2001 Boxster Engine Noise - Page 1 - Boxster/Cayman - PistonHeads UK

Ok, so a week ago I got my first Porsche. It is a 2001 Boxster (Base, not the S). I noticed after driving it that there is a vibration/rattle in the engine. It is quiet between idle up to about 2500RPM, between 2500 and about 4500 there is a distinct rattle. Now the rattle only occurs at or below 1/4 throttle. If I give it some stick it quietens out. Also on overdrive the noise is not there. I talked to my local Porsche rep and he scared me saying it could be IMS bearing. I probably put 100+ miles on the car with the vibration and it 't an hasn't gotten any better or worse, so I am guessing it isn't the MIS as my engine hasn't exploded. From what I hear once you hear the IMS the engine is about to blow up? The car has only 47,000 miles. I think it had sat at the dealer for a few months with little use. when I picked it up it had a dead battery. I am thinking it could be injector, or even an exhaust noise but am not sure what steps to take. I removed the ribbed belt (looked brand new) and the sound persisted, so I know its not from a pump or alternator. The sound happens in the garage as much as it does on the road. I will take it to Porsche to look at if I have to, but the local dealer is 50+ miles away. Anyone have any tips on what I can try? The dealer claimed it has fresh oil 0W40. Sorry for the long post but I want to know if I just wasted $13,00 on a ruined car, or if $15 of injector cleaner, or oil change will make the car sound like it should.

Could well be exhaust heat shields rattling. Quite a common problem, I had this on my Boxster. On mine it was more of a problem when the engine was cold. An easy fix, just need a dab of weld!

I would get a second opinion. It could be a multitude of things many of them not too serious.

Sounds very much like the rattling heat shields as suggested above. Of course a second opinion is always prudent but in the mean time, lay under the rear of the car, you have the central exhaust and back box which then goes of either side to two smaller cylinders. Above these you will find thin steel covers, just resting on top. Give them a poke and if they move then they have become loose or like both my cars, the bracket has rusted and let go. This will cause the rattle and noises at the rpm you have described. Couple of solutions, tack weld back on, if you can find good metal, try a new nut and bolt or fixing or....take them off altogether. Both of mine run without the heat shields and the effects? Nothing, one has not had them on for 4 years a 60 k. Your choice but eitherway take a quick look before paying out any cash.

I did take a poke around at a few heat shields but more to the rear of the car. I will look at the ones further forward today. Do I need to take the underbody fairings off to find the heat shields you mentioned? Thanks, Liam

No covers need to be removed. So lay under the car so the actual single tailpipe you can see, now look back and you will see the largest part of the exhaust system, the back box. From either side, left and right it becomes short tubes which then go to large cylinders, about the width of your forearm and twice the length of a coke can. It's above these that the shields locate. They are semi circular in profile, as if you'd cut a coke can down the centre, like gutters on a roof. Just grab a hold and any movement will cause an audible rattle. Mine were so loose I literally twisted them off. See how you get on.

On this pic they are located above the cylinders highlighted by the green arrows. Good luck, hope its these cos it's quick and cheap to fix!

Ok, so I put the car up on my ramp and gave al the heat shields a go. No joy there really, no play. I did notice if I hit the exhaust pipes there is a slight rattle in one of the pipes on the passenger side. Sounds almost like the noise a pop-can makes if there is a small stone in it. Sounds like it is coming from inside the can shaped part of the exhaust after what I assume is the Cat. Looks like the pipe is wrapped in a heat shield here, should possibly be the heat shield is loose, but I cant feel any vibration, and if I hold it and hit it the vibration is unaffected. Would such a small vibration be so loud at 3000-RPM or am I looking for something bigger? I am very nervous about this IMS bearing idea, do these things slowly go out or is it more of a catastrophic failure? The car idles sweetly and has no noise over 1/4 throttle, or on overrun. I imagine if a bearing was chewing apart it would be noisy regardless of RPM or throttle?? Edited by w6grace on Monday 2nd December 01:56

Have to agree with that. Common sense would state that like a wheel bearing you would hear a grinding or dull knocking possibly? Cats maybe breaking down? Reckon you need a second/mechanics opinion here but as cmoose states, if it was the IMS then you'd probably know all about it by now.

