Older 997 rust issues - fixed in the 991? - Page 1 - 911/Carrera GT - PistonHeads UK

It seems that the 997 is quite prone to rust - is that the case? Did Porsche make improvements to materials used in the 991 to resolve this?

Fittings rusting - particularly exhaust clamps, tandem pumps (on the 997.1), wheel nuts etc - are an issue on most modern Porsches. I recently removed all the under trays, sill covers and wheel arch protectors to check our16 year old 997 (driven year round on muddy and salted lanes) with the intention of waxing it. Other than some mud and debris caught in the real wheel arches, some rusty screws and 2 flaky powder coated cross bars it was spotless. Gave it a coat of Bilt Hamber while I was in there, but very reassured. Just don't ask me about our 1989 3.2. It was already rusting at the same age, and needed new kidney bowls, sills and inner wings by 25 years. And our 993 had issues below the screen, and underneath at the back too. I wouldn't worry about rust on later Porsches, but it pays to watch traps like the front of the rear wheel arches. And you can get some superficial rusting on stone chipped areas behind both sets of wheels. That said, any car can rust and if your scour the forums you will find 996s and 997s that look like they have lived in the sea, but it's unusual.

Tandem pumps an issue on the 997.2 also. But at £140 it’s not exactly a showstopper. Exhaust clamps, nut’s bolts, studs made from specially conditioned steel (that special conditioning involves using the cheapest, nastiest steel made from scrap Lancias and early 911’s …)

Some seem to have rust issues. Mine (2006) has had rear arches rusting, cut out redone and now blistering again 3 years later, side sill rust, similar treatment and recurrence. It is an issue, and I’m told by local specialist a real problem if you have it, creeps into rear arch seams etc etc. Last fix was £12k with respray. Bit difficult to know what to do from here. Reluctant to chuck more money at it, but rest of car is spot on, although on average over 18 years ownership it’s cost about £6k per year to maintain/run. Real money pit territory now I think.

My experience is with 987 Cayman S and 991.1 C4 Cayman S very similar chassis to 997 apart from the obvious differences related to engine position. Main rust areas for me were around the jacking points spreading to the sills. 991.1 C4 was exactly the same. I put this down to the way the body was assembled because the chassis jacking points were used to hold the body firmly as it went through the assembly and protection process. The jacking points did not receive the same corrosion protection as the rest of the body is my theory. Videos of the assembly process shows this. The 991.1 C4 has a very, very different chassis from the C2 but the basic assembly techniques are the same. It's worth noting that the 991 sills were quite sophisticated In that they had what appeared to be active ventilation in the sill cavity. If you look closely the sills have two venting valves on the underside and they have a rubber louvered vent cap at the ends. Changes in pressure will open and close these vents. Note !! you should remove all arch liners annually as, in my case, the end cap vents were blocked with debris. 987 did not have any of this sophistication. I would also, as a one off, remove all undertrays and examine all sealed joints for poor sealing, I found a few on my 991 this resulted in small pockets of rust forming under the sealer at joints. Sills were riveted and bonded to aluminum floor I would expect the sills to last a long time with attention to what I have mentioned. I sprayed additional corrosion inhibitor in the sills and inside the wheel arches just to be sure as well as sealing any suspect joints. I don't have the car now so someone will be benefiting from my OCD. Edited by DuckDuck on Saturday 10th August 16:47 Edited by DuckDuck on Saturday 10th August 16:49