I’m considering purchasing a 2017 expedition king ranch. I see a little bit of rust looking back toward the rear differential. Not much on the frame though. Is this bad rust? Should I be worried about it?
It looks like it is strictly surface rust. I wouldn't be concerned about that.
Two issues:
Issue 1: it’s all cast iron in picture, it’s surface rust, no trouble.
Issue 2: it’s a 2017 Expedition, … how come these castings are so rusty, already? We here in Canada drive in ice and snow and salty brine covered roads for more than one halve of the year with same casting exposed, … and even 10 year old cars and trucks don’t show that much rust on those castings!
And so, … never mind a surface rust on cast iron parts, … but have a real close look at other parts - forged steel parts: frame, subframe; formed parts: sheet metal parts, body parts, clips and washers, … the rest! These may be painted and don’t show much rust yet, … but do they show signs of rust, too? I suspect this car was immersed in water, … perhaps in salty water for a while, or often driven in one, … or something like that, … and is most likely rusting from inside out quite rapidly too? Dunno, … but under normal use condition cast iron parts don’t rust so quickly without accelerant, like prolonged immersion, or very frequent immersion. fwiw.
F.S.
Very informative. Thank you so much!
If you choose to buy this, and you're up north, get the underside "fluid filmed" before winter.