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Engine knocking due to Clutch Bearings?


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hi all,

'01 S w/ 43,500K mi

I noticed engine knocking noises when I stepped out of my car one day - at idle*. I took it in for an oil change at a friends shop, and he felt 100% sure it was a loose exhaust. However, wanting to cover all bases, I took it into the dealer. The rep immediately suspected my clutch, and sure enough when he pressed it in, the knocking subsided. His explanation was that there is a single bearing that is apparantely drying-out and once it fails the clutch will be useless. He stated that he was 90% sure that was the problem, and it would be approximately $1800 (on the high side) to get it replaced. He said to determine if the that is truly the problem, they would need to take out the transmission at a cost of $1100.

After hearing the noise stop by pressing the clutch, I suspect he is right, but would really like eveyones input here. If indeed this is the situation, what would happen if I continue to drive until it fails. Will I simply lose the clutch and have to get it replaced, or can there be more catastrophic damage? Truly, I don't understand the mechanics involved, nor really know my options.

Thanks in advance.

* I need to add that when I turn off the engine, it quickly knocks 3-4 times before it shuts off.

Edited by por986
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It seems like, it is the thrust bearing. At idle with the engine running but not moving and the car in NEUTRAL press down the clutch pedal and repeat this a few times. When u pump the pedal if the sound changes, most likely you have a knackered thrust bearing. Probably had all the way to its minimal wear. its hard to damage anything any further at this point, but most likely your clutch assembly is already damaged, And YES in order for u to be sure- the thrust bearing needs to be inspected visually which requires a removal of your transmission. If your dealer quoted u $1800 thats is pretty cheap! Because when u need a new thrust bearing , u will also need a clutch job-100% recommended. Usual DEALER cost is around $3000.00. But if u r a bit handy, with Renntech club member's help I'm sure U can possibly repair this problem in a few days(HOPING). I recommend you to replace the whole clutch assembly. It saves a whole lot of mucking about later.

hi all,

'01 S w/ 43,500K mi

I noticed engine knocking noises when I stepped out of my car one day - at idle*. I took it in for an oil change at a friends shop, and he felt 100% sure it was a loose exhaust. However, wanting to cover all bases, I took it into the dealer. The rep immediately suspected my clutch, and sure enough when he pressed it in, the knocking subsided. His explanation was that there is a single bearing that is apparantely drying-out and once it fails the clutch will be useless. He stated that he was 90% sure that was the problem, and it would be approximately $1800 (on the high side) to get it replaced. He said to determine if the that is truly the problem, they would need to take out the transmission at a cost of $1100.

After hearing the noise stop by pressing the clutch, I suspect he is right, but would really like eveyones input here. If indeed this is the situation, what would happen if I continue to drive until it fails. Will I simply lose the clutch and have to get it replaced, or can there be more catastrophic damage? Truly, I don't understand the mechanics involved, nor really know my options.

Thanks in advance.

* I need to add that when I turn off the engine, it quickly knocks 3-4 times before it shuts off.

Edited by juniinc
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hi all,

'01 S w/ 43,500K mi

I noticed engine knocking noises when I stepped out of my car one day - at idle*. I took it in for an oil change at a friends shop, and he felt 100% sure it was a loose exhaust. However, wanting to cover all bases, I took it into the dealer. The rep immediately suspected my clutch, and sure enough when he pressed it in, the knocking subsided. His explanation was that there is a single bearing that is apparantely drying-out and once it fails the clutch will be useless. He stated that he was 90% sure that was the problem, and it would be approximately $1800 (on the high side) to get it replaced. He said to determine if the that is truly the problem, they would need to take out the transmission at a cost of $1100.

After hearing the noise stop by pressing the clutch, I suspect he is right, but would really like eveyones input here. If indeed this is the situation, what would happen if I continue to drive until it fails. Will I simply lose the clutch and have to get it replaced, or can there be more catastrophic damage? Truly, I don't understand the mechanics involved, nor really know my options.

Thanks in advance.

* I need to add that when I turn off the engine, it quickly knocks 3-4 times before it shuts off.

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hi all,

'01 S w/ 43,500K mi

I noticed engine knocking noises when I stepped out of my car one day - at idle*. I took it in for an oil change at a friends shop, and he felt 100% sure it was a loose exhaust. However, wanting to cover all bases, I took it into the dealer. The rep immediately suspected my clutch, and sure enough when he pressed it in, the knocking subsided. His explanation was that there is a single bearing that is apparantely drying-out and once it fails the clutch will be useless. He stated that he was 90% sure that was the problem, and it would be approximately $1800 (on the high side) to get it replaced. He said to determine if the that is truly the problem, they would need to take out the transmission at a cost of $1100.

