Is this quite typical on a winter driven 1989 240?
You can see in on the right hand side, where the rear passenger footwell is, that it has rusted through. I stripped the interior carpet to hunt for any more rust, and patch the hole.
Did you spray under the car at least once a week? That seems like a bit much. I drove my 300zx once through the winter and I got a couple bubbles on my paint. And I know I got more under car rust, but…not like that.
You dont have to worry, its not like your car is going to implode. But you know…one hot summer afternoon. You can always get under there with an sos pad and make life beautiful 
yeah it looks worst than it is i think. i still have to check near the downpipe and around the cat. supposedly the heat from the exhaust removes the undercoat and exposes the metal.
you know with all those subframe parts you can eliminate the rust using that chemical w/ positive charge to the liquid hey? I can’t remember what post it was, but its on this forum somewhere. Kills the rust without eating any good metal.
Jeeez
Look like its from ontario
I out have holes in the floor scrap it
Take a hammer and hit your frame rail, i will give you 100 bucks if the hammer doesn’t go right thru, The worst spot is on the drivers side right after it sloped down from the engine bay
yeah it’s mostly on the sub frame components. but that rust removal technique weakens the metal, so i’ll just replace them with some cheap megan racing parts.
I would just worry about the frame rails…
frame rails are still holding, or so i believe. i’ve had the car held up via the framerails sitting on axlestands a few times already, and they havn’t crumpled through. lol.