Big block cooling issues

Lord Sparky said

So at what temperature will an engine overheat and cause damage or break down? My 440 (stock radiator and 7-blade fan) normally runs at 180-200 degrees. Was doing a charging test idling in drive for 15 minutes and it crept up to 230. As soon as I started driving, the temp dropped back to 180. When should you pull over?

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It depends on what pressure your radiator cap is and what antifreeze mix you’re running. But even with only a 7 psi cap and a 50/50 antifreeze mix you’re looking at a little under 250*F for boiling. If you run a 12 or 16psi cap it’s higher.

Normal operating temps between 180-200* are perfectly normal. At 230* you wouldn’t want it getting much hotter. And I wouldn’t want to see 230* regularly under normal conditions. Given that you were at idle in drive, and it isn’t partially hot outside right now, I would suspect your fan is a little bit on the weak side for some reason. That’s backed up by the temperature dropping as soon as you drove it, which is a good thing and indicates your cooling system overall is probably just fine.

Do you have a fan shroud installed? Any kind of fan clutch? Stock or aftermarket pulleys? Might have a small mismatch or slight loss of efficiency related to the fan at idle. It would be pretty minor if it’s anything at all though.