996 spark plugs - interval not followed in car I'm buying

Hi I'm in the process of arranging purchase of a 996 C4S privately. I'm having a PPI done from the same place the seller had the IMS bearing upgraded. I've just noticed that despite all the works the seller has done, and the low mileage (sub 50k) it appears they didn't change the plugs since 2019. I assume the PPI would pick up on an seized plugs? Or should I ask that the seller change them immediately at their own cost? Or is this a "walk away" situation? I really like the car and planned to use a main Porsche dealer for all future servicing given the low mileage and which will help with future value. Or am I over worrying?

I wouldn’t say it’s a walk away situation if everything else has been maintained but if it’s been serviced properly and by that at its last major service then the plugs should have been done as a matter of course. What sort of paperwork and invoices does the car come with as that should be a good indicator of money spent on doing preventative maintenance

Definitely not a deal breaker for me either... don't overthink things.

Old plugs will probably eventually cause the engine to misfire but I'm not sure how they would really do any harm.

Spark plug electrodes gradually and slowly wear down over thousands of miles, this can result in an excessive gap for the spark to jump and in the olden days plug gaps were adjusted to ensure maintenance of optimal gap for best combustion. Modern hot running engines can burn away electrodes quicker- sometimes to the point of bits of electrode falling away and potentially colliding with valves, bit this is over tens of thousands of miles. The insulation ceramics can break down and crack causing misfire but this is unlikely to cause lasting harm. So plugs left in the engine that haven’t covered Star Trek miles but still produce a good spark, indicated by smooth tick over and clean revving with no misfiring/faultering would cause me no concern whatsoever. Many owners may look at the plugs periodically and check condition and the ‘plug gap’ and continue using them if good no matter how old they are. With a pre dfi engine older spark plugs would be the least of my worries!!

If you're having a borescope done as part of the ppi then they remove the plugs to do that, so I'd ask them to look at the condition of the ones that were in. So what problems can not changing the plugs cause. The first is that they're physically worn out, in extremes this will cause misfires which can in theory damage the engine and cats, however the engine management will log the misfires and put the engine management light on for emission reasons long before any damage occurs. The next is they can get excessive carbon deposits which can then damage the threads in the head as they are removed. The servicing recommendations from Porsche are very conservative, most plugs will take 20-40 thousand miles to wear out. I change mine in my turbo every 4 years after 4-6 thousand miles and there's no visible wear, and they unscrew by hand! Also if the old ones are being removed for the ppi I'd suggest talking to the current owner and asking for new to be put back in, also new coils if any have cracks which is very common. This would benefit both of you!

Overthinking it, equally having a 996 C4S maintained at a main dealer seems equally mad. Find a good Indy and get better service. You are buying the car in front of you. A PPI may make you slightly better informed of its condition (or it may not as PPI aren’t a guarantee) and you can make an offer accordingly. But if a buyer demanded I do something at my own cost they would be shown the door pretty quickly. If you want that sort of engagement, buy from a trader

Thanks for the replies. My only concern was that they could be seized and damage the engine on removal, but again I assume the PPI would cover that if it was an issue. The records I was sent show services in 2024 & 2025 so I've asked them to clarify, maybe the plugs were changed.

The engine in the c4s is not known for plugs seizing, the later dfi engines however is a different story.

They will only be siezed if overtorqued when they were installed, taper seat plugs especially. Just because they aren't in the service does not mean they haven't been done, you could take the thought exercise further and ask if any coil packs were showing evidence of replacement or cracking. People put far too much faith in service records they prove nothing when it comes to the quality of maintenance even at Porsche dealers. I'd put the standard of my cars up against any dealer or independent maintained cars. On the PPI front if it is a thorough one then if you don't go in eyes open it will for sure put you off, you will see all the defects that were found though your mind is probably expecting a defect free report - that ain't happening - I could find defects on a new car in the showroom. You have got to expect some work / TLC is needed - you aren't buying a new car. Could the plugs be siezed yes, could they be cross threaded given where they are very much yes, no PPI is going to identify this. Bolts and such can and will be siezed in suspension components but that is just a fact of life and can happen to any car. I concur with the overthinking it. I guess it depends on the extents of your resources and how much you're prepared to put into it. For me nothing is a walk away but price must reflect.

Well given the mileage the price is on the higher side. In fact I could get a 997.1 C4S for the same price, but I dislike both the front and rear of the 997.1, fugly as hell. The 996 wide body looks a lot better, and I even like the headlights! I'm looking for something as retro as possible without the stupidity of older Porsches and their absurd prices.

I’ve just done my plugs that were last done in 2019, I bought the car in 2020. Plugs were still pretty much as new having only covered 10k miles in last 7 years. Really need to balance miles vs age on these types of things, manufacturer intervals are meaningless on low use cars….. simply throwing money away on some age replacement components.

There's a bit more to this than throwing money away - for me at least - not sure about others. When I take on a new car I want it in a place that I know for sure, I don't trust history, I don't trust work that I didn't do - because I was in the trade and know what kind of **** goes on. Of course the OP and others may have different perspectives but that's fine - your car, your rules, your problems including the self inflicted ones.

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To me the 996 narrow body looks best because it doesn't have stupid looking massive archs And why do people think a 911 - or any sports car in general - needs 4wd To me the 996 is retro because it has small subtle arches and less power, less tyre, less brake disc, less size, less weight, less less less of everything

If you'd driven one you would know