There is 1 on each side of the block, they will be in the center just above the oil pan where it bolts to the block. It takes a 1/2 inch 6 point socket to remove them.
Most all engines have block drains for coolant. If they are reasonably accessible or not is the probelm.
Every block has one (L4 or L6) or two (V6 or V8) coolant drains. Not always easy to access.
Take it to dealer and hope they do it correctly, There is a plug on bottom of radiator loosen and it drains coolant out of radiator, but not out of engine, There are plugs on the side of the engine block that have to be removed to drain coolant out of block. Probably impossible to get to and accidents happen, sorry I hope this helps some.
There are block coolant drains on both sides of the block. Drivers side block drain is towards the front and the passenger side is towards the rear. They take a large allen wrench to unscrew.
It depends on what year you have. Some are in the back of the head and others are in the block where the block coolant drains are located. Some have one knock sensor and others have two.
To drain your coolant there should be a petcock ( metal rectangular screw type drain)or plug on the bottom of your radiator ussually near the left or right side of radiator.
NV3500 for small block, NV4500 for big block.
I think they do
bottom corner of raditator
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No, you typically do not need to pull the radiator on a 1991 GMC Z71 to change the drain plug. The drain plug is usually located on the engine block, and you can access it without removing the radiator. However, ensure you have enough clearance and consider draining some coolant beforehand to avoid spills.
A 350 is a small block, Not a big block. And you can buy that engine new from GM. for about $2000.00