Preventive Maintenance- Rusty Exhaust Headers

I've been working through a list of bits that were flagged on the last service and so far addressed a rubbing clutch to coolant hose, replaced rusty brake lines (surprisingly easy) and replaced front drop links (one easy and one very stuck). I'm also considering replacing the IMS (professionally inspected a few years ago) and the OAS if I'm feeling brave, and the hard lines on the steering rack which I also noticed have a good amount of surface corrosion. Just to note that it's a C2 on 80k miles and it has no concerning symptoms (no smoke, no noise on startup or whilst running) and it has regular professional servicing and I have addressed issues myself where needed. So this is purely about preventative maintenance. It's the first time I've put the rear high enough to get under it, so had a good look around. The exhaust headers look like puff pastry where they join the block and the bolts are in poor condition. There is no physical or audible sign of an exhaust leak however and the rest of the exhaust system is ok. So the question is, given the the chance of shearing bolts. Should I tool up and go for it or leave it alone?

The same question is often asked on here. If they're as you describe, which is normal for the UK, there's a very good chance around half of them will snap but could be all or somewhere in between. Either way once they've snapped you have to do something about it, which means either paying someone to do it (you'd then need to get your car to them) or drilling them yourself with a jig and high quality cobalt drill bits. You're other option is to leave alone until you're forced to do something, that could be very soon or in 50k miles , that's what I'd do in your situation. First thing I did when I bought my low mileage Turbo was to get it on the lift and remove all the header bolts and coat them in moly anti sieze and put them back in. However they still had the factory coating on them and came out easily.

Don't replace the IMS. If anything, just remove the seal on the bearing. This then allows fresh engine oil to lubricate it.

To do the bolts, you'll need to buy/rent/borrow a Stormski jig:

Personally, I'd leave well alone until you're forced to. The chances of something going wrong is high!

If you dont need to remove the exhaust headers then dont... Unless you really want to... If they are not leaking then they will be fine for a good while yet. As already indicated, you will have a pig of a job on your hands. Not impossible, but a pig...

I'm now in the same boat as the original poster. After 20+ years my PSE boxes are showing distress, and the MOT tester (who has known the car for at least 8 years) collared me after the latest MOT to tell me that three bolt heads have snapped off the header/cylinder head connection - but no leaks. After canvassing opinions on replacement systems (I've owned 3 996s since 2002 and followed several forums) I'm leaning towards renewing the factory made PSE. I like the sound and several posters have commented adversely on other makes (no names, no pack-drill!) and mentioned long term failures and fractures of non Porsche systems. Rather than risk a breakdown....I foresee grazed knuckles and copious bad language.

'If not blown then leave alone'

I (well, my local mechanic) did mine within the first year of ownership as I knew it's only get worse and come back to bite me. I've since gone through 2 sets of manifolds and also had to have them removed for other jobs, like fitting a new variocam solenoid. I can now remove and refit in under an hour, so as far as I was concerned, best thing I did. One of mine was very slightly weepeing but no evidence until I removed it.

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Just completed this very job using a Stomski jig, because the manifold, studs/nuts and silencers were very rusted and I also wanted a better sounding exhaust system. So I decided to go for it and bought secondhand Stomski jig, DesignTek manifolds and mild sports silencers. I video the whole process and also took the opportunity to change the waterpump, thermostat, remove the catalytic converters and changed rusty lambda sensors. There are 6 videos In summary, its a tough difficult job and pretty stressful (i had to replace a stripped manifold thread). You need plenty of time and patience, but I dread to think what I would have been charged by a Porsche specialist, so in my case, I think it was worth it. However, if your exhaust is OK and you are happy with the sound etc. I would think twice about doing the job. If you decide to go ahead, I can sell you the Stomski kit.

I think based on the replies I'll probably leave the exhaust alone for now. It was just the appearance of it and wanting to keep the car as well maintained as possible. But I can picture the feeling of regret as the first bolt head shears off and I'll wonder why I didn't just leave it alone! Those jigs and ridiculously expensive! I think I'll tackle the power steering pipes next, around £50 from design911. The IMS perhaps next, from the paperwork and speaking to the specialist there was a ton of work done at the same time including clutch and RMS and it was deemed ok to leave the IMS. I assume the seal was not removed.

Is your car a gen 1 or gen 2? If gen 1 then no need to do anything with the IMS except remove the dust shield if not already removed. If gen 2 and the inspection was recent then I would prob leave well alone until you actually have to have the gear box off. At that time you can inspect the bearing and decide then.

^^^THIS^^^

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It's a gen 2 (2003). The clutch was done by previous owner and IMS check around 6 years/ 14k ago. So I'm thinking it would be worth checking IMS again soon. I've had 4 years of relatively routine maintenance- major/ minor service and yearly checks. In that time I've personally also replaced a leaking high pressure power steering hose, water pump and thermostat, pads and discs and the battery (twice). My understanding is the manual gearbox removal on a C2 is not too difficult, even for a driveway mechanic?

I went down a similar rabbit hole recently with my last 996. Gearbox out and ended up replacing the Porsche IMS for an EPS one. I did this in my garage on axel stands - all be in tall ones. So it is doable at home. If your keen to get in there for a look then we will all enjoy being with you on the journey. If you are in any doubt then you could get an oil sample analysis done by Millers - it would at least tell you if anything was starting to break up...