Don't just thumbs down for the concept, his clears are godlike late game, he doesn't have to use HP pots first clear, with good aim his ganks are decent, so there is purpose to choosing him. Try it out yourself, tank the turret right before it dies.

I'm no expert at BBCoding, and there is little to no BBCode in this guide. Please don't downvote just for appearence, as I spent a long time on this guide. Thank you for considering.

If you can tell me how to BBCode better in the comments, I would greatly appreciate that.

Pros

Official Swagmaster of the League
Underestimated, can also be a Con
Blue Build OP Heimerdinger 2013
Can Lure Children into Bushes and Shoot Missiles at Them
Has Great Poke with Missiles
Great Burst Damage
Has a Stun, Although it is Unreliable at Best
Can Place Turrets on Camps, and Then Go Away
Extremely Fast Jungle Clear Times After Initial
First Clear Can Easily Take 0 Health Potions

Cons

People Will Flame You if You Do Bad (Which You Won't)
Have to Practice with Friends to Get Comfortable
So Squishy
Too Hot for Anyone to Handle

Start Blue Buff, get a smiteless, then go to directly to Red Buff. After that, you should be level 3, so go and either: gank with your e, watch your enemy team surrender @ 20, or farm the jungle if no opportunities come up.

Flash: OP DON'T ARGUE ABOUT FLASH YOU LITTLE SKANK NO ONE BREAKS THE META BECAUSE HEIMERDINGER IS SO META RIGHT NOW. But seriously flash is brokennnnn and Heimerdinger needs escape fast when he gets attacked, and ghost doesn't help that much because it helps by a base percentage, and Heimerdinger's base movement speed is godly slow
Smite: You need it on junglers, even though with Heimerdinger you can clear without smite, it helps secure objectives for your team, buffs, etc.

Alternatives
Clairvoyance: Some people are addicted to this spell, and if you use it right it's okay.

Another one you could take is 9/21/0. Don't take utility, it makes Heimerdinger too squishy as your 9 or 21.

Obvious why the current runes are chosen.
You could choose:
Quint of Movement Speed to help Heimerdinger's **** movement speed.
Glyph of Ability Power to give Heimerdinger more damage, but I think it makes him too suspectible to damage because you don't have MR
Seal of Armor is essential, no alternatives.
Mark of Magic Penetration is most effective.

No, these blue build items aren't just randomly chosen. I actually put a build together, then realized it was completely blue!

Starting Items

Hunter's Machete + 5 Health Potions isn't essential on jungle Heimerdinger, because he can get through the jungle first clear without any damage if he tanks turret right when its about to die, so you can do Boots of Speed + 4 Pots as Heimerdinger to help his **** movement speed.

Rush/Optional

Rush spirit stone, and boots of speed preferably first recall. Then If you want more sustainability in the jungle, feel like all your spells are worth it, Tear of the Goddess is good. Consider getting if your mid-laner is a blue-dependent champion.

Core

You need these items, as they give you a perfect balance between damage and survivability, which Heimerdinger desperatly needs. They are all also blue!

After Core

Liandry's Torment gives you some more damage if you have a lot of spare money, it is blue, and then void staff gives you magic penetration if they are stacking magic resist against you.

Get your turrets to rank 3 so you can have 2 asap, then level up your rockets because they are your main source of poke and damage. your concussion grenade is honestly only okay because of the stun, but its unreliable at best so max it last, but level it early to gank

You need the cooldown reduction for your turrets for camps, but if you are ganking a lot and going against champions then you should get Sorcerer's shoes