Well I have an interesting one for you guys.

I got in my truck this morning, 98 Tacoma with the 3.4 V6, and headed to work. It overheated on me. So I pulled off and there was coolant everywhere. Pretty sure it's the water pump.

Here's where it gets interesting. It was around -30 with windchill last night. I looked in the overflow to see if there was any fluid left in there and it was frozen. This really concerns me.

What do you guys think I should look at besides the water pump? I'll be doing the whole TB service, even though the current TB and water pump are less than 30k old. This truck was given to my wife and I from her dad who lives in Las Vegas. Is there a chance that they use a different coolant out there and it's not rated for that cold of a temp?

I'd start off by immediately getting the coolant tested, you can pick up the kits pretty cheap at any auto store. If it is the coolant freezing in the block then it needs to be replaced asap before you end up with a cracked block.

How far into the drive did the truck overheat?

Honestly if its that aftermarket green crap with any vehicle I buy I flush it out and put toyota red in. Partially because its just about the best coolant you can buy, and partially because coolant is one of the most neglected fluids in most vehicles. God knows what kind of nasty mixture of top up fluids end up in there along with rust particles over the years. I've heard a lot of storys about people topping off their rad with washer fluid because its also colored and comes in the same kind of bottle.

Good news, wind chill has no bearing on mechanical objects.

Bad news, if the "antifreeze" froze in the overflow, it probably froze in the block. This freezing can crack the block or heads. Or just popped out the freezeout plugs and when it heated up, the antifreeze drains out. Or it froze and tore the impeller off the waterpump.

The overheating might have warped the heads or block, or maybe nothing.

You are going to need to drain the whole coolant system, if it isn't dry already. Then refill with a fresh antifreeze/water mix. At this point, run the truck and see if the antifreeze leaks out anywhere. Keep an eye on the temp gauge. If running at a normal temp, see if the radiator is hot or cold. If cold, the pump isn't working or the thermostat has failed closed.

Thanks for the info guys.

It has Toyota red in it. My father-in-law only got service done at the Toyota dealership in Vegas. I'm going to test the coolant, but have to drain some as it's low enough that I can't see it at the top of the radiator. Maybe I'll just drain it all and replace with green, since it's cheaper, until I figure out what really happened.

Oh, and it was about 3.5 miles into my 15 mile drive. About to head outside to drain it and see how much I get.

Well, that's not good.

Got it drained and only got about 2 quarts. Not surprising. The surprising part was that it tested with a freezing point of +6 degrees.

Very concerning for multiple reasons. I'd put it in a heated garage overnight with the drain open. Then refill it with water (assuming you have a garage) find the source of the coolant leak and hopefully fix it. Then flush and fill with toyota red.

Gerdo is right on point. Although if your antifreeze froze it means its not a 50/50 mixture or its bad coolant period. You can test but I would go ahead and flush the whole system and replace with 50/50 red/distilled water, replace water pump, tstat, hoses, radiatior and radiator cap. I wouldn't take the chance at running the engine with any of those parts becuse they're all alluminum and could have cracked/broken. If you're lucky the block isn't cracked and you can be back on the road with a couple hundred bucks invested crossing your fingers. I just had a buddy who had this happen on his mercedes a week ago, we did all of the above and luckily it did the trick.

I went and got cheap antifreeze to check for leaks. I filled it up and started it. I let it run while and watched it very closely. No leaks. It got up to temp and started blowing hot air. I let it idle for another 10 minutes after getting hot. The temp needle never moved past half way. Didn't see any leaks or anything.

I'll flush this out and put in Toyota red once I'm 100% sure there's no other issues.

Thanks for you help guys.

Any way to test your radiator cap to see if it's holding pressure?
One possibility that occurred to me dug out of the past. A couple things my Dad passed on to me based on his experience as a garage mechanic from the 1930s-1970s. If there is some anti-freeze in with the water it usualy won't freeze rock hard. Some times when driving if your coolant is good enough for cold it will gel in the radiator when your driving and when the thermostat opens up there is no place for the engine coolant to go so it over heats, over pressures, and blows out of the radiator cap making a mess. Based on the frozen coolant in the over flow jug this is a possibility of what happened.
So based on what you've found, other than making sure your coolant is strong enough, and checking all fluid levels twice a day for a couple weeks I wouldn't worry.

Thanks for the info. I checked fluid this morning and everything was fine, and not frozen. I'll be checking everytime I drive the truck for a while. I was also thinking of just getting a new radiator cap, just to be safe.

Thanks again for everybody's help.

Yes.
Either replace the cap with a new one. Or have a mechanic test it. Or some of the smaller auto parts store/machine shops might have a cap/system pressure tester.