According to the 3.5 Monster Manual:

The creature is a little more than 20 feet long, with a body about 5 feet wide. It weighs about 10,000 pounds.

Here's what the Monster Manual 3.5 says:

Heat (Ex)

An enraged remorhaz generates heat so intense that anything touching its body takes 8d6 points of fire damage. Creatures striking a remorhaz with natural attacks or unarmed attacks are subject to this damage, but creatures striking with melee weapons do not take damage from the remorhaz’s heat. This heat can melt or char weapons; any weapon that strikes a remorhaz is allowed a DC 18 Fortitude save to avoid destruction. The save DC is Constitution-based.

 Mind you it used to only be a CR7 magical beast, despite dealing 8d6 damage from its heat versus the 3d6 now, and it did the damage when it hit you or if you hit it with an unarmed attack or natural weapons, but not when you hit it with weapons.

The SRD for 3.5 is free:

https://www.d20srd.org/srd/monsters/remorhaz.htm

The moral of the story is that challenge ratings have never been an accurate reflection of just how dangerous something is. From 3.5:

//Challenge rating is based on a 4 person party. A single CR 1 creature is an appropriate challenge for 4 1st level PCs. They're supposed to win, but they'll have to noticeably deplete their resources like spell slots and hit points. No PCs are expected to die. The PCs can face about 4 such enounters without resting.//

Although 3.5 used a sliding scale when it came to challenge ratings based on the character levels, instead of having a set XP per creature.

I just found this gem of an article that covers all versions of the Remorhaz:

https://www.belloflostsouls.net/2021/12/dd-monster-spotlight-the-remorhaz.html

//And disturbingly, the monster manual also lists what happens when the Remorhaz is aroused. It secretes an internal substance that causes it to emanate intense heat. So much so that any creature in contact with its surface takes 10d10 points of damage with no save.

So, you know, bad news bugbears.//

Or in other words: Don't make [Remorhaz horny]; you wouldn't like [Remorhaz] when [it's horny].

I died 23 times to this thing. My human barbarian Frederick died to the bite and got pierced on his teeth and my fellow aarakocra monk tried to ungrapple me but failed. Then he threw a healing potion at me (as a bonus action, houseruled) and succeded on the DEX save, because I was stuck in his dam mouth. So I took an other breath before I went to downstate for the second time. The monk was scared of course and flew away, he had the mobility feat, so why not. But then he said he would still provoke an opportunity attack since he didn't attack this turn. So this thing attacked...and instead of attacking him our DM said this thing could only attack creatures he is biting on if he has creatures in his mouth. And my mate got me swallowed and was stuck in his belly. Thanks to my luck I got a nat 1 on the death save (secretly). My party then managed to cast the spell "Aura of Life" on me through some godly spell scroll of an former party member. Shortly after they managed to kill that thing and got me out of there in 2 minutes. So I died every round for an other 20 rounds and lost all my hair and basicly got cooked alive. Sadly I didn't become a fire genasi tho

Happens

I'd personally rule it as so

um.. it doesn't seem to have a swim speed, or water breathing... so.. all that melted ice/snow? where did all that go?

One of my level 8 players just one-shot it, lmao.

woooaaah

Challenge ratings are complete bogus 

I'd say this is closer to CR 13

Why does everyone keep fighting these at lvl 5-7? They’re CR 11. I know the CR system kinda sucks, but it’s still important to look at.

I remeber un one or m'y session i has five of Them as pet whit m'y party member

Yes but what does it taste like?

What is that?!

Look guys, the secret to beating these is to be a level 16 party. Then it's easy-peasy! Five at once? Whatever!

We just killed one of these as a party of 3 with a DMPC. I'm lvl 8 the other 2 are lvl 6. 

Would have loved to know that as my o e shot party had to fight 5 of them at the same time.

Quote from DangerBoyo >>

One of my level 8 players just one-shot it, lmao.

 How?!?

Quote from Suspiciousslime23372 >>

Quote from DangerBoyo >>

One of my level 8 players just one-shot it, lmao.

 How?!?

 
Most likely by doing at least 195 damage in one hit
(Made and account just for this)