Max Operating Temp before Ka-clunk

[98K35Ox]

I've got a 98 k3500 that just had a Vortec 5.7 dropped into it with less than 50k miles on the engine. Trouble is, over the weekend through some really bad luck the radiator vented almost all coolant while on the highway doing 80 mph, and it quickly went from holding steady at 192° to 220° at the coolant temp gauge via OBDII and it pegged over 260° on the dash. It stayed this way for at least 2-4 minutes while we navigated off of the highway (heavy traffic) and coasted down the shoulder.

The oil wasn't milky, but it was definitely burned and wasn't as clear as when the oil was changed. Changed the oil again today after returning from the trip, and it stayed very clear and clean, but the oil plug had a ton of metal on it when it was removed.

Anyone have any experience to go on how screwed we are? We've had several TBI GMT400s, but this is our first Vortec, and it's the only one that's ever gotten this hot.

 

[magimerlin]

Tbi or vortec, it doesn't matter, from below the intake and down they are the same exact motor(yes heads are different flow wise).. if you over heated it and there was a ton of metal shaving on the drain plug. It's just a matter of time.. plan on a total rebuild or a new motor and just drive it like you stole it till it blows up...lol...

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[MIHELA]

I overheated my TBI enough to boil coolant in the res, and it trashed my radiator and cam bearings.

 

[retorq]

Vortec heads at 220+ for almost 5 mins with little to no coolant in them, you more than likely cracked one or both.

 

[Biggershaft96]

Id stash some cash back or invest in a backup motor if you can get a good deal on one. But until it shows signs of failure (knocking, excessive smoke, low compression, etc) id just run it