IS200 rusting chassis rail - what can I do?

[IS Gen 1]

My IS200 had a rusty rear outer sill which had a new bit of metal fabricated and welded on for the MOT last year. The welder told me that the chassis rail was rusting and that it'll probably be about 5 years until it's rusted all the way through. That sounds pretty bad, wouldn't you say? Anyway, I've looked at the rails from underneath the car and they seem ok. So this rail must only be rusting from the side, which is where I can't see because it was welded up there.

So now I'm trying to figure out what my options are and what this could end up costing. Can a chassis rail be safely repaired or does it need replacing? Any idea what it would cost to have that kind of work done?

Cheers ;)

[steve2006]

Hello and welcome to the LOC.

If the rust is as bad as the MOT tester is saying then the whole section would need replacing.

You can only effectively weld a patch plate to clean metal so he must have taken the repair patch far enough away from the rusty area to enable this.

Five years is a subjective estimate, it depends on many things for example is the car subjected to winter road salt, is it garaged or left out, do you jet wash the underside regularly.

I would monitor the situation and wait and see what happens at the next MOT if there is no obvious further damage evident.

[IS Gen 1]

Thankyou for the reply :)

It failed the MOT on the sill before the welding was done but the tester said nothing about the rail. I just think they didn't notice it as there wasn't much of a hole at that time. they just showed me how brittle it was in that area by poking it which made some rust fall off. I took it to a welder elsewhere who told me after he'd done the welding that he'd noticed the rail was rusting when he was doing the work, so I think it was only after cutting a chunk of the sill out that it became visible.

It's not something you can even see because it's got a bit of metal welded over it so I can't really inspect it and neither can an MOT tester.  I'm scared it's going to continue to rust under there and just break one day. The car is kept outside near the coast and rust is quite a problem on a lot of people's cars in the area.

I'm guessing the best idea would probably be to get a new rail in there. I just have no idea what that would cost and whether it's worth me keeping the car. Any ideas on the cost of such a job? I'm trying to find places that can do the job but the ones I've contacted so far have said they don't do that sort of work. I suppose it's a bit of a big deal to do this type of work.

[IS Gen 1]

Just thought this was worth a quick update. Apparently there is no chassis rail seeing as it's a unibody design so I don't know what the welder was talking about. Hopefully nothing too serious.

[steve2006]

There are “chassis rails” as such but these are sectional parts factory welded together along the length of the car and then welded to the other body components such as sills and floor pans to form one piece (hence monocoque or unibody).

Most cars are built this way now because it is cheaper to make than having a separate chassis and body which can be lifted off the chassis.

 

[Razor61]

Have a look and read of the topic below, it may help.