Engine overheated

[JimC]

So yesterday I’m driving my roadster about 30 min all seemed fine stopped at auto parts store for about 10 min, within 5 min of leaving temp was 250, stopped immediately and found fan relay was out. Engine sounded fine, no coolant leaks or steam anywhere , oil looks good, not absolutely sure it wasn’t hot before I stopped at the auto parts store, but I know it was working at some point as I saw temp stabilize after it reached 195 on the way there. Did I do any damage?

[GoDadGo]

You're probably A-Okay, but change the oil just to make sure.
Also, consider wiring in a radiator fan override switch.
As for me, my fan runs 100% of the time.
Fans are cheap compared to engines.

Good Luck From The Dark Dart Side!
https://www.factoryfive.com/whats-new/customer-steve-l-graduates-his-mk4-roadster/

[cv2065]

If the water/anti freeze didn't boil...then you should be good to go.

[NAZ]

My F550 with the Scorpion engine runs 245-degrees running up the grades out here in the mountain west -- no problemo. https://www.hotrod.com/articles/engine-oil-temperature/

[Norm B]

As already stated, as long as it didn't boil over you should be OK. A 50 50 coolant mixture and a 16 pound cap should have kept you safe.

Just for your info, boiling creates pockets of steam in the heads and block. These pockets cause extreme hot spots in the surrounding metal because there's no fluid to carry the heat away. This leads to cracks, warped heads, blown head gaskets and rings that have lost their temper.
You'll know pretty quickly if something got hurt. It will start puking coolant and/or making blue smoke.

[CraigS]

I am hopeful you are OK. I did the same to my 351. Kept checking afterwards and finally, maybe 3 months later, I forgot about it. Best luck to you.

[JimC]

I appreciate everyone’s input and suggestions. Yeah that shook me up pretty good, I thought I was keeping a relatively close eye on all my gauges when driving but obviously not close enough, I might need idiot lights.

[NAZ]

Don't overthink this -- you saw the higher than normal ECT and reacted. The 250-deg ECT is not going to make the Earth spin out of orbit and plummet into the Sun. Now I'm not recommending running your ECT at 250, but if that's the worst thing you did I also wouldn't worry about it unless it started puking coolant because you had a lower pressure cap with a higher pressure pump or not enough recovery tank capacity. If you have a typical 50% anti-freeze mixture it will boil (turn to a gas) at 265-degrees under 15 PSI so even a 16lb cap should provide you with some margin from boil-over at 250-degrees ECT. But running that temp vs say 190-deg WILL require more recovery tank volume so if your coolant tank is marginal at your normal temp you may see coolant puke out the catch tank. This will lead to lowering your total coolant fill as coolant expands when heated and the more heat the more expansion.

[rich grsc]

As others have stated, not to worry. Now had you boiled half the coolant out and kept on driving then yes you'd have to worry. Many new cars operate near that temp. I wouldn't even waste the time changing the oil, as the two don't really relate in this case.