After hearing the noise stop by pressing the clutch, I suspect he is right, but would really like eveyones input here. If indeed this is the situation, what would happen if I continue to drive until it fails. Will I simply lose the clutch and have to get it replaced, or can there be more catastrophic damage? Truly, I don't understand the mechanics involved, nor really know my options.

Thanks in advance.

* I need to add that when I turn off the engine, it quickly knocks 3-4 times before it shuts off.

I don’t know the specifics of these thrust bearing. I do know that your essentially looking at a complete clutch job. There aren’t really many things to go wrong with clutch mechanism. Parts including your bearing are as low as $354 (oem, Sun Coast). That’s gonna cover everything that might be amok in there.

Personally, depending on the size of your town, I’d check with an established independent Porsche or German auto repair shops. Ask them there price for new clutch, then say by the way…

Dealers offer absolutely nothing a good independent can. They just cost a elluva lot more. Dealers make a large % of their overall profit on service. Your repair bill is keeping the showroom sparkling.

Regards, PK

Edited by pk2
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LOL, PK

hi all,

'01 S w/ 43,500K mi

I noticed engine knocking noises when I stepped out of my car one day - at idle*. I took it in for an oil change at a friends shop, and he felt 100% sure it was a loose exhaust. However, wanting to cover all bases, I took it into the dealer. The rep immediately suspected my clutch, and sure enough when he pressed it in, the knocking subsided. His explanation was that there is a single bearing that is apparantely drying-out and once it fails the clutch will be useless. He stated that he was 90% sure that was the problem, and it would be approximately $1800 (on the high side) to get it replaced. He said to determine if the that is truly the problem, they would need to take out the transmission at a cost of $1100.

After hearing the noise stop by pressing the clutch, I suspect he is right, but would really like eveyones input here. If indeed this is the situation, what would happen if I continue to drive until it fails. Will I simply lose the clutch and have to get it replaced, or can there be more catastrophic damage? Truly, I don't understand the mechanics involved, nor really know my options.

Thanks in advance.

* I need to add that when I turn off the engine, it quickly knocks 3-4 times before it shuts off.

I don’t know the specifics of these thrust bearing. I do know that your essentially looking at a complete clutch job. There aren’t really many things to go wrong with clutch mechanism. Parts including your bearing are as low as $354 (oem, Sun Coast). That’s gonna cover everything that might be amok in there.

Personally, depending on the size of your town, I’d check with an established independent Porsche or German auto repair shops. Ask them there price for new clutch, then say by the way…

Dealers offer absolutely nothing a good independent can. They just cost a elluva lot more. Dealers make a large % of their overall profit on service. Your repair bill is keeping the showroom sparkling.

Regards, PK

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So sorry to hear of your clutch problem. Hopefully the damage is contained to the clutch area and will be easy to repair. With all of the knocking noises that have taken place I would consider, if it was my car, not trying to run the car until it has been disassembled and checked for damage. I would have it put on a flat bed and delivered to the repair site. Ask a local Porsche repair expert on 986's for his advice before attempting to drive the car. Preferably the one who will do the physical work.

Best of luck with the repair.

qtwo

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Thank you for the replies. Just my luck! I was hoping for something like, "just WD40 themthere shoe torques and uh well, you'll be right as rain!" :-\

Again, not knowing about the mechanics here, It seems odd to me that I wouldn't notice something through the pedal or durning shifting (explanation would be appreciated). Aside from the noise, it seems all good.

Attached is an audio clip.. knocking.mp3

At 8-9 seconds, I press the clutch and you can here it goes away, then at 12 seconds when I release the clutch, it comes back with a vengeance. And then you can here the knocking when the engine is shut off.

So, from what I gather, I can just keep drivn until it fails huh without damaging much more (because I will replace the entire clutch (included in that $1800)?

BTW, I am in the San Antonio and Austin area (TX), so if you know of anyone in these parts, please point me in their direction. Also, I may be heading to Burbank California in late Dec or early January, so maybe someone there?

edit: The rep did say that I might get another 10K out of it (more or less) - as it is hard to tell without breaking things open to see the amount of wear.

"Life is tough, but it's tougher when you're stupid." - John Wayne

Edited by por986
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liked that MP3 audio clip u inserted ,pretty cool!

u probably will get another 5k-10k it souldnt hurt your engine or tranny

Good luck.

