The Chevrolet Astro was introduced in 1985 to compete with the growing minivan market in the U.S. Although it was referred to as a minivan, the Astro was bigger than the minivans of today, though smaller than a full-size van. One advantage of this rear-wheel-drive, mid-sized van was it could tow up to 1,500 pounds more than its front-wheel-drive competitors, and the box-shaped design made it good for use as a cargo van for businesses trying to save on the cost of a full-size van. In 1999, the Astro came standard with a 4.3-liter engine.
Move both front seats all the way back. Remove the two nuts at the bottom on both sides of the instrument panel extension -- which is on the engine cover -- with a 13 mm socket. Remove the two screw covers at the top of the extension with a small screwdriver. Remove the other two screws with a T30 torx-bit socket. Pull the extension back until you have enough room to disconnect the two wire connectors, and then set the extension aside.
Pull down gently on the heater duct and remove it. Remove the two bolts at the bottom of the engine cover with a 13 mm socket. Loosen the two slotted bolts at the top of the cover with a long screwdriver. Pull back on the engine cover and lift it up and out of the Astro.
Locate the distributor, which will be at the back of the engine, so basically right in front of you with the engine cover off. You will see the wire connector for the camshaft sensor sticking out of the back of the distributor. Remove the two screws from the distributor cap with a T20 torx bit socket. Pull the cap up and move it out of the way without disconnecting the plug wires. Remove the two screws from the rotor with a T15 torx bit socket, and remove the rotor. You will see the cam sensor screwed to the inside of the distributor.
Disconnect the wire connector from the camshaft sensor. Tap the key until the slot in the reluctor ring is aligned with the cam sensor. Remove the two screws from the sensor with a T15 torx bit socket. Guide the sensor out between the slot and distributor. Guide the replacement cam sensor in and tighten the screws to 19 inch-pounds with a torque wrench. Connect the wire connector.
Install the rotor and tighten the screws to 17 inch-pounds. Install the distributor cap and tighten the screws to 21 inch-pounds. Install the engine cover. Tighten the slotted bolts on the top to 35 inch-pounds and the bolts on the bottom to 18 foot-pounds. Install the heater duct. Put the instrument panel extension in place and connect the wire connectors. Install the extension and snug -- but don't over-tighten -- the fasteners. Install the screw covers.
