Cavity waxing a Boxster

[pothole]

Saw some hideous pictures of a 944 with rotten sills, made me wonder about Boxes as mine is getting on ('97 build).

Does the 986 have a sill (think you US types call sills rocker panels) cavity that can be treated / filled with rust prevention gunk?

[southernstar]

Pothole, I wouldn't apply aftermarket rustproofing to the Boxster. The entire shell is galvanized, including the seams, and as I recall the original factory warranty was voided by the application of rustproofing. The 'goop' can start to peel and can actually hold water/moisture againt the metal.

Brad

[pothole]

Here's a galvinised 944:



986s are going to rust, it's just a matter of when.

The factory warranty on my '97 is surely long, long gone.

The use of stuff like dynax s50 is surely very common on older cars and serious resto projects, surely? I assumed the reason why it's not talked about much round here is because we're only now approaching a point where early 986s are old enough to merit some thought on rust proofing.

Do you disagree?

[fatmike]

I'd rather just worry about my IMS thank you...I don't need anything else catastrophic to worry about...



/

[pothole]

Was really just thinking about buying a couple of cans of dynax and filling the sills. And then not worrying about it!

[AndyA6]

Hmmm, never heard or seen a rusted Boxster come to think about it.

Anybody seen anything?

[Flavor 987S]

This is why I don't drive my car in the rain or winter time.

[jaykay]

A while ago I did two track days in the rain. Of course the window was open and a lot water was collecting on top of the door and probably draining into the door

I sprayed rust proofing liquid down in there and let it drain out. There also plugs in the bottom of the door which pulled out to let everything come out

Track day rain maybe an unexpected potential corrosion mechanism for those who drive in the summer only.

You may want to consider running some racers tape over the window opening before each session to avoid this

I don't recall spotting any rocker ports

[southernstar]

Pothole, I have little doubt that dynax is a decent product - if you are covering corrosion free surfaces. In fact, Porsche, BMW and VW all coat their underbodies and susceptible cavites with a wax that does not interfere with the galvanizing and which I suspect is a similar product. The problem with applying it now is that, if there is already some internal corrosion, the wax will only seal it in temporarily. The additional problem is that when you drill holes in order to spray in the dynax, you will remove the galvanizing from the hole and, as these holes are often on the top of the panel, it is very difficult to ensure a good coating on the inside. Finally, the plastic plugs for the holes also tend to hold moisture in against the metal where they are installed.

Simply because a Porsche 944 has badly rusted rocker panels/door sills, does not mean that the the Boxster will suffer the same fate. Yes, both cars are galvanized; however, the 944 must have had inadequate drainage at the bottom of the sills; indeed, it is even possible that an aftermarket coating filled the holes and allowed water to accumulate. There could also have been body damage there which was poorly repaired at some point (and if you have a damaged panel, the inside does need to be recoated). Simply put, we do not know thehistory of the car.

In any event, I live in an area where the roads are salted heavily over the winter and I have yet to see a rusted Boxster. Trust me, salt is much worse than water alone in terms of causing corrosion (and for that reason, I do not drive my car in the winter). Nevertheless, even Boxsters that have been driven over the winter here are rust free.

While Porsche's were notoriously susceptible to rust through the mid-1970's, they are now one of the best marques in that regard. I fear that by drilling holes and spraying in dynax that you may be making things worse, rather than better.

Brad

[pothole]

Thanks Brad, take you points.

One thing I'll say is that 944s with really rotten sills are common here in the UK. I doubt that's because they've all been mucked about with. They just rust. All steel body cars rust.

[southernstar]

No argument, Pothole - all steel cars can rust. In Canada, many people drill holes in the body cavities of older cars and have oil sprayed throughtout annually before the winter. As with traditional rustproofing, the holes are then plugges with removable plastic plugs. It leaves one heck of a mess beneath the car for awhile until the dripping stops, but at least oil will put a coating over existing rust which will dramatically slow the process. It is somewhat akin to coating iron/steel tools with oil prior to storage.

Care must be taken, however, as I am unsure how the oil would react with the existing wax/based coatings on the Porsche!

Brad

[Mark_T]

I'm just surprised that a title like "cavity waxing" hasn't drawn in JD like a wasp to a spilled slurpee.