Thank you for the replies. Just my luck! I was hoping for something like, "just WD40 themthere shoe torques and uh well, you'll be right as rain!" :-\

Again, not nowing about the mechanics here, It seems odd to me that I wouldn't notice something through the pedal or durning shifting (explanation would be appreciated). Aside from the noise, it seems all good.

Attached is an audio clip.. knocking.mp3

At 8-9 seconds, I press the clutch and you can here it goes away, then at 12 seconds when I release the clutch, it comes back with a vengeance. And then you can here the knocking when the engine is shut off.

So, from what I gather, I can just keep drivn until it fails huh without damaging much more (because I will replace the entire clutch (included in that $1800)?

BTW, I am in the San Antonio and Austin area (TX), so if you know of anyone in these parts, please point me in their direction. Also, I may be heading to Burbank California in late Dec or early January, so maybe someone there?

edit: The rep did say that I might get another 10K out of it (more or less) - as it is hard to tell without breaking things open to see the amount of wear.

"Life is tough, but it's tougher when you're stupid." - John Wayne

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U can do it! I'm sure that many of us here are willing to help u, if its necessary.

I am so sad. So, do you think that a complete novice can do this repair or am I asking for some real trouble?? I did install rear speakers :D

Thanks for the encouragement! This may very well become my first REAL project.

To get started, can you point me in the right direction for the parts I should be looking for? Just to begin my research.

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Clutches are the tie between the engine and the transmission. They make it possible to comfortably start from a standstill and they interrupt the flow of power between the engine and the transmission when changing gears or idling. They are mainly made up of a clutch disc, clutch cover and releaser, although various constructions do exist depending on application needs. All clutch components have been tuned to reach the same life span. In the event that a clutch component breaks down, it is strongly recommended that the entire clutch is replaced. For this reason, ZF Trading has created the ideal solution with the complete kit product range; made up of a clutch cover, clutch disc, and releaser. The kit includes the special grease required for fitting and problem-free operation.

U can do it! I'm sure that many of us here are willing to help u, if its necessary.

I am so sad. So, do you think that a complete novice can do this repair or am I asking for some real trouble?? I did install rear speakers :D

Thanks for the encouragement! This may very well become my first REAL project.

To get started, can you point me in the right direction for the parts I should be looking for? Just to begin my research.

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I am so sad. So, do you think that a complete novice can do this repair or am I asking for some real trouble?? I did install rear speakers :D

Don't be sad. Take a look at a recent post by "jporter" (use the "search" link at the top right of the page and put in the name "jporter" in the correct box).

That thread will give you an idea, along with some helpful photos, as to what it takes to remove and reinstall the transmission, which is what you must do to replace the clutch components. "jporter" wrote the procedure regarding his experiences with the oil leaks in his Boxster, but the same procedure applies. While you are at it, you will have a good opportunity to inspect the RMS.

I agree that with enough help from this board, even a novice ( a determined novice) can replace a clutch on a Boxster.

Regards, Maurice.

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Aside from the generous help offered here, will the bentley porsche shop manual provide all the direction needed to continue? Does it outline the tools necessary as well?

Thanks.

The Bentley Manual has a chapter devoted to removing and reinstalling manual transmissions (5 and 6 speed), which is reasonably detailed. They do not give you a list of the tools needed, but there is good information contained there regarding the torque values of the various fasteners for re-installation. From my experience, I can tell you that you shouldn't do this without a torque wrench.

They mention a special Porsche tool (or equivalent) for suspending/supporting the engine while removing the transmission, but, again, "jporter" used a 2X4 to accomplish the same task. IIRC, he wasn't too happy with the 2X4 setup, but it worked. You will also need some kind of a jack to support and lower the transmission with some control.

Did you look a the jporter thread? If you can't find it, let me know and I will hunt it down and post the link.

Regards, Maurice.

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Aside from the generous help offered here, will the bentley porsche shop manual provide all the direction needed to continue? Does it outline the tools necessary as well?

Thanks.

...

Did you look a the jporter thread? If you can't find it, let me know and I will hunt it down and post the link.

Regards, Maurice.

If it is the post regarding the oil leaks (http://www.renntech.org/forums/index.php?showtopic=15683&hl=jporter+transmission), yes. Thank you.

Being a novice, it looks all foreign to me, but I am excited to 'potentially' do this - if it turns out to be cost effective. I am going to a shop today to see what they will charge, but I suspect I will be on the better doing it myself. Not to mention I have ALWAYS wanted to delve in mechanics, but have simply been scared due to the unkown. With support like what I have found here on Renntech, it makes it seem very doable.

