Balto· Premium Member
No, it's a metallurgy problem. The cam keyway chips and it eventually slips on the cam gear. I'd need to see more spin camshafts to confirm, but it definitely isn't a cooling issue.We have no direct evidence of it without testing, but after reviewing camshaft snap stories a few years back I noticed there was speculation that it was oil starvation. But some photos showed clean engines which suggested that if this were a cause, it might not be the only one.
We asked @CherryBomb what her coolant tank looked like when she started her engine swap for a snapped cam, and I think she reported that it was dry. It has been reported that the temp gauge is insensitive to elevated temps. And when a car needs burping, the air trapped is at the highest point, in the head.
So could locally elevated temps in the head occur from an unnoticed slow coolant leak? And can that lead to bearing failure, seizing and a snapped camshaft? We won't know without testing.
But since I don't want to find out, and with what may be circumstantial evidence, I decided to mark the high and low temperature coolant points on a piece of tape stuck to the reservoir, and have a sticker in the fuel filler area reminding me to check the level at every fill-up. Because at 200K miles, a leak could spring up any time, something we also read about here. I check my oil level too.