You're gonna have to remove what's left of the bolt. If it's broken off flush, you'll have to drill it out and use an extractor. If there's any sticking out, you may be able to use vise grips.
You will notice water leaking out of the water pump specifically around the pulley area.
the heater core in the heater unit may not have air going through it, or the hoses for the water to pass through the heater core may be broken. Or the flaps controlling the airflow may not be working correctly
you must first remove muffler bearing
Most usually at the front of the engine, on top and can recognize it by the connecting water hose, usually larger.
There is a separate belt on the opposite side of the motor from the serpentine belt. that belt runs off the camshaft and drives the water pump
it is at the driver's side end of the frontmost camshaft right up on top. it is an easy fix but you will need the special tool.
remove top water hose remove four screws frist remove belt from tension spring then need special wrench to turn and pull water pump out
In a housing that attaches to the water pump at the rear of the engine. Follow the top radiator hose down to the water outlet on the engine. The stat is in the water outlet. AT THE END OF THE UPPER RADIATOR HOSE ( ENGINE END)
it is on the drivers side of the engine compartment in the front of the motor when you start the motor you will see a small belt turnig and you will need a specail tool to get the water pump out
Hope this will help,of recent I relaced mine (88 eldorado) and found it to be rather easy. from front Facing engine, pump is located to the left, facing fender wall. Pump I found to be of weird shape, as in an oblong shape. With some 10-15 small bolts of attachment.(exact # donot recall).All gained acess by sockets or wrenches. Place caution not to strip bolt heads, and if I recall, some needed wd-40 and an overnite saturation. Good Luck
On the Northstar engine, the water pump is on the RIGHT side of the engine (looking at it from the front. If you look from the left (Drivers) side fender, it's right in front of you- You'll see the water pump drive belt running off the forward camshaft.
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