Damn, side of the road with a blown serpentine.
 

Sigh. She's much happier when she doesn't have to run at -22ºc.

The belt seems to have blown. Some pieces off the edge loose in the engine compartment and the belt is hanging loose.
Bit of a panic when I lost steering, alternator and the fan. It overheated before I figured out what the hell was going on.
I've limped it home, and will see what's going on tomorrow when I have light and it warms up to -8º.

Question:
The pressure release on the coolant cap has popped up. How do I reset that? Does it just push back down? Haven't had a real look at it as it was (ironically) too hot.
I'm hoping it was just old belt and stiff everything that runs off it that caused it to fail, but I'll take any recommendations as to what to look for! :)

I suspect there will be more to come tomorrow...

I think you can push it back in but get a new coolant cap because of the age of your Disco. I got an ‘01 Disco 2 also and I bought a new coolant and gas cap due to its age.

Same thing happened to my truck back in August. The serp belt self destructed. Just install a new belt and top up the coolant. I don't know what you mean when you say "the pressure release on the coolant cap has popped up." The ones for a DII I've seen don't have anything to "pop up." (Maybe post a picture?) In any case just "pop it" back down and observe what happens with a new belt and the coolant topped up.

Okay. I've had a look...
"Popped up" was a roadside illusion of looking at the cap with coolant steaming out of it in the dark and snow. It seems fine. Barely lost any coolant, so I'm not as worried about having wrecked anything asI was last night.
Everything I can reach seems to be turning appropriately, so happy about that too.

So the questions for the group:
Do I have to take the fan off to remove/replace the belt?

And the tensioner pulley: I think it's what went wrong. It's loose and floppy on it's bearings. I've never felt one that wasn't under tension, but it doesn't feel right to me. Loose on the shaft...

I'll post a video.

Nothing has to be removed to install the belt.
If the tensioner is dead, only one bolt holds it on.
Both can be replaced in 5 minutes.

Worked posting a video out (I hope). Sorry about the poor lighting, but I think you get the idea:

Thank you sixpack for that. Excellent to hear about the fan, and that illustration is just what I needed.

Yes sir, you're welcome.
Good luck with it.

I had to replace my tensioner pulley a year and a half ago. I got it at Advance Auto for $20.47 including tax. The part number is Dayco 89054. Made in USA.

I just noticed you are in Toronto. Hopefully any local parts store will have it in stock for you.

You'll need a 15mm socket to turn the tensioner so that the belt can be fitted to the final pulley. The tensioner spring is pretty stout so I use a cheater pipe over my ratchet handle for extra leverage. Special long-handled tensioner wrenches are sold but you don't really need it.

Removing it may make your life easier.

If you've removed your fan before and have it down to an easy science it only take a couple of minutes to remove upper fan cowl and fan. It makes replacing the belt and pulleys much easier because the access is vastly improved. Removing lower fan cowl may help too. Same goes for stat/hose changes or any other inspection or work needed at front of powerplant.
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