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08' Cayenne Turbo, 102k AT black metallic, service records, 2 owner, comfort tan seating, wood interior package, two tone red-brown and tan interior, FVD Brombach tune and a bunch of bolt on mods, coated with fluid film black autumn 2022, my DD---
I've been noticing a rust stain while changing my ATF to Castrol Transmax with and FR3 friction reducer for various reasons (existing fluid was still good). The rust stain is definately not part of the metal rocker itself. I slightly pried on the plastic panel above the rocker and saw some kind of protruding thinner metal underneath and slightly above it, but not directly behind the panel. Is this a common issue in the rust belt area? What is the piece that has apparently not been rust proofed very well located there? Any suggestions for resolving it?
Take that cap off and see what's behind it. This is what mine looks like.
When you get to the point of rust stains down the rockers, this is likely behind that cap. The rot will soon creep up and start bubbling the paint above.
Pulling all the fender liners, checking the drains…and all the other hidden pockets behind those liners, is an annual task. Regardless of what climate you live in, sand, dirt, etc…packs in places.
Picture below is what the inside of the front left lower fender looks like, from an 09 GTS. A similar pocket to this, likely exists on all Cayennes.
Yep, cleaned up some rust in the same area on my 09 cayenne that lives in FL but grew up in Ohio. That area is susceptible because dirt traps moisture and it takes its toll. I also cleaned up some rust behind the trim on the driver side door that has a failed lower door seam. My method that has been very effective over past 20 years is to sand or grind the rust down and use por15. Top coat that with paint to protect the por15.
Take that cap off and see what's behind it. This is what mine looks like.
When you get to the point of rust stains down the rockers, this is likely behind that cap. The rot will soon creep up and start bubbling the paint above.
Wow, this is really helpful for this thread and shows just what can happen in this body location of front left fender. I haven't checked the workshop manual yet, as all I have is the 955 manual, but it looks like that plastic molding can be gently pry'ed off?
Pulling all the fender liners, checking the drains…and all the other hidden pockets behind those liners, is an annual task. Regardless of what climate you live in, sand, dirt, etc…packs in places.
Picture below is what the inside of the front left lower fender looks like, from an 09 GTS. A similar pocket to this, likely exists on all Cayennes.
I bet my inner lower fender looks like a combination of this picture and 19psi's photo, well not that bad since I have no rust on the outer portion. I am going to be switching this one to a Partial driver vehicle and then I can throw some effort at this issue and the checklist that was shared on this thread too, which is already 50% completed. After getting some advice here, I plan to clean up, rust convert and fluid film coat those vulnerable inner areas along with the door cavities as a more oil coating to help protect from corrosion.
The caps pop off easily and that area should be cleaned once a year. Fine dirt/sand collects back there and acts like a sponge by holding water. My Cayenne spent its first 5 years in New York (I assume they use salt) and the remainder in the Chicagoland area. Being minutes from the south shores of Lake Michigan, I'm in one of the worst rust belts in the country and my Cayenne is rust free. It's typically trapped water and dirt that rots out a Cayenne, and not so much salt.
Another problem area on the Cayenne is the passenger rear door. Open the door and look along the outer door skin seam where it curves (about midway and down). Porsche screwed up the sealing process in 2003 and left their mistake through the 957 run. Grind off any rough looking or bubbling paint, then coat with POR15 and spray it with a can of touch up paint. It's an area that's usually not noticed until the owner sees the rot coming through the outside of the door.
If you're unsure what that seam should look like, compare it to the driver side rear door.
Okay so, I cleaned out about 24 oz. of silt and dirt out of each side. The drivers side has about a 1/2" of rot around the hole. So I cleaned it really good, let it dry and sprayed the metal remaining with Amsoil HD metal protector spray for now. But this raises the question, is the 08' cayenne fenders the same throughout all the models? I'm considering also welding in a new bottom section in only to a perfectly good fender panel. Does anyone have one that's good laying around? I am assuming the bottom area aft the wheel well is the same between 955 and 957 models?
The caps pop off easily and that area should be cleaned once a year. Fine dirt/sand collects back there and acts like a sponge by holding water. My Cayenne spent its first 5 years in New York (I assume they use salt) and the remainder in the Chicagoland area. Being minutes from the south shores of Lake Michigan, I'm in one of the worst rust belts in the country and my Cayenne is rust free. It's typically trapped water and dirt that rots out a Cayenne, and not so much salt.
Another problem area on the Cayenne is the passenger rear door. Open the door and look along the outer door skin seam where it curves (about midway and down). Porsche screwed up the sealing process in 2003 and left their mistake through the 957 run. Grind off any rough looking or bubbling paint, then coat with POR15 and spray it with a can of touch up paint. It's an area that's usually not noticed until the owner sees the rot coming through the outside of the door.
If you're unsure what that seam should look like, compare it to the driver side rear door.
Do you have to remove the wheel arch liner to 'pop the cap off'? Any pics would be appreciated
06-23-2023, 05:47 PM
Rust stain showing up on FL Rocker 08' Turbo
After getting some advice here, I plan to clean up, rust convert and fluid film coat those vulnerable inner areas along with the door cavities as a more oil coating to help protect from corrosion.
