You really do need to get to 2009 to avoid serious issues with porsche since the 996. Even then, still need a bore scope just in case.

Parts and labour are absolutely hideously expensive, even at an indy.

I had two O2 sensors, oil change, MAF sensor done, was over $2K.

Dino GT wrote

Bore-scoring has a lot to do with how you treat your car.....

Never let your Porsche engine idle to warm it up. Start out slowly and keep engine rpm below 3000 rpm until the engine is fully warm.

This does seem to be generally case with regards to bore scoring. Though very rare (so I read), bore scoring can even happen in the 9A1 motor found in the 987.2/997.2 cars like mine. The experts and Porsche techs say that on a stone cold motor, start it and let the "choke" idle come down to normal rpms (~30 seconds) and then drive like normal, keeping the rpms below 4000rpm. Then after 10-15 minutes, depending on ambient temp, the oil should be fully warmed and you can let it rip. Due to the lack cylinder liner inserts in many Porsche motors, if you beat on a cold motor, you run the risk of bore score because the piston/ring to cylinder bore are too tight when cold. You need to get some heat into the motor and the oil to temp.

What does impress me about the 9A1 motor in my Cayman is that it's a forged crank, forged pistons, and closed deck block. That's nuts for a street motor and way over-built for a 2.9 liter.

Dino GT wrote

I don't find BMW's that much different than Porsche's when it comes to reliability. They both have their known issues when it comes to parts failing and/or wearing out over time.
I find a lack of general maintenance by some people causes a lot of unnecessary problems/issues over time.

BMW's are known for having isues with the automatic headlights, battery discharging, blower motor, power steering pump, fuel pump, water pump, coolant system, leaking oil filter housing gasket, leaking valve cover gasket, worn suspension, belt tensioner, window regulators, vanos solenoids, etc, etc.

With Porsche's you have the air oil separator, rear main seal, ignition switch, battery issues, worn suspension, shifter cables, cracked coolant reservoir, water pump, window regulators, etc, etc.

The M97.21 and M97.22 engines 3.4 L in the 06-08 Cayman S have the much larger non-serviceable IMS bearing, it requires engine disassembly to replace it, and IMS bearing failure on a M97 is very rare, I'd be more concerned with bore-scoring than the IMSB on a M97 engine.

Bore-scoring has a lot to do with how you treat your car.
Buy top tier or ethanol free premium fuel. Instead of changing the oil every 12k miles or once a year, change it every 5k miles or every 6 months.
Never let your Porsche engine idle to warm it up. Start out slowly and keep engine rpm below 3000 rpm until the engine is fully warm.

What is the thinking behind “never let your Porsche idle to warm it up”?

Dino GT wrote

By letting the engine idle to warm it up the rich mixture during cold start can wash down cylinder bores and that can cause bore-scoring. That's why It's very important to start driving immediately but keep engine rpm low until the engine warms up.

I'd say this goes for ANY vehicle. Even though bore scoring isn't an issue in most engines, idling to warm up is just terrible for catalytic converters and the oil because the engine stays in a prolonged rich running condition which can foul the cats over time and put excess fuel into the oil. Some owners also incorrectly assume that because the engine is warmed via prolonged idling that they can speed off. That couldn't be farther from the truth as the transmission fluids are still stone cold. Driving is what heats up the trans and diff fluids, dummy!

Porsche's propensity for keeping everything as light as possible is in itself a reason why wear and tear should be expected more frequently on these than others with a solid build.
Great when they're running perfect but sadly the worst marque for reliability over the pond here.

M5Rick wrote

Porsche's propensity for keeping everything as light as possible is in itself a reason why wear and tear should be expected more frequently on these than others with a solid build.
Great when they're running perfect but sadly the worst marque for reliability over the pond here.

Um, yeah, I don't think this is backed up by any facts or data. While I think Porsche's reliability is not as sterling as their reputation, I have a hard time with this. Not a solid build? Worst over the pond here? Didn't realize they built them like shit for the UK on purpose.

chris719 wrote

Um, yeah, I don't think this is backed up by any facts or data. While I think Porsche's reliability is not as sterling as their reputation, I have a hard time with this. Not a solid build? Worst over the pond here? Didn't realize they built them like shit for the UK on purpose.

Here you go.
https://www.thecarexpert.co.uk/porsche-named-least-reliable-car-brand/

Here's JD Power's Long Term Dependability study data for 2022 which shows Porsche and BMW are well above the industry average in terms of reliability.

https://www.jdpower.com/business/press-releases/2022-us-vehicle-dependability-study

With that said, when we're talking about 10 year old cars, degraded plastics, rubber, hoses, bushings, suspension components, etc. will require replacement. Nothing lasts forever.

