Scott2.0

Hi all, I'm about to drop my 02 S off for its "peace of mind" service. It's time for the clutch, so I'm doing the IMS retrofit as well. The RMS will be changed and I'm also being charged for cam bolts(?) and a flywheel bolt. They are telling me that unless the car is blowing out smoke that the AOS doesn't need to be replaced and the flywheel SHOULD be fine. Am I missing anything else that I should address now while it's opened up? The car has 75k miles.

Thanks!

paulofto

'While you are in there' .Regardless of what they say, with that mileage do the flywheel and AOS and consider the water pump as well. With the tranny out these are no brainers.

Scott2.0

They said that the water pump isn't in the same vicinity so there is no advantage to me doing it now versus on its own. The flywheel will add $800 to the job, so I'm somewhat reluctant, but you may be right. Is the AOS a wear item? If so, it would make sense to replace it at this time. Thanks!

mikefocke

The AOS is an age item. Some few last 20k, some few 100k. It is a situation where if you don't do it, it is more difficult, and expensive to do it without all the stuff pulled off to do the IMS. It can be done yourself. No special skills needed. A tool or two.

The water pump is a wear item, at least the bearing it rides on is. Yes it is on the other end of the engine. Doing it is a while you have the car there item, not a mandatory.

Cam bolts?? The cams are locked during the IMS procedure and not touched so ask for a bit more info on what these bolts are and why?

The other thing I'd consider is the engine mounts. They are like shock absorbers for the engine to frame connection. Rubber, ages, wears and eventually weakens and tears. If there has been any movement at all when you shift, consider them. Can be done later. But it is up on a lift so ...

And then you get to fluids. Brake fluid ages and picks up water which can corrode brake parts. How long since it was changed? Anti freeze? Ages and you would do it as part of the water pump replacement.

I could think of a couple of thousand dollars more in nice to do items but ...

Macster

If the RMS is leak free changing it could be asking for trouble. The new RMS needs to be installed at a different depth than the original RMS. If it is installed to the same depth then the part of the seal that touches the crank journal will end up right where the old seal touched the crank journal. The old seal has almost certainly wore a shallow groove in the crank journal and if the new seal is installed to the same depth the new seal will probably leak.

A non leaking RMS can go a long long time. My 2002 Boxster's RMS was replaced at 25K miles back in 2002 and was leak free at 317K miles, nearly 300K miles later.

I'm with Mike in that I don't know why cam bolts need to be touched. Unless maybe the shop was referring to the bolts that hold the IMSB end plate in place? Again though if this is not showing signs of leaking I'd be tempted to leave the end plate and bolts alone.

Kind of jumping around I can tell you if it looks like there is an RMS leak both the RMS *and* the IMSB end plate should be replaced. There is no way to know if the leak is from just the RMS. In fact when I have my Boxster in for a new RMS -- this under warranty too so it wasn't the dealer SM trying to pad the repair bill -- the SM told me it was the factory's policy to have the dealer replace both the RMS and the IMSB end flange (and bolts) with an updated flange (a 3 ribbed seal vs. a single o-ring) and better bolts (micro-encapsulated to seal the threads).

As for the flywheel if the friction surface is ok, does not have signs of overheating with the resulting hard spots which make the clutch hard to engage smoothly (and which won't get better with more use) and does not show any other signs of degradation (grooves, cracks), and if the flywheel passes a test which is used to flag a faulty dual mass feature the flywheel can be reused.

The flywheel can even be resurfaced and probably should be. (I have come upon Boxsters in for a new clutch and the (dealer) tech had sent the flywheel out to be resurfaced.) A resurfaced flywheel goes a long way to ensuring the clutch disc and flywheel friction surfaces develop a surface that is conducive to a long and trouble free clutch life.

At 75K miles based on my experience with 3 AOS's with my 2002 Boxster your car's AOS can be anywhere from 5K miles to 25K miles away from failure. Frankly a 2002 MY car with 75K miles my advice would be to have the AOS replaced. You should get some savings from having this done with the transmission out of the car.

