Water leak on manifold of 1996 susurban. looks like hydraulic line connected but suspect it might be rear heater hose that is leaking . any ideas?

Is you rotor a 4.6 if so Theres a bypass tube under the black nylon intake manifold it has a rubber hose on the end behind tell water pump you must remove the manifold to fix it

Yes, there are expansion plugs (freeze plugs) on both sides of the engine block and at the rear of the engine block between the engine and transmission. There are also a couple in the ends of the cylinder heads.

With all that said, I would like to add that many times with that engine, the heater tube and connecting hoses can leak and be mistaken for a rear expansion plug leaking. I would definately check this before pulling the transmission out.

There is a tube that runs from the back of the water pump under the intake manifold and out the rear of the engine where it hooks up to the heater hose/heater core. This tube has a small hose connecting it to the back of the water pump. There is also a hole in the back of the engine block that will allow antifreeze from under the intake manifold to leak into the transmission bell housing area. When this tube or hose leaks, it often gets mistaken for a leaking rear expansion plug.

It is very easy to check for this. Remove the serpentine belt and remove the alternator and look under the intake manifold down in the "valley" between the cylinder heads. If there is antifreeze in there, the hose or the tube is leaking. Look at the picture below. Item #3 is the tube and hose assembly I am talking about. Usually, just the hose is leaking. It should be replaced with a short piece of SILICONE heater hose. On some of the vehicles, there are 2 hose clamps. On others, the end of the hose that is attached to the tube has a crimped collar on it. If yours is like this, you can fix it by carefully cutting the crimp collar off and replacing the hose using band clamps. (screw-type)

Also look for antifreeze leaking into this area from the front intake manifold runner. They tend to leak on the front runner near where the thermostat housing is located. These will also leak into the valley area and run out the back of the engine. If the manifold is leaking, chances are it is warped. DORMAN makes a replacement intake manifold kit just for this purpose because it has been so common. It is also very easy to check for this with the alternator removed.
The DORMAN part number for your vehicle is 615-178 (See second picture below)

If it is antifreeze could be a head gasket, cracked head, leaking heater hose.
If it is water then your rain drainage around the wiper linkage is plugged up.
If it is washer fluid you have a break in the washer fluid line.
Someone who knows what he is looking for is going to have to put his hands and eyes on the car

These are common for cracking the manifold. Being that it is a 1996 the dealer isn't going to warranty it now matter how many miles are on it. Where is it leaking? Near the heater hose connection( passenger side on the rear) Or near the thermostat ( drivers side on the front near the alternator)?

gasket from-[intake manifold -water pump]also check the heater hose connection on the intake manifold has a tendency to leak

What kind of car?

Hello mrsfixit85: My name is Roger and I will be glad to help. If the leak is between the radiator and the front of the engine? I would suspect the water pump as the problem. But I would also look at the radiator tanks at either side of the radiator. They are known to crack and leak. Look at the radiator hoses. Make sure that they do not have a hole in them. If the leak is towards the rear or side of the engine I would look at the heater hoses. You did not say what engine was in your truck. But if you have a V-6 in your truck I would check the intake manifold area. Look at the fitting the heater hose connects to. This fitting is known to corrode off at the manifold. Also look at the corners of the intake to cylinder head. Should you see a sludgy trail from the corners in this area then the intake gasket needs replaced.
Should you need further help please just ask. Please rate the answer you received. This way I know it was helpful. Thank You for using Fix Ya. Roger

check to make shure that there isnt any cracks in the hoses or leaks in the radiator.

Check the connection at the left rear of the intake manifold. The thermostat is located in the front right, the connection to your heater core is in the left rear. The fitting is a pipe that is pressure fitted into the intake manifold. You should be able to check for a leak with a flashlght and an extended mirror. Look for a silver pipe about 1/2" in diameter. The leak will increase as you increase the RPMs.

Instead of removing the intake manifold and the the leaky manifold coolant hose, we simple place a 1" dia hose about 3" long with a **** down it so it can fit around the leaky coolant hose with two hose clamps and an agressive amount of "right stuff" silicone sealant and let stand for 24hrs which should fix the problem