Dino GT wrote

By letting the engine idle to warm it up the rich mixture during cold start can wash down cylinder bores and that can cause bore-scoring. That's why It's very important to start driving immediately but keep engine rpm low until the engine warms up.

This is mostly a holdover from carbs and early EFI systems. Modern port and direct injection don't run excessively rich, even on startup and idle, and do a good job of atomizing the fuel. Oil squirters are still working too. I know people that have like 100-200k miles on cars with remote start that they idle for 10+ min every day in the winter. I am not recommending you cold idle for long periods, but it isn't high risk.

The bore scoring is just a design defect. Same thing with S65 rod bearings. People love to blame the user. Let's be honest, Porsche has a really bad history with cylinder linings / skirt coatings. People remote start and idle BMWs all the time and there's no bore scoring.

XutvJet wrote

Though very rare (so I read), bore scoring can even happen in the 9A1 motor found in the 987.2/997.2 cars like mine.

It does happen though. When at my indy there was a 991 'S' with 45,000 miles, he turned it over and SLAP SLAP SLAP SLAP SLAP SLAP ..... bore scoring cylinders 4 and 6 I think. $30K, thanks for coming.

That's why I had mine scoped.

Dino GT wrote

Yes, bore-scoring is a design defect with Porsche M96 & M97 engines, not with BMW engines, at least not that I`m aware of. It`s like you said "Porsche has a really bad history with cylinder linings/skirt coatings" but as far as I know it`s only with the M96 & M97 engines. There`s nothing you can do about it if you own a Porsche with one of those engines except to try to prevent bore-scoring.
I even use a bottle of Liqui Moly 2030 Pro-Line fuel system cleaner every 3000km.

I thought 9A1 also can suffer from it, though not as frequently?

chris719 wrote

I thought 9A1 also can suffer from it, though not as frequently?

100%.

chris719 wrote

This is mostly a holdover from carbs and early EFI systems. Modern port and direct injection don't run excessively rich, even on startup and idle, and do a good job of atomizing the fuel. Oil squirters are still working too. I know people that have like 100-200k miles on cars with remote start that they idle for 10+ min every day in the winter. I am not recommending you cold idle for long periods, but it isn't high risk.

The bore scoring is just a design defect. Same thing with S65 rod bearings. People love to blame the user. Let's be honest, Porsche has a really bad history with cylinder linings / skirt coatings. People remote start and idle BMWs all the time and there's no bore scoring.

"Running rich" doesn't make sense.

Agree scoring is a defect, caused by cost-reducing the cylinder coating. Aluminum cylinders with hard coating is a great lab research project with PhDs building the engines but not so great in mass production. MB has it also, read about the M278 and M157 V8s.

Dino GT wrote

Yes, but the 9A1 engine is far superior to the M9X engines.
Most of the scoring occurs when the engines are still cold.

That does seem to be the case. It seems that just because you got the motor scoped and it's all clear doesn't mean the issue can happen a few thousand miles later.

I do read reports of scoring being more common in cars driven in colder climates and obviously in cars driven hard when not warmed up. However, if you go down the bore scoring rabbit hole, there are plenty of cases of well-maintained motors in warm climates suffering from it.

Late model BMW motors like the B58 and related motors have a plasma coatings instead of iron liners. There are instances of these coatings failing in the B58s, the culprit being leaking DFI injectors. I do have to wonder if the DFI 9A1 motors are getting bore scoring from a similar leaky fuel injector issue.

Shame on Porsche for not pushing the easy button and sticking to iron cylinder liners. The fractional gain in mpg of using these cylinder liner coatings seems largely offset by a potential catastrophic failure of the short block at great expense to the owner.

Alfisti wrote

It does happen though. When at my indy there was a 991 'S' with 45,000 miles, he turned it over and SLAP SLAP SLAP SLAP SLAP SLAP ..... bore scoring cylinders 4 and 6 I think. $30K, thanks for coming.

That's why I had mine scoped.

These repair costs are just bonkers. There's nothing inherently special about the way these H6 Porsche motors come apart and go back together. If anything, a Subaru boxer motor is more difficult fully disassemble/assemble. Same for the parts costs. Yeah, they're high-revving 6 cylinder motors that can make good power, but Honda and Nissan have managed to make high revving 6 cylinders for the masses too and with similar power per cubic inch.

XutvJet wrote

Shame on Porsche for not pushing the easy button and sticking to iron cylinder liners. The fractional gain in mpg of using these cylinder liner coatings seems largely offset by a potential catastrophic failure of the short block at great expense to the owner.

Porsche is just ahead of the curve. They seem to try stuff out before they become mainstream. I don't think it's for fuel economy only; it's for cost / ease of mfg and the arc sprayed coatings are actually superior.

