Got my 355 home with the luckiest of radiator pipe leak fixes

TL;DR: left radiator pipe cracked; with the luck of the Cavallino I temp-fixed. What should I check next?

Planned a day trip to Mt. Rainier with the oldest kid (him in his Jetta GLI, me in the 355). It's been hot (for Seattle) lately and it was in the low 80's at drive time, about 11am.

Even at 55-60mph, I noticed the water temp gauge staying to the right of its usual home, pegged at 190. I figured it was the slower parts of the drive and the hotter air.

About an hour out, we pull over. We're at the last point of "civilization" before things get National Park-y and there are no services or stores for miles. I pop the cover just because I have a nagging feeling.

There is coolant sizzling everywhere on the front left quarter of the bay; it's steaming off the headers, pooling on the under tray, generally a green sticky hell. It is still spitting out of a crack in the bottom of the outbound (I think!) plastic pipe - it's the only easily accessible pipe of that system.

I freak out a little bit and then just let the car sit and cool. Temp never got in the red, but it was a a notch and half over from 190. Oil temp never budged.

Incredibly, the general store next to this small rest area has 50/50 coolant and 500°F leak wrap tape. I refill the expansion tank (which looked close to empty but not bone dry), towel off all of the coolant and residue I can get at, and once that's done wrap the leaky section. That tape really does a trick; it bonds and seals right on contact.

We immediately start the 70 miles back home, hoping we can make it. At startup, bone dry. After 5 miles up a hilly switchback, still bone dry. After about 10 minutes the needle swung quickly back to 190 and everything behaved like I'm used to. Home without incident, a totally ordinary drive.

What should I do next:

• I think this is the pipe. Can we replace that by getting the car on a lift and getting the wheel well open? I really don't want to engine-out for one lousy pipe. (How long can I trust my cheap fix? Trust me, not planning any road trips.)
  
  
• I don't think the rest of the engine was heat-stressed, but is there anything I should immediately inspect or worry about? Pump was replaced during 2/17 major. Radiators have slight corrosion, but fans operate normally. Is that 50/50 coolant okay or should I flush the system? I couldn't tell from the manual if it's supposed to be a different ratio or pure antifreeze.

Have to admit I'm hardly a mechanic but I felt awfully lucky and a little proud today. You're not helpless if you slow down and think through a stressful but straightforward problem. (But again, damned lucky to be where I was when I spotted the trouble.)

 

(Thank you @fatbillybob – I admit I secretly wondered whether this was Stooge-worthy. )

I probably need to add more coolant than I did to get back to normal so I'll follow that procedure. Is the fill line in the tank right where the neck ends? It extends down into the tank a little bit? And is that the line when cold, or at warm idle?

That back-of-head tip is great; I had been wondering how much pressure the system is under nominally. I figured it wasn't too much.