I unintentionally redlined my car yesterday - is it likely to have done any damage? It's a diesel engine which redlines from 4500 rpm and it probably went no further than 4750 for a few seconds.
No you are OK. I redline my 94 Civic all the time. ALL THE TIME.
It is probably "better" that I don't but in general the ONLY problem is that the VALVES can class if I OVER rev the engine. And they usually build in a buffer (head room) to the redline limit.
Also if you just hit the gas and redlined it , the engine management would have cut off the fuel before it reached critical RPM. But if you downshifted, and redlined, and over-revved it, that is just about the ONLY time you can do serious engine damage.
Have fun,
Good Luck...
P.S. NOTE that I never redline my engine with dirty oil. It is worse to drive with dirty oil than to drive you engine hard (with good clean oil).
P.P.S. I'm 45 and I've been driving sticks since 16. So I've been doing this for a LONG time - no problem