If the car has had its coolant replaced every 4 years or so this can prolong the life of the water pump. My 2002 Boxster's water pump lasted 172K miles and failed due to bearing wearing out. So at 75K miles the water could have around 100K miles left. If the coolant has not been replaced every 4 to 5 years I'd be tempted to have the water pump and T-stat (with factory parts!) and of course the coolant replaced. Obviously the water pump/T-stat are at the other end of the engine so there's no real labor savings to be had but you get this taken care of along with every thing else and you do not have the inconvenience of having to bring the car in for just the water pump/T-stat at some later time.

At the same time the water pump/T-stat are replaced unless the serpentine belt is relatively new get a new serpentine belt installed.

If spark plugs are due to be replaced on miles or time get those done as well. I'm thinking the shop could (should) cut you a good deal on the labor of the spark plugs (and above the labor to replace the AOS) as the exhaust system should be out of the way and replacing the plugs (and AOS) is much less work.

Scott2.0

Wow, great advice, thanks all. I'll definitely add the AOS to the list and will ask for feedback on the condition of the flywheel once inspected. Good call on plugs too. That seems like a no-brainer add-on too.

I actually just bought the car today! I had already made the appointment with the shop before picking it up and factored the expense into the purchase. It may be overkill, but I'll sleep better knowing that the IMSB has been addressed and while it still holds just fine, it seems like the clutch might as well get knocked out at the same time.

Charles Navarro

I've put together a quick document on preventative maintenance.

With regards to the flywheel, it's likely bad. 9 out of 10 cars have bad flywheels when they go in for an IMS and RMS. There is a tester from Luk to quantify the required spring-back to qualify a DMF to be in spec. Unless it's been tested, don't assume it's still good is the moral of the story. If the shop doesn't know there is a tester for this or that they need to test it, find a new shop.

Always update the RMS while you are in there with the newest Genuine Porsche one.

Likewise, the water pump needs to be replaced. If it fails, you'll end up with cracked heads. Not worth the risk and cost of fixing that failure.

The AOS can also be checked with a manometer. If it's out of spec, the AOS is cheap to replace. Again, only genuine Porsche.

Scott2.0

Wow, what a great document. Thank you! The shop did mention testing the flywheel's spring-back so it sounds like they me be aware of the tester mentioned.

When I called to ask about adding the AOS to the work order, they said it would add 2 hours to the job. There's no way, right? I pushed back and they are calling me back today after getting clarification.

THANK YOU!

Scott2.0

Here she is, by the way. New to me!

Charles Navarro

Two hours for the AOS in the car is reasonable. You also need to replace the AOS vent tube and the oil fill tube while you are in there. They are all plastic and we find them cracked which are leading to vacuum leaks and over-enrichment.

Scott2.0

Scott2.0

I just heard from the shop. My clutch slave cylinder is leaking so that's an add-on. The flywheel also failed the deflection test.

Here's a question. They're saying that doing the AOS now only saves about 15 minutes in labor and since it's not wet, they don't recommend touching it. Do you guys agree with that assessment?

Another thing that you can probably answer, Charles, I asked to keep the old IMSB and they told me that they have to send to you guys for the warranty to be valid. Is that the case?

Charles Navarro

About half the cars we see need slave cylinders. That's common.

That is indeed the case. The original bearing has to be sent in with the registration documents.

I don't go by visual inspection on the AOS. A manometer test is usually the way to go with that however I would defer to their judgement as they have your car and I'm more pro-active in my recommendations than most.

Scott2.0

Cool, thanks again!

Does it seem right that doing the AOS now versus on its own at a later time would only save 15 minutes in labor?

Macster

Never had a slave cylinder problem with my Boxster (or any car) but that doesn't mean your car's slave is not bad. If it is leaking it has to be replaced. Probably a sign the brake/clutch hydraulic fluid was not serviced regularly. Nothing you can do about it now other than to make a note to going forward to have this fluid service done on schedule, every 2 years.

Never did an AOS myself and I never watched any of the 3 my car required get replaced so I can't really dispute or confirm the AOS savings.

Even if the savings is only 15 minutes of labor, you have to consider that having it done now means you don't face having to bring the car again for this when the AOS does go bad, and it will. Every time the AOS failed on my car I faced a tow of anywhere from 10 miles to around 80 miles. The car is essentially undriveable with a failed AOS. While the engine will start and run the failed AOS can pass through oil from the crankcase and this can hydraulic lock the engine which can result in total engine failure. So if the AOS goes bad park the car and call for a tow.