[flybywire]

My 2015 235 has corrosion on the oil cooler line, right at the spot where it makes contact with the insulation on the bottom of the plastic engine cover (removed for photo).

Is this a common issue?

I removed most of the rust with emery paper and treated with WD40. Any suggestions for a more permanent solution?

[cristo]

Get the rust off and provided you don’t
go too far through the pipe, use some
Rustoleum high temp primer or some POR-15.

[MarcoZandrini]

It's odd that the rust is in that specific area. It looks like something has been dripping on the pipe. What's above the pipe?

[flybywire]

The plastic engine cover has rubbery insulation glued to to bottom. When the cover is installed that insulation contacts the pipe at that point. I suspect it captures moisture, and during winter here in the DC metro the moisture might be road salt spray.

That's my theory - was looking to see if others have seen the same.

[flybywire]

@cristo: Will do! I had never heard of POR-15. the manufacturer has a small-area kit at a reasonable price.

[MarcoZandrini]

Originally Posted by cristo

Get the rust off and provided you don’t
go too far through the pipe, use some
Rustoleum high temp primer or some POR-15.

Corroseal work fine, too.

[bongko]

is that a byproduct of living near the sea?

[flybywire]

Could be sea salt spray - I'm second owner and don't know car's history. I'm too far inland for that, but here in DC area salt is applied to road surfaces every time there is more than about a one percent chance of snow.