Sorry to hi jack.
not sure about the lx's hope they do something!
had a '85 m body squad had similar prob frame rotted out due to the log convert right by the rail both sides car otherwise mint eventually it started sagging on front clip due to rot! miss that ride...

I don't think that was a hijack, it's interesting that a similar heat caused rust perforation problem to what happened to the frame of my Magnum RT is nothing new.

Out of curiousity, how how do catalytic converters get during operation, especially in city traffic? I wonder if some kind of coating (ceramic? Header paint?) could be used on the LX frames to protect the factory e-coat from burning off and leaving the bare metal exposed?

My neighbor gave me a roll of header wrap to try if/when I get the frame fixed on my Magnum. But I don't know if header wrap would hold up to catalytic converter temps, or could possibly raise catalytic converter temps high enough to damage them. Anyway, finding a way to prevent the burn-off of the e-coat on the frame is food for thought...something an engineer at Chrysler should have thought of and not left to LX owners to figure out on their own.

LX owners should be pushing Chrysler to inspect and find a way to protect their cars' frames before they get cooked like mine did.

I have seen the cats get up to 1800 degrees, while checking the vehicle out on my snapon computer....That was holding the RPM's around 2000 rpm's

I just read this post on the 'LX Forum' from a gentleman regarding his 2006 Magnum in which he found the frame was starting to rot in the same area adjacent to the exhaust manifold/catalytic converter flange as my 2005 Magnum did.

He wrote, "I have a 2006 R/T AWD . . . have 180k km on it. Had it since new, driven year round. Just had a look and can see surface rust on the frame rail area that is across from the exhaust manifold flange outlet . . . worst of it is along the bottom of the seam where the inner fender is welded. However, took a screwdriver to it, and it is solid. .."

He is lucky his frame isn't yet perforated, but how many of these cars are on the road being driven by unsuspecting owners? I sincerely hope Chrysler will act and get all LX vehicles inspected, and if necessary repaired and/or modified in some way to prevent the problem from occuring, before someone gets hurt or killed when heat from the catalytic converters burns away the e-coat on the frame of thier LX vehicle, rust sets in and the frame eventually lets go.

Found this in a police magazine. http://patch.com/ohio/brecksville/rust-issues-on-police-cars-city-department-to-switch-825b600f43

Just had my friends 2004 Hemi 300 on the lift, frame rails were mint with the only rust on the vehicle being around a frame jig opening near the R/R tire. Even then it was slight, typical rust you see there.

New England car with well over 100k on the clock that gets used year round.

Glad you checked the car and it was ok. People who have contacted me with the same frame problem as my car next to the catalytic converters have either lived in busy cities or are in the habit of leaving their car idling for a long period with the a/c or heater on. LX cars in rural areas, or those that see mostly highway driving, don't seem to get the cats hot enough to cook the e-coat off the frame.

You know what, its a unibody car. The frame you keep spouting off about is probably a 16 gauge channel spot welded to the floor pan. The job is going to require removing at least the seats and carpet, and may involve a consel and dash removal because any fix is going to require welding to the floor pan.Depending on how far up the firewall the repair will have to go, there may also be wiring that needs to be removed.

If i had to remove all the interior, I would do the repair from inside the car, one side at a time. Zip cut the floor and the damaged frame rail out of the car. Fabricate a new frame section to replace the rusted area (I would use an 1/8" wall square or rectangle tube if the size was close) and weld the new frame rail inside the original frame. Then weld a patch onto the floor pan. Repeat the process on the other side. Seam seal and paint the floor patch, replace the interior.
From under the car, if possible, seam seal the edges and paint the repair area, then add the late model heat shields.

The repair area will always be there. Structurally, it will be nearly as good as originally designed, and infinitely better then before the repair. The repair will probably out last the car.
No need to pull the motor. There will be as much time in removing and replacing the interior as the repair will take. I'd do it for that $1150 estimate someone else first suggested, and I'm not scared, I've actually repaired cars that were rusty. If you want to save some money, pull the interior before you send the car here.

After I do the first one, the price might be adjusted up or down. I'll be waiting for the LX Platform cars to be lining up on the street in front of my house. Gene

What a great idea you have of how to fix the problem! Where are you located?
I've been using the 'frame' reference for lack of knowing what to actually call that part of the unibody structure. In talking with Chrysler they called it 'frame structure' but is there a more accurate way to describe this area?

Location? Freeport IL, 120 miles west of Chicago IL, 20 miles south of WI, and 60 miles east of IA. Probably a long way from you.


The frame structure has been incorrectly called the frame on Chrysler unibody cars since the mid 50 when they were first produced. The reality is that the frame structure more closely resembles a frame then anything else. The "frame" name has transcended to all makes of unibody built vehicles, so I guess that is about as correct as anything other then actually calling it the "frame structure".

