The answer was provided with this. The new VQ engines dont need this due to updated coolant system, This was mainly with problematic DE's possible some info has copied over like visual diags.

A spill free funnel and if you want to bleed anything, the overflow plastic bleeder on the drivers side of the radiator.

If you work on your own cars and own an Infiniti and dont have a spill free funnel, you should.

 

I know this thread is 11 years old but maybe this will help someone. The air relief plug, at least on my '13 xS, is on the top driver side corner of the radiator on the back side. You have to remove the air filter box to get to it.

 

To update this thread. The bleeder can exist in both hoses as shown in many variances of 3.7s. Many times the wanting of the most accurate info will trigger some OCD with some anxiety into thinking you're about to damage the cooling system.

For many VQs the location of bleeders change and many times it will subject you to this and if bleeder location was as detrimentally specific as some might think then you would not see non oem replacements as a single piece hose or no bleeder at all. The lack of a bleeder will not ruin your vehicle nor cooling system though it will make the cooling burping a longer process to "air out"

I choose to not drip any coolant in the back part of the engine as anything quality will not evaporate, it will dry up/evaporate some while leaving residue right on top of each exhaust manifold depending on the location of your bleeder. I use a $20 universal coolant funnel. (A must have tool for any car just like an OBD scanner)

Please note that in many cars that these engines are swapped in dont include this heater bleeder and life continues for these folks. In all reality an improper bleed system that uses a bleeder will always keep air trapped in the top portion of the bleeder bolt/screw so it's important that without a funnel you try your absolute best.

Even then it's difficult to bleed these cars cold without a funnel, so many start the engine and this causes water/coolant to warm up which expands. By the time it cools down it will have condensed a bit causing now lower coolant levels which is why many folks struggle with this process.

Fix your bleeders and buy a funnel so you can see how you barely use the bleeders after maybe a few seconds. The heater core is straight through and doesnt have a valve which means it will always see heavy flow. Even getting a full stream of water/coolant coming out doesnt mean your coolant system is bleed. If you have a funnel you will see how air bubbles continue to come out after the bleeding which begs to ask the question if you intend to use a funnel, was the bleeder necessary to begin with.