I've noticed some rust that's in the engine bay on the driver's side wall and frame area,





The rest of the engine bay was painted black sometime before I got it, but this side wasn't. How bad is this? Is it something that can be fixed? It isn't perforated anywhere and doesn't seem to have any cavities even. What could even be done for this?

It doesn't look too bad. The folks here who know about the use of POR could give you some guidance, but it looks like it can be rust neutralized and painted, if you can get a brush down there without removing too much stuff. Or just remove a bunch of stuff!

Not even sure is you need the POR15. It would not hurt anything. The POR15 is an expensive product and your metal does not look bad. It looks like some of that rust may have been caused by brake fluid based on the second pic. A good cleaning, etching/rust treatment, some primer since it looks like bare metal in places and rustoleum should work just fine in that area. Make sure you clean the area well before the primer coat. Tape up or move anything you don't want paint on.

i still have some leftover paint from back in 2000 its a match to the color under my hood
i had rust there last year,clean it up and paint it.i used a brush,and will double check it this year

I see all that rust came from leaking maters cylinder that was on the car. take 80 gritt knock off the rust spray paint what you can.. Make sure you kill the rust before you cover it. You put POR on it your covering the problem not fixing it.

i was changing my master cylinder and booster
but the rust was buy the steering box
a few years ago i cleaned up the Ebay with hand cleaner,so when it came paint i needed to finish cleaning around the box
all and all it looks better than it was

Thanks for the replies guys! I'll go at it with a wire wheel and get down to good metal best I can and treat it and paint it. It most likely was from brake fluid, the master Cylinder had issues when I got it and leaked.

yup,and you can prime sand reprime resand to soften the look any pits from the rust