The 2.0-liter, inline four-cylinder engine came standard in your 1999 Mercury Mystique GS. The Mystique -- Mercury's equivalent of the Ford Contour -- was praised for its handling, but was never well-received by consumers. The car was too small to compete in its price range and lack of rear legroom was a common criticism. Though the 1999 model was a bit more spacious for rear-seat passengers, it was too little too late to save the Mystique in the eyes of the car-buying public.
Park the car on solid ground and set the parking brake. Chock the rear wheels. Open the hood and allow the engine to cool completely.
Find the engine heat shield on top of the engine. Remove the upper heat shield retainer bolt, using a ratchet and socket. Remove the upper heat shield retainer nut from its stud. Remove the coolant hose bracket and lifting lug mounting hardware, using a ratchet and socket. Pull the dipstick tube out of the engine. Remove the A/C hose mounting bracket hardware and lower shield bolts. Remove the shield from the engine compartment. Remove the four exhaust manifold-to-catalytic converter retainer nuts.
Locate the front jacking points just to the rear of the front wheel wells. Lift the front of the car and support it on jack stands at the secondary lifting points on the frame just inboard of the front jacking points. Locate the rear jacking points forward of the rear wheel wells. Lift the rear of the car and support it on jack stands.
Working beneath the car, remove the catalytic converter clip and mounting bolt, using a ratchet and socket. Remove the converter-to-exhaust pipe hardware, using a ratchet and socket. Unplug the O2 sensor electrical connector. Remove the converter from the rubber hangers and remove the converter support bracket hardware. Lower the converter assembly and set it aside.
Position a drain pan beneath the oil pan drain plug. Remove the plug, using a wrench, and allow the oil to drain from the engine. Install the drain plug and torque it to 17 foot-pounds, using a foot-pound torque wrench.
Remove the oil pan bolts. Insert a sharp spatula between the oil pan and engine to release the adhesive. Gently strike the oil pan on the drain plug with a rubber hammer to encourage it to release. Support the oil pan to prevent it from dropping suddenly upon release.
Scrape the old adhesive from the mating surfaces, using a gasket scraper. Remove all traces of oil from the mating surfaces with solvent and clean rags.
Install ten M6x20 studs into the blind holes in the bottom of the engine-to-oil pan mating surface. Apply a 3 mm bead of sealant centered 5 mm from the inside shoulder of the pan flange, all the way around the pan mating surface. Stay toward the inside of all of the pan bolt holes. Move the oil pan into position on the engine and install the oil pan bolts finger tight.
Assign the following numbers to each pan bolt, starting with the bolt at the drain plug and proceeding clockwise; 1, 3, 9, 11, 15, 13, 8, 6, 2, 4, 10, 14, 16, 12, 7, 5. Torque each bolt in numerical sequence in two stages -- first to 53 inch-pounds, then to 88 inch-pounds, using an inch-pound torque wrench and socket.
Move the converter into position. Slide the front onto the exhaust manifold studs, and the rear onto the exhaust pipe. Install the support bracket hardware and torque it to 18 foot-pounds. Plug in the O2 sensor electrical connector. Install the converter on its rubber hangers. Install the converter-to-tailpipe hardware and torque it to 30 foot-pounds. Install the converter clip and bolt, and torque it to 18 foot-pounds. Lower the Mystique to the ground. Install and torque the converter-to-exhaust manifold nuts to 30 foot-pounds.
Install the oil dipstick tube in the engine. Install the lifting lug and A/C line bracket hardware and torque the bracket to 88 inch-pounds. Install the upper shield bolt and nut, and torque them to 12 foot-pounds. Install the lower shield bolts and torque them to 15 foot-pounds. Clip the A/C hose into the bracket.
Add fresh motor oil to the engine. Start the engine and check for exhaust and oil leaks. Turn the engine off. Check and adjust the oil level as necessary.
