I have read a lot of questions/threads around the internet concerning rusting strut towers on 96-00 minivans. As the owner of a 1998 Caravan that has its strut towers attacked by the tinworm, I have some good experience and done a lot of research on it.
Unlike most cars, where the strut towers are in the middle of the fender area, the Caravan has it strut towers affixed in the far corner between the fender and firewall. Thus, if water leaks in from the hood, it puddles in the corner and eats away at the tower. Now, (this is an original theory based on my own observations), it seems that this mainly effects Caravans that have been previously in front end collisions; this tweaks the unibody and prevents the hood from sitting/sealing right, allowing the water in. I have seen Caravans with clean factory strut towers, and these have the hood sealed right around the cowl. Mine has been in two front end accidents (both before I got it), and I think that has contributed to my strut towers rusting, as my hood sits cockeyed and even sticks up in the corner by the cowl on the driver's side about 1/4".
Now, these towers have a weird pattern of rusting. The driver's side tower always take the brunt of the blow, with the passenger usually receiving minimal rust. When the tower starts losing its structural integrity, it will start to bulge up at an angle right by the fender. That is because if and when the inevitable happens, it always is around the outer perimeter of the tower; the main mounts hold up. When it does break, the outside crescent of the strut on the right side (POV of standing in front of the car, looking under the hood) breaks through at an angle. Thus, it is important to inspect your strut towers regularly, especially if you live in the rust belt. One indicator of the strut tower starting to give is that your van will lean very slightly to the left. This is how I discovered my rotted strut towers.
Generally, your tower requires attention when it starts to look like this. Note that you can see the aforementioned bulge. My Caravan's strut towers looked slightly better than this when I got them repaired:
When the inevitable happens, it looks like this. Not how the outer crescent of the strut breaks through by the fender at an upwards angle. This is a "better" case, as I have seen other broken through strut towers where the whole chunk of metal from where it breaks through goes off, exposing the top of the strut. In this case, it just cracked and broke up:
Now, don't fret, because there is a fix!
In 2002, DaimlerChrysler issued a TSB regarding the rusting strut towers (
http://img.photobucket.com/albums/v516/Karrmann/CaravanStrutTowerTSB.jpg), and developed a fix that involves putting a cap on top of the tower and affixing it with either pop rivets or a powerful adhesive. Some bodyshop owners I know have told me that the adhesive that Chrysler specifies is rather expensive, and most who perform the repairs either weld the caps on or pop rivet/bolt them on. Add on a dollop of powdercoating, and you are ready to hit the road. My Caravan's was repaired by professionals who bolted/riveted on the cap by the spotwelds and undercoated the crap out of them afterwards.
Now, the repair has come under some criticism because of the fact that it involves just a cap that reenforces the perimeter of the tower, as per the actual mounts for the strut. Lest we forget, however, that the towers always break through on the outer perimeter, with the strut penetrating on an upward angle. As the fix is a cap that reenforces the perimeter, it is perfectly effective. Since it has been out for going on 8 years now, it is very inexpensive, and usually includes the cap and the necessary rivets.
You can get the kit (one side at a time) for $15 a piece. I had mine professionally installed by a trusted body shop for $300. (parts included)
Now, I am not sure of its effectiveness on vans where the strut has already broken through. IMO, if that has already happened, you are best off having another tower welded on, or getting your @#$ on Craigslist and getting a new van.
Still, it is a good, cost-effective solution. With only 133,000 miles and a freshly rebuilt transmission, scrapping my van was out of the question. Thanks to the kit, my baby is back on the road and ready to take me through college!
As per those who are facing the same problem I had, I hope this helped!
