a ride it was extremely loud and quite frankly, I'd much rather drive my 97' Tiptronic!!!

The exhaust was modified, the muffler was removed with two straight pipes exiting the rear, and I thought mine was loud 😖

After pulling out my Bentley book I discovered much about his as well as mine.

Yes he's been driving what he thought is an "S" without all extras an S should have had such as a 6 speed stick.

Amongst a myriad of other issues, an 01' for $7900us with over 124,000 miles, too much for me.

 

But the good thing, the chirping is gone =p 

[Turbo doug]

Thanx everyone what sounded like a chirping u joint or belt or bad bearing was indeed 1 very loose spark plug chiping louder at low acceleration