5/11/2023 Update

Over the past couple of months I've done a number of repairs, preventative maintenance, and mods as noted below. I'm very happy with how the car is progressing.

- New brake light switch
- New clutch pedal switches
- Replaced the 13 y/o air/oil separator (AOS). I disassembled the AOS and the rubber diaphragm still looked good. The car has never smoked on start up or otherwise
- Replaced the vent line from the AOS to the throttle body assembly. The vent line had some oil residue on it which after further inspection was caused by a nearly impossible to see crack in the corrugated plastic.
- Installed new coil packs. The original coil packs did not show any signs of cracking.
- Installed satin Soul Performance exhaust tips and x-pipe
- Installed Cayman R "Porsche" side decals
- Rattle can painted the black plastic front spoilers Carrara white and clear coated with 2K clear.
- Plasti-Dip the headlight washer nozzles black (originally chrome)
- Cayman R-style headlight surrounds
- Smoked translucent vinyl on the fog lights and running lamps
- 8mm ECS spacers in the front and 12mm spacers in the rear
- Black painted OEM muffler cans (they bronzed and had some surface rust)
- 40% window tint

Next up is the Function First shift kit and a new gas cap as the car has thrown the P0441 code twice now over the past 6 months and the gas cap rubber seal isn't in good shape. The Cayman R springs and shocks will be done next spring.

XutvJet wrote

5/11/2023 Update

Over the past couple of months I've done a number of repairs, preventative maintenance, and mods as noted below. I'm very happy with how the car is progressing.

- New brake light switch
- New clutch pedal switches
- Replaced the 13 y/o air/oil separator (AOS). I disassembled the AOS and the rubber diaphragm still looked good. The car has never smoked on start up or otherwise
- Replaced the vent line from the AOS to the throttle body assembly. The vent line had some oil residue on it which after further inspection was caused by a nearly impossible to see crack in the corrugated plastic.
- Installed new coil packs. The original coil packs did not show any signs of cracking.
- Installed satin Soul Performance exhaust tips and x-pipe
- Installed Cayman R "Porsche" side decals
- Rattle can painted the black plastic front spoilers Carrara white and clear coated with 2K clear.
- Plasti-Dip the headlight washer nozzles black (originally chrome)
- Cayman R-style headlight surrounds
- Smoked translucent vinyl on the fog lights and running lamps
- 8mm ECS spacers in the front and 12mm spacers in the rear
- Black painted OEM muffler cans (they bronzed and had some surface rust)
- 40% window tint

Next up is the Function First shift kit and a new gas cap as the car has thrown the P0441 code twice now over the past 6 months and the gas cap rubber seal isn't in good shape. The Cayman R springs and shocks will be done next spring.

Looks great!

Well done on the AOS and coils. I change coils at 100k miles regardless of their condition. They are wear items.

The side decals look good. I don’t like them on all P-cars, but they look good on your Cayman.

There's a black '13 718 a few doors away from a family members house and it looks great although always looking filthy lol.
If I'm not mistaken the 718 designation is the same for both the later Boxters and Caymans with the earlier Boxters at 986.

Man that's a LOT of work, wow. You'd be broke if you were not doing it yourself. Looking good though, and we both have the same wheels.

Alfisti wrote

Man that's a LOT of work, wow. You'd be broke if you were not doing it yourself. Looking good though, and we both have the same wheels.

Yeah, it's been pricey for sure, but I knew I'd have to do a lot of this work when I bought a 10-13 y/o Cayman. Luckily the car is surprisingly easy to work on. I've done all the work myself but the clutch/flywheel. I would have done that myself too if I had a lift as yanking the trans is EASY on these cars.

-Sachs clutch, OEM flywheel, and new muffler straps (originals were rusted) installed for $2900
- OEM engine mount, engine mount "bumpers", and transmissions mounts $650 - 4 hours
- OEM updated shifter cables and associated updated mounting hardware $600 - 4 hours
- Clutch switches (2) $60 - 10 minutes
- Brake switch $30 - 1 minute
- AOS $120 - 1 hour
- Vent line from AOS to the throttle body assembly $90 - 5 minutes
- OE coil packs $250 - 1 hour
- New air filter $30 - 10 minutes
- OEM coolant reservoir caps (2) and oil cap $80 - 5 minutes
- OEM gas cap (leaking seal causing gas tank vent code) $20 - 1 minute

Yep, over $4,800 in parts and labor. Luckily, Porsche Colorado Springs gave me a check for $3000 so out of pocket, I'm around $1,800. All the suspension bushings look fine, but I still need to address from suspension bumps stops. I'll do that when I install the Cayman R suspension next year. For now, I just cut off the degraded upper portion of the bump stop and installed a piece of left over bump stop from the M235. 5 minute temporary fix