Porsche Enthusiasts Club Forum

Hi All,
Attached is a photo of rust that I have in the inner sill, taken through the hole in the door pillar on the drivers side.
From the outside there is no sign at all - all the external panels around this are still very solid and original looking, no sign of previous repairs. I'm guessing if I do nothing it may last a few years (or less) before it shows on the outside.
Ideally it would be good to be able to treat it with a rust converter, then a wax type treatment - but it is not accessible for the former. I am therefore thinking that I should just treat it by spraying in something like Dinitrol ML or Dynax S50, and that will make it last a lot longer, but presumably not cure it.
If I take this approach, presumably sometime in the future I'm going to have a big, expensive sill replacement job. Is there, and should I be considering some other approach, e.g. cut it open such that I have access to treat the rust, then weld it closed again?
Basically, does it make more sense to try and do something significant now rather than wait for the inevitable?
Thanks for any advice you can give.
Alistair.

Hi Alistair

It depends really how much time/money you want to invest. What you can see may just be the tip of the iceberg. If you google some 944 sill repairs you will see some pretty nasty corrosion. I've got some pics of my sills off, which on one side didn't look too bad from the outside, but once the old sill was cut off and the wing removed, extended into the floor pan and bottom of the A post. Most things are repairable, just takes time/money. It really depends how attached you are to the car and Its not really a decision you make with your head as the costs will quickly exceed the value of the car.

best of luck with whatever you decide to do

Brian

its a cut out and repair job, if you can see rust there it will be elsewhere, I have done several sets of sill now and when opened up its always rusty in more areas of the sill and inner sill.

Thanks for the replies guys.
Think I'm going to treat it for now, then monitor closely, review again in the summer.

best rust inhibitor is oil ..you don't see a spec of rust under a car that has an oil leak from the crank or diff .I used a mix of oil and grease with a little diesel to thin and it kept the rust at bay for several years until I could get around to dealing with my rusty sills .Oil creeps into every area whereas a lot of proprietary rust treatments stay where they are sprayed .

You may find this of interest if you are considering doing the work yourself on a budget . I repaired mine for £20 each

https://youtu.be/rdAb8p-cNvs

Very much this.
And I'm new here so don't want to turn up telling people what is what or anything. But the pics from the opening post are to me at least not an issue worth getting concerned over. I very much doubt any 944 sills look any better than that. To me that looks like the early onset of surface rust which if coated liberally in waxoyl, oil, dinitrol, anything sticky and oily really, will hold that back for many years to come. You could spend 30 or 40 quid on it, or you could spend a couple of grand. But you probably won't enjoy the car any more doing so.

Fluid Film is another good protection against rust. It is available in a spray can also.

Does this also stop an already rusted patch(maybe in a sill where difficult to remove) from getting worse?

https://www.rust.co.uk/product/fluid-fi ... roofing-71
I've used some of their stuff including Fe123 difficulty is, getting at that area. Any rust retardant is not a long term fix. Best stuff I've used is POR15. Did the battery tray 5 yrs ago and it's still good.

would second the last few posts,doesn't look that bad,just get as much rust inhibitor in there as you can and keep an eye on it.
The screwdriver test is the one I use ie a sharp jab with a screwdriver ,if it bounces off leave it alone,if it penetrates and goes through you know you have a problem.
I did a lot of work on mine around the bottom of the A post and the adjoining area of floor where it curves up into the foot well and it was a real pain in the ....
Cheap because I did it myself but hours and hours of cutting out rust/ bodged repairs and prepping so my advice : don't touch until you have to .