[Verdoro 68]

Serrated flanges are probably a good call. I've been running this setup with the lock washers for years without issue, but I'd like to avoid this potential problem in the future.

Looks like I had another one that was close to giving out in the similar spots. These are gold, so now I'm wondering if I did find grade 8 washers at the store after all. It's getting bad when I can't remember yesterday. Either way, doesn't really matter now.

[Gach]

I don’t blame you on ordering new radiator. God we can’t even get decent washes. Who would ever thought.

[mgarblik]

I have had some split washers, (lock washers ), break like that in several different situations over the last 3-4 years mostly. Has to do with poor quality off shore suppliers in my experience. One I remember well is an engine stand I was assembling from new. Had several washers split just like that. I ended up throwing all the hardware away and replacing with Domestic nuts,bolts washers. The other one recently was a replacement upper ball joint, Moog branded. The lock washers fractured while tightening. The only thing common among the failed washers was the ID and OD of the washer had square shoulders. The domestic lock washers had more rounded, softer shoulders on them. They were also slightly thicker. It's just amazing how virtually everything from China is complete crap, right down to the fasteners that hold their garbage together. Sorry for your damage. Beautiful car to have some little rat bites. You are more even tempered than me it seems. I would be extremely pissed by this. Congratulations on getting it back together and back on the road.

[Shiny]

That must have been frustrating after winning such a battle over your leak.

A brittle washer would be totally unexpected for me, even if Grade 8. Maybe hydrogen embrittlement? Whatever it was, I'm sorry it happened to you... you didn't deserve to be hurt by something so small after the effort you put into something complicated.

I truly hope it's all behind you soon.