This is a major repair and requires a skilled mechanic. You have to take the head off.
and replace the gasket and get it put back on properly. Unfortunately, something made
the gasket blow and once you get the engine apart you will likely see that the
rings and pistons are worn and the valves need regrinding , etc, etc.
I do not know about the Astro Van, but you may have to take the engine. If so,
this is a major job , requiring some kind of hoist, in itself, as is putting it back in.
You might do better by selling the car for parts.
figuratively yes but unadvisable
The gasket is between the head and the manifold and simply remove the bolts and replace the gasket after cleaning it real good.
The most likely cause is a blown head gasket.
Possibilities are low coolant, defective radiator, leaky hoses, blown head gasket...
You either have a bad manifold gasket or blown head gasket.
Symptoms will be: Loss of coolant with no apparent leak. Overheating. White smoke from the exhaust. Oil level over full. Foamy substance on the underside of oil cap, & dipstick. Air bubbles escaping from radiator with engine running cap off. Miss on one or more cylinders. If you do have a blown head gasket, STOP running the engine immediately as serious engine damage will occur. Replace both gaskets not just the one that is blown.
Replacing the head gasket on any vehicle is a long and complicated process, however if you wish to see basic step-by-step instructions go to the related question on the right side of the page "How do you replace a head gasket?"
A seized gear can cause a knocking sound on a 1987 Nissan 5 speed transmission. A blown gasket can also cause this sound.
To replace the oil pan gasket in a 1987 Isuzu Trooper 2.3-liter, first, drain the engine oil and remove the oil pan by unscrewing the bolts that secure it. Clean the surfaces of the oil pan and the engine block to remove any old gasket material and debris. Place the new gasket in position, apply a thin layer of gasket sealer if recommended, and reattach the oil pan, ensuring all bolts are tightened to the manufacturer's specifications. Finally, refill the engine with oil and check for leaks.
To repair the head gasket on a 1987 Ford Bronco, the head and the old gasket must be removed. Purchase a new head gasket and carefully install it according to manufacturer specifications.
700R4 transmission.
To replace the head gasket on a 1987 Mercury XR7, first, disconnect the battery and drain the engine coolant. Remove the intake and exhaust manifolds, then detach the cylinder head by loosening the head bolts in the specified sequence. Clean the surfaces thoroughly, place the new gasket, and reassemble by reversing the disassembly steps, ensuring to torque the head bolts to the manufacturer’s specifications. Finally, refill the coolant, reconnect the battery, and check for leaks before starting the engine.