Metal Grinding Sound on Startup

I just went to take my car out to dinner, and I heard a metallic grinding for a second or two while I had the key turned, and the car didn’t start when I released it. I paused and turned the key with the door open to hear better what it was, and this time I heard the same sound but much quieter and it went away after 1 second and the car started. I turned it off and back on again a third time with no sounds. I just got back from work so everything was still warm. Car is a 2008 Cayman S with 96,000 km (60,000 miles)

I just took it out of my garage to check if it can still drive, which it can. Again no noises on startup.

If it were my ride, the first thing I would do is determine whether it runs correctly after ignition. If it runs great once it started, then say to yourself thank you God. As for where to go from there? I’d either get it to a shop of course, or I would pull that aluminum rear panel and observe, as I started the car. Maybe it’s just the starter, till then, I would park on inclines in case I needed to clutch start it assuming that it is a manual, but before that you have to determine whether the car runs correctly after ignition.

Maybe a weak or failing battery? How old is it?

Cheap cause to eliminate too, you can get a free load test at like Autozone

My guess would be the starter. Sounds to me like the solenoid is not fully engaging the starter gear into the flywheel.

I took it for a quick 5 min drive and everything sounded normal. No sounds out of the ordinary. I had a quick chat to a mechanic and they said something about the starter motor, and that it should still be fine to drive. They’re going to take a look at it after the weekend.

Off the cuff, @TheTheTheTheo - I'm guessing your starter needs attention. As the sound was right at the start, but not afterwards when you were driving around -- that's exactly when it sounds like when it was making the grinding sound. I'd definitely go grab another battery when you have a chance. Let us know how you get on with this. Cheers.

Or some missing teeth on the flywheel, (no whammy no whammy no whammy) spin.

Both are entirely possible - and unfortunately - the first failure mode can cause the 2nd failure mode (BTDT about 6 decades ago, when I was a poverty driver..) There is a sliding gear in the starter that engages the flywheel when you spin the starter motor using the key. Depending on the design - that gear is moved by a solenoid (that also makes the electrical connection) or by inertia - with a cleverly engineered curvy set of splines inside the gear and on the motor output shaft. Whatever way it's done - a weak battery can cause #1. If it grinds long enough it can knock or damage some of the teeth on the flywheel. That gets expensive because it leads to #2 - which requires engine out, probably a new clutch and flywheel and starter - I'd guess around $4k USD in total. So as suggested - perhaps a new battery for $200 USD installed (Firestone in the US carries Interstate, not sure about NZ prices..) might be a wise investment, and hope it doesn't happen again. It's probably more likely to happen with an infrequently used car since the grease on the splines for the gear can gum up and slow it extending into the flywheel. Your car with 96,000km in 16 years is a low-use car.

Costco has interstate as well

Are they in New Zealand? 😅

I would start with checking the starter, too!

Costco New Zealand in Westgate, Huge store 14,800 sq. meters

Assuming battery is good, I would say go ahead and get a starter as it will most likely progress eventually needing a new starter. Mine started this a couple of weeks ago and I put the new starter on today.

I had the same issue after starting the engine. Pulled the starter and lubed the bendix gear and it went away. A month or two later it came back. Not one hour ago I replaced the starter and it seems to be all better.

agree with possible starter issue. the 987's tend to need a replacement at about the 10-12 year cycle. mine occasionally refused to start/turnover when key turned and gradually got worse.

I had a very similar issue and it was a dying starter. You can get a great Bosch unit replacement on Amazon for a great price. Relatively easy swap out and problem solved right away. Cranks better than ever!

Here is the link to the starter I used BOSCH SR0808N Original Equipment New Starter - Compatible with Select Porsche 911 , Boxster , Carrera GT, Cayman https://a.co/d/6phtQOm

Once in a great while lubing it results in a long-term fix - but usually not. The cause of the binding is typically wear on the bushing at the flywheel end of the starter "nose" - the starter gear rides in that and there's quite a bit of force exerted on it. Considering the amount of work to R&R one - I'd opt for a Bosch rebuilt one every time. They're usually really new starters (sold as "rebuilt" so they aren't competing with their other vendors - like Porsche parts departments - in the US..)

This is the same starter I put on mine. That was the best price O was able to come up with and same experience with best starting I have had on this car that is pretty new to me, three months or so.

I got the battery tested and it was at 86% so likely not an issue relating to the battery. I was advised that I didn't have a very good battery which could have caused it. My car is used as a daily, so sees multiple startups per day, and the issue hasn't happened again. Hoping it was just a one off. My current plan for if it comes back is if it happens a second time, I'll replace the battery, and if it happens a third then I'll look into lubing/replacing the starter.

How was the battery tested? "86%" means nothing when it comes to the health of a battery, particularly an automotive starting battery. The only way to properly test it is with a load tester such as the one shown here. Everything starting/running starts (NPI) with the battery. Until that's sorted/known good, you could chase your tail.

It was tested using this exact battery tester. I believe it was 86% CCA?

The "percentage" showing on most battery "Testers" is just a guess. Unless.... You have a smart tester and all of the parameters of the battery under test have been input the tester AND there's a history/baseline for it to compare. Thus.... absent the above, IF that unit includes a load testing function, that is more important than any percentage reading. I'm not saying you are wrong, just pointing out that based on the data you have given us, we cannot know a proper load test has been done on the battery. Once you have a known good battery, the next path is (literally) the current to and from the battery. Check the cables and the ground path return. All of the above could cause not enough current at the starter. That said, it still could be mechanical as in the starter not fulling engaging the flywheel for various reasons such as not operating properly due to age/dirty/lack of lube or damage such as gear teeth missing on the starter or flywheel. You/we need more data.