In simple terms, a unibody "frame rail" is a series of formed channels with flanges on the open ends facing outwards. These channels have the flanges spot welded to the floor pan, to form the "frame". The channels are generally made in sections, and the sections are spliced together. The splice has one end of the channel swedged down to fit inside the 2nd section and the splice is spot welded together. These sections are then spot welded to the floor pan. In locations of high stress, the channels are usually reinforced with a slightly smaller flanged channel the fits snugly into the original channel and both channels are spot welded to the pan. The two channels may be welded to the pan separately, one on top of the other, or both welded to the pan together. The floor pan may have an additional flat plate welded to the top of the channel flanges and then the pan will be spot welded to the plate. I have also seen places where a 3rd layer of channel is added to the outside of the original flanged channel.

It should be obvious the places with multiple layers of speed are great places for rust to start. Condensation or water can be trapped between the layers of steel and begin to rust. As the area passes through the hot and cold cycles, the water separates the steel layers and allows more moisture to become trapped, increasing the speed at which the rust develops. If we add an additional heat source (converter) we can cause the trapped water to expand by boiling the water in the summer, and by freezing the water in the winter, there by reducing the time frame it normally takes for the rust process to damage the integrity of the steel.

The repair of a damaged "frame rail" is simply a matter of removing the floor pan in the area surrounding the damaged rail, removing a section of the damaged area and replacing it with a fabricated replacement section. The new section is welded into place, along with whatever reinforcement pieces are required, and the floor pan is repaired and welded to the rail flanges.

Most unibody cars have a portion of the "frame" that is made of heavy gauge steel. This structure is generally used to mount suspension, motors, and transmissions and is often refereed to an an engine cradle. The cradle is usually mounted to the unibody structure at reinforced locations with bolts through a captured nut welded inside the frame rails. Gene

Old post but same issue... my Magnum is on her last legs... Both front frame rails rotted thru...Very clean car no rot anywhere but next to the Cats...

I've retired now, but the fix would still be the same, if the damaged "frame" is not easily accessible from under the car. If the damaged "frame" is easily accessible from under the car, the job is not much different then replacing a "frame rail" on a Cuda, Challenger, or any other late 60s or early 70s Mopar car. Remove anything in the way, drill out the spot welds to remove the damaged part, then plug weld the new part in place, paint as needed, replace the parts removed for access, and carry on with life. You may have to fabricate the new part, but that is part of the game for any vehicle that replacement parts are not made for.

i find it interesting that we don't have any concern about replacing the frame rails on the performance era Mopars cars we love, but somehow consider the modern Mopars we love to be unworthy of frame rail replacement.

For that last guy that posted, I'd probably pay you scrap price for your "rusted out junk." Gene

I remember this post! The use of the word perforation was abundant at the time....

My 2005 Magnum awd is rusted in the same spot. Along with the front cradle, the left rear hoist pad structure, drivers floor pan, drivers side rear floor pan, lower battery box. Except for the areas by the converter I have repaired the rest. The outer body and the rest of the floor pan is in decent shape. Some bubbles on the left rear 1/4 panel but that's it. There's a lot of other structure by the converters. The metal where it rusts is relatively thin. I peeled the rusted metal away on mine. It looks more like an inner fender than structure. In my opinion there's not a lot of structure loss there Not saying it's great. But I'm not afraid to drive it.
Doug

My 2012 Challenger R/T is always put away during the Michigan winters. Never driven in the snow. My under body and frame rails are still mint and rust free. However, the driver side quarter before the rear tire is starting to bubble the paint and show signs of rust. Bums me out everytime I see it knowing that I have taken excellent care of it, but yet still is starting to show rust. I understand it is now a 10 year old vehicle. These vehicles must hold water, dirt or debris in these areas?

I have 06 Magnum RT AWD . . . frame rust where talked about - but it is surface - still all good metal ! . . . as for rust on the quarters . . . well, yeah, right where the bumper meets up to the quarter, on the front part of top of bumper, just above there - sure I drive car year round, but always wash the wheel wells out. The rust bubble was "maybe" 1/8-1/4", on both sides, same spot. Took to body shop and had them cut out the metal, weld in metal, and repaint. I figured after 14 years, (I had done couple years ago), that $2k on body work/paint was pretty cheap maintenance ! . . .all depends if you want to keep the car or not . . . really no difference than our "classic" cars . . .

in my opinion, panel rust on some of the newer stuff is caused by the foam that is installed to keep noise and rattles down, trapping moisture.
my caravan, although a 1999 model year, has a bunch of that stuff in the rockers, dog legs, and other areas.
as i have seen how these things rust, i drilled holes above the foam, took all the rubber plugs out of the door posts, and removed the tail lights, then had my buddy hose in his "secret sauce" oil.
this totally saturated the foam with oil, and my "bus" is only showing a few rust flecks where the paint has been knocked off by door dings.
while the foam does a pretty good job of keeping the interior quiet, it sure does a number on the sheet metal by retaining moisture.

I think Moparx is onto something with the foam. The trucks had this issue because of the foam in the beds.

Also, as far as frame rust; I believe any car that's living in snow states with salt is going to be prone to this especially cars ten years old or more. They either have to be put away for winters or receive one of the better treatments to be protected.

It's because Chrysler sprays expanding foam into the rockers & quarter areas like where yours is rusted - to reduce road noise. Even rustproofing cannot get around the foam. The spray-in foam is a TERRIBLE idea - major moisture trap.