If it turns out to be something that I tackle, I really do intend to document all the steps from a beginnner's POV. It might help someone else out there who is on the fence like me.

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Aside from the generous help offered here, will the bentley porsche shop manual provide all the direction needed to continue? Does it outline the tools necessary as well?

Thanks.

...

Did you look a the jporter thread? If you can't find it, let me know and I will hunt it down and post the link.

Regards, Maurice.

If it is the post regarding the oil leaks (http://www.renntech.org/forums/index.php?showtopic=15683&hl=jporter+transmission), yes. Thank you.

Being a novice, it looks all foreign to me, but I am excited to 'potentially' do this - if it turns out to be cost effective. I am going to a shop today to see what they will charge, but I suspect I will be on the better doing it myself. Not to mention I have ALWAYS wanted to delve in mechanics, but have simply been scared due to the unkown. With support like what I have found here on Renntech, it makes it seem very doable.

If it turns out to be something that I tackle, I really do intend to document all the steps from a beginnner's POV. It might help someone else out there who is on the fence like me.

That's the correct post.

Since you have never done this before, in order not to get overwhelmed by the "unknown", just keep in mind what it is you will actually be doing when you tackle the job. You are essentially unbolting the transmission from the engine, then unbolting the pressure plate from the back of the transmission, replacing the clutch disc, throwout bearing and pressure plate, and then re-attaching the transmission to the engine. Not very complicated, really, but it does require patience, a decent workspace and the right tools to make the job easier.

My experience is also, that if you are not under pressure to get the car back on the road (i.e., you have other transportation), it always makes the job much more relaxed and enjoyable.

Curious to hear what the shop wants to charge, but I think you have the right attitude. Documenting it with lots of photos will not only help others in the future, but it will help you keep track of what goes where and to get help if you get hung up on something.

Regards, Maurice.

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That's the correct post.

Since you have never done this before, ...

...Regards, Maurice.

So I just got back from the shop. Very nice and knowledgeable owner. His price is $495 for the parts, and $600 and some change for labor (totalling around $1100). Sounds like a good option. However, on the way home I stopped by a maintenance shop where some of my friends work and I asked them that if I was willing to get my hands dirty, how could they help me out. They offered their shop, tools, and guidance. They work mainly on domestic cars and Japanese vehicles, but are very confident nonetheless. What more could I ask for?

Either way, I guess this would be a good time to upgrade the assembly. I feel like the a stock replacement would be foolish. The SACHS one that Juniinc posted sells for $319.95 in Performance Products catalog. I see other upgrades online that claim to have benefits over the stock option like "clamping force increase of 21 percent" but what does that really equate in driveability? Again, novice here ;)

Whatever the case, I really want to get to know my porsche versus just being a driver, so this might all be a blessing in disguise. I will keep you posted on the route I end up taking.

BTW, thank you very much for the watered down explanation. I really needed that to visualize things better.

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So I just got back from the shop. Very nice and knowledgeable owner. His price is $495 for the parts, and $600 and some change for labor (totalling around $1100). Sounds like a good option. However, on the way home I stopped by a maintenance shop where some of my friends work and I asked them that if I was willing to get my hands dirty, how could they help me out. They offered their shop, tools, and guidance. They work mainly on domestic cars and Japanese vehicles, but are very confident nonetheless. What more could I ask for?

Either way, I guess this would be a good time to upgrade the assembly. I feel like the a stock replacement would be foolish. The SACHS one that Juniinc posted sells for $319.95 in Performance Products catalog. I see other upgrades online that claim to have benefits over the stock option like "clamping force increase of 21 percent" but what does that really equate in driveability? Again, novice here ;)

Whatever the case, I really want to get to know my porsche versus just being a driver, so this might all be a blessing in disguise. I will keep you posted on the route I end up taking.

BTW, thank you very much for the watered down explanation. I really needed that to visualize things better.

With your friends' shop, you have certainly found the ideal way to "get to know the car better."

Unless you track your car, I don't know that the "21 percent increase in clamping force" would be of any use to you. I'll let others with more experience in that arena comment on that aspect. You might search on some other forums that have more emphasis on the racing scene for Boxsters to see what you can learn about high performance clutch setups, etc...

After you finish the job, along with the tremendous feeling of satisfaction that you will experience, take the $700 to $800 savings and buy something nice for you and your Boxster.

