hi everyone - i'm an e30 m3 driver looking to expand into the e28m5 world, and i have a couple of questions (and hoping for some advice) for the forum...

i've found a sound m5 with a solid history (178k on the clock) that drives strong and handles well - from a test drive. that said, i'd love your advice on things to look for outside of the test drive. my guess is that the engine is bulletproof, but what should i look for in the history records (there are quite a few).

in addition, there's a small rust area on the left rear quarter-panel (adjacent to the rubber molding under the trunk lid - looks like water may not have drained and sat for while). is this an incredibly expensive fix? any advice would help.

thanks in advance for your help and your advice.

The rust you see isn't that had to repair but it also depends on how serious it is. look for rust in spare tire well and at jacking points under the car. Also, rust can be an issue where the bumpers mount. Look for replacement of timing chain guides in repair records this should have been done by now at least once. This is not an inexpensive car to have major work done. PPI is a good idea.

It is probably not that bad if you have a good sheet metal guy who can just cut out the old metal and fab a replacement section. That area is fairly easy to get to and work on.

Check the car for other rust carefully, especially around the rear subframe mounting points . Rust there is what killed my 533i.

The trunk seals on the E28s are a bad design. I had rust starting under mine as the water would sit under the seal. I removed old seal, POR-15 the channel, and installed new seal using a lot of the contact cement. While your at it check the taillight seals, and license plate light seals, they like to rust there too.

Did POR15 work for you?

The trunk seals on the E28s are a bad design. I had rust starting under mine as the water would sit under the seal. I removed old seal, POR-15 the channel, and installed new seal using a lot of the contact cement. While your at it check the taillight seals, and license plate light seals, they like to rust there too.

I've used the POR-15 starter kit which has everything you need for prep (except for some sandpaper) and paint. Just be careful to wipe the lid area clean before putting the lid back on or it'll be tough to get it off next time. Great stuff for knocking out small areas of rust. I think the starter kit was under $30 or so shipped.

Did POR15 work for you?

Worked great! Also POR 15 the battery tray, and will be doing the spare tire well soon. It's all about prepping it right. And when you put the lid back on I used a small plastic back so it wouldn't seal shut.

Jay