Where is the engine block heater plug-in on 2008 Navigator

Freeze plugs, also known as expansion plugs or engine block heaters, are designed to expand and contract along with the engine block as it heats up and cools down. They are located in the engine block and are used to prevent the engine block from cracking due to the expansion and contraction of the metal.
In a 2008 Chevrolet Silverado 2500HD with a 6.0L engine, the freeze plugs are located in the following locations:

• Two freeze plugs are located on the back side of the engine block, near the top.
• Two freeze plugs are located on the bottom side of the engine block, near the front.
• Two freeze plugs are located on the passenger side of the engine block, near the bottom.

Here is a diagram showing the locations of the freeze plugs in a 6.0L engine:
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I hope this helps! Let me know if you have any other questions.

block heaters are aftermarket so there isn't a specific location for that vehicle, However i can tell you that they are usually located in a freeze plug hole in the side of the block. if you look at your engine block just above your oil pan you will see several circular plugs, one of the plugs will have two prongs sticking out of it, and that will be where your plug connects. good luck.

If you have the heater check for it in front of radiator coiled up on passenger side near bumper just under it

This was a factory option. Not all had it.

Block heaters are installed on the engine block in one of the "freeze plug" openings. The freeze plug is punched out and the block heater is installed in its place. The freeze plugs, about 3 on each side of the engine, are midway up the block- a round, slightly recessed metal plug about 2 inches in diameter that is driven into these holes made during the engine casting process. The freeze plugs will be found below where the exhaust manifold attaches-so if you are looking on the side of the engine with the exhaust manifold-look behind and just below the exhaust manifold. The other side of engine will have the same number of freeze plugs at the same level on the engine block.
Your block heater is probably on the front facing side of the engine (towards the radiator). It is probably shinier than tom the he regular freeze plugs, will have a small screw in the center for tightening when installed, and will have 2 or 3 metal prongs that your heater cord attaches to. Simply plug it back into the heater. Just remember: about halfway up on the engine block, from the oil pan rail at bottom to the top of block where the cylinder head mates.

Block heater should be under exhaust manifold on passenger side of vehicle in place of one of the frost plugs. trace the wire coming out of this to find the plug if in fact you do have a block heater. It may be an option on your truck.

If your truck came equipped with a block heater the cord should be routed to the front bumper or just inside the engine compartment as you open the hood.Sometimes it is tucked into the back of the front bumper,or around the lower left corner of the inner wheel well were it meets the core support at the lower corner of the radiator.If you can not find the cord crawl underneath the truck and look at the "freeze plugs" in the side of the block,they are just round plugs about 2" or so across and are pressed into the side of the block this is where the block heater is installed by removing one of these plugs.So just look for one that has a cord to it or has an electrical connection to it with out a cord I have seen several vehicles equipped with a block heater and the cord has simply fallen off.Hope this helps sorry so wordy good luck.

Since your blower is working and it is a heat issue,thats where we'll start,First thing is have you checked the coolant level in the radiator when engine is cold,make sure it is filled to top,next verify you have coolant in reserve ,Start your van and get it up to normal operation temperature,If your heat gauge on the dash works correctly it should be 190 degrees,Now lift the hood and locate the two heater hoses going into the heater assembly at the fire wall,Both hoses should be hot to hold on to,if both are hot and no heat inside your problem will be the blend air door in heater assembly.
if neither hose is that hot you need to replace the thermostat in the engine to get it up to 195 degrees.
if one hose is hot and one is luke warm then the heater core is blocked and to blame. hope this helps you.

it should be in front near the grill, was there a block heater installed on this van? if you look at the engine were the freeze plugs go ,if a heater was installed you should see the element in one of the freeze plug holes instead of a freeze plug, if there is one then follow the cord, hope this is helpful, good luck.

You are under warranty. Use the Customer Service Phone# and question why this is not fixed.

It sounds like it can be alternator or body grounded antenna problem. You should also check and see if the problem starts with the heater coming on.

The heater would start after the car heats up(10 minutes) or the Alternator would have finished charging and switched into idle mode( about 10 minutes).