[jay-rock]

I just bought an 07 328xi. The exterior is in great shape.





It was in NJ for several years. I've always lived in FL and never had rust. This car does have some rust on the undercarriage. How serious is this?

This is not a daily driver. If I avoid driving in the rain will it still get worse?

[mxchris727]

That's all surface rust; nothing to worry about. BMW stopped rust-proofing their undercarriages in 2003 to meet new EU requirements. As long as you don't see rust on the body of the car or under the paint, it's fine.
Mine looks just like that even though it has been garaged it's entire life. Just a fact of owning cars in the Northeast. What I do occasionally is go under with a wire brush and remove everything I see. Then, I spray the area with VHT rust converter to keep it away. It has no affect on the metal; just makes it look cleaner.

[jay-rock]

Thanks for the reply. That's great to know. I've been stressing about this with all the horror stories I've read about rust. After using the wire brush I can spray VHT anywhere? Don't have to avoid certain places or plastic parts?

My mechanic said it may be worth spraying some PB Blaster on the bolts. Is that just so its easier for him to loosen the bolts if need be without breaking them?

[jay-rock]

"BMW stopped rust-proofing their undercarriages in 2003 to meet new EU requirements"

I thought they did more rust proofing with the e90's than with the e46's? Still learning.

[tlow98]

Originally Posted by jay-rock

"BMW stopped rust-proofing their undercarriages in 2003 to meet new EU requirements"

I thought they did more rust proofing with the e90's than with the e46's? Still learning.

They did more rust proofing to the body with galvanization (similar to Porsche), but they stopped spraying the cosmoline(?) on the underbody.

Harder for the mechanics. Better for the beauty. I’ll take the change - paint surface rust is so ugly.

[tlow98]

What’s you’re looking at here is on the subframes and bolts - much easier to remove than any paint related rust!

[Big Mexican Women]

that's not anything serious. nothing to worry about.

paint looks great!

[mxchris727]

Great looking car BTW. Yes, you can spray that rust converter on anything metal underneath the car. Avoid the plastic under-body, wires, lines, and sensors.

Here's a screenshot from ISTA:

[jay-rock]

Thanks, mxchris.

One more question. Do you lift your car when you check for rust? I don't have a way to lift it and think I may be missing some parts. A lot of parts are covered by plastic so I assume those are safe. Any parts in particular I should be focused on?

[e90yyc]

Like others have said, I wouldn't be worried about any of that. Very superficial.

Where I live they use tons of salt on the roads, so it really puts the rust protection on these cars to the test. The sheet metal is extremely well-protected, but absolutely I see the effects on steel suspension components etc

[jay-rock]

I thought this would spread and eat deeper into the frame every time it gets wet? You guys seem so laid back about it I must be wrong. Forgive my OCD, ha.