Ok, well I did notice a stronger than normal (Normal being my 2013 Ford) fuel smell when the car is running. Could this be a CAT issue, or maybe something with the injectors? The car only did 4,000 miles/year so I am thinking there could be gunk in several places, to include lifters... I am going to run some cleaner through it to clear that out. I would think a failing CAT wuld give me a CEL, no? I'll probably take it to the mechanic once it stops snowing, but I would like to resolve it before handing out $$$ for a mech to tell me something I should be able to figure out myself...

After another run tonight and another listen at idle all around the car I think its something inside the exhaust resonating. At idle it clicks 3 times then pauses 3, clicks 3, pauses 3. I am going to have to locate the exact spot of the vibration on my ramps and then replace the offending part. Now the question is do I get rid of the CATs if one has failed, or just replace the failed one? Are CATs for the Boxster about the same price as a ACT bypass kit? I really hate the sound of the car around 3,000 RPM, sounds like I am suddenly in a diesel buss.... Luckily with all the snow and cold weather I am not really missing much!

After another run tonight and another listen at idle all around the car I think its something inside the exhaust resonating. At idle it clicks 3 times then pauses 3, clicks 3, pauses 3. I am going to have to locate the exact spot of the vibration on my ramps and then replace the offending part. Now the question is do I get rid of the CATs if one has failed, or just replace the failed one? Are CATs for the Boxster about the same price as a ACT bypass kit? I really hate the sound of the car around 3,000 RPM, sounds like I am suddenly in a diesel buss.... Luckily with all the snow and cold weather I am not really missing much!

Well I have some sad news today, after owning the car one week she blew up on me today... I am guessing it was the IMS as it suddenly started bucking and the engine sounded like someone added a bunch of coins to my oil. I am hoping the dealership will take it back as one week is unacceptable as far as reliability, even in a used car! I only got 300 miles in. I am guessing that the previous owner knew there was a noise in the bearing and traded it in on an unsuspecting dealership... I was wondering what would make someone sell a perfect condition 2001 Porsche with only 47k on it...

Fookin Hell! A rattle in the exhaust to a lunched engine, that's not good. If you have a full warranty then all hopefully will be fine, keep us posted.

Unfortunately I was still shopping around for a warranty. I was supposed to get a call back today to pick the plan... I hope the dealership steps-up and at the least offers to take the car back. There is a small possibility it was something like a water pump that blew and thus caused the noise and resistance on the engine.... Small hope though as I had pulled the belt last week and the vibration persisted. Is it possible that something collapsing in the CAT could cause the engine to stutter, maybe if it became blocked? Small hope I know...

Sorry to hear this. Its unfortunately a spectre that hangs over the head of all owners of models prone to ims failure. Hope you get it resolved with the selling dealer.

I understand that it is a risk item to the car, but the fact that it failed within 300miles of me getting the car makes me think it was a pre-existing condition that the previous owner knew about and traded the car in. I unfortunately hadn't gotten around to getting the aftermarket warranty yet, was going to be doing that today... Well I just hope that its either something not as bad as an IMS (it sounded terrible), or the dealer will be honorable and take the car back. I believe the state of Washington requires a 90day no major failures type warranty of all cars sold, so I may even get a new engine out of the deal... I'll post again today when I hear back from them as to what the damage is.

So the dealer is honoring the sale by offering to take the car back and to get me a equal value replacement. Now the search is on for a low miles boxster in the Seattle area, or some other fun 2 seat soft top... I had just started to love my boxster...

That sounds to be about the best outcome you could have wished for. I'd wait for another Boxster - anything else would be a dissapointment.

Well after a few weeks and the car bouncing to 3 different shops for quote it turns out that it was not an IMS. Aparently one of the chain tensioners failed. Luckily it just loosened the chin enough to make noise and mess with the idle, but no actual engine damage! The dealer is paying the $7,000 to have all the work done and I should have my caar back in a week or two!