Regards, Maurice.

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SACHS grip force would be just fine!

So I just got back from the shop. Very nice and knowledgeable owner. His price is $495 for the parts, and $600 and some change for labor (totalling around $1100). Sounds like a good option. However, on the way home I stopped by a maintenance shop where some of my friends work and I asked them that if I was willing to get my hands dirty, how could they help me out. They offered their shop, tools, and guidance. They work mainly on domestic cars and Japanese vehicles, but are very confident nonetheless. What more could I ask for?

Either way, I guess this would be a good time to upgrade the assembly. I feel like the a stock replacement would be foolish. The SACHS one that Juniinc posted sells for $319.95 in Performance Products catalog. I see other upgrades online that claim to have benefits over the stock option like "clamping force increase of 21 percent" but what does that really equate in driveability? Again, novice here ;)

Whatever the case, I really want to get to know my porsche versus just being a driver, so this might all be a blessing in disguise. I will keep you posted on the route I end up taking.

BTW, thank you very much for the watered down explanation. I really needed that to visualize things better.

With your friends' shop, you have certainly found the ideal way to "get to know the car better."

Unless you track your car, I don't know that the "21 percent increase in clamping force" would be of any use to you. I'll let others with more experience in that arena comment on that aspect. You might search on some other forums that have more emphasis on the racing scene for Boxsters to see what you can learn about high performance clutch setups, etc...

After you finish the job, along with the tremendous feeling of satisfaction that you will experience, take the $700 to $800 savings and buy something nice for you and your Boxster.

Regards, Maurice.

Edited by juniinc
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Go for it but be realistic. It's not a good first or 2nd DIY job.

I am in the middle of a clutch replacement. Getting to the trans is the hardsest part, so far. You have to drop the exhaust, underbody bracing, cv joints....Expect to take your time. If your car is newer and not rusty, it will be a lot easier. My exhaust was rusty and all the bolts had fused together. So it has been slow going. But you'll learn a lot. If you do this most other jobs are easy.

That said $1100 for a clutch is not bad at all.

I didn't read the whole post but if you only have a noise, check for a loose spark plug.

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Go for it but be realistic. It's not a good first or 2nd DIY job.

I am in the middle of a clutch replacement. Getting to the trans is the hardsest part, so far. You have to drop the exhaust, underbody bracing, cv joints....Expect to take your time. If your car is newer and not rusty, it will be a lot easier. My exhaust was rusty and all the bolts had fused together. So it has been slow going. But you'll learn a lot. If you do this most other jobs are easy.

That said $1100 for a clutch is not bad at all.

I didn't read the whole post but if you only have a noise, check for a loose spark plug.

Thanks for that input. I am really going back and forth on this. I mean, even the "experienced" Porsche service manager said he is ALMOST sure that is what it is. My biggest hesitation is that I go into it and once complete, the problem is still there. Because I don't know everthing to look for and I don't have the knowledge to properly inspect everything else while I am there, I may blindly neglect something that is sticking right out.

One thing that still confuses me, and no one has really explained clearly enough for me to understand is why the knocking noise when the clutch is not engaged? The most accurate things I have found is that in this scenario, the problem is most likely "an issue in the contact point between the fork and pivot ball". Still, I would love a detailed explanation as to how the knocking noise would be generated.

thanks.

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  • 3 years later...

Had to post an update - 3 years later :-\ <insert your jabs>

So I did it! My hand was forced due to an oil leak (RMS) after replacing my AOS. Today is the 4th day of driving after replacing Clutch, RMS and IMS and it is driving like new. Actually feels more powerful then I remember over the past 9 years.

It was a long road and it took me a few months because I could only spend a few hours per weekend and did a lot of driving here and there for tools and waiting for replies to questions as they came up.

IMS install is not documented *fully* anywhere as there are little gotchas here and there, and luckily, thanks to a few members and the interwebs, I was able to get it done. For anyone that has never worked on a car before but has enough ballz to give it a shot, you can do it. If you are in the San Antonio, TX area and need help doing a similar job, the dealer charges $160/hr in labor... I will beat them by 10 bucks/hr, so drop me a note ;) In all seriousness, it really wasn't that difficult - you are really paying for the know-how. I think that I could do the entire job now in 8hrs knowing the intricacies.

I still have some other things to take care of (CV boots)... maybe another 3 years...ha!. I have a makeshift RMS install tool to return to a member, and I just want to say to anyone that I have been in touch with thank you very much for the assistance.

Edited by por986
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