Changing a Thermostat in 1995 Mazda MX-6

In 1988, Mazda changed the name of the two-door body style of its popular 626 model to the MX-6. The 1995 MX-6 came standard with a 118-horsepower, 2.0-liter engine, which used a mixture of ethylene-glycol-based coolant green and water to keep it cool. A thermostat regulated the flow of this coolant mixture by opening and closing at precise temperature ranges. When the thermostat fails to open or close at these specified ranges, your 1995 MX-6 may experience overheating or overcooling. Both symptoms may cause serious damage to your vehicles engine, so you must change that failed thermostat immediately to avoid more costly repairs in the future.

Instructions

Removal

1

Lift the front of the MX-6 off the ground with a floor jack and slide jack stands under the vehicles subframe. Lower the MX-6 onto the jack stands.

2

Crawl under the front of the car until you have a clear view of the lower, passengers side of the radiator. Find the radiator petcock, the valve with a plastic thumbscrew, located on the lower, passengers side of the radiator.

3

Unscrew the coolant filler cap, which is behind the engine, on the passengers side. Position a drain pan directly under the petcock and turn the petcocks thumbscrew counterclockwise to start the flow of coolant from the radiator. Once the flow of coolant from the radiator stops, tighten the petcocks thumbscrew.

4

Raise the MX-6 off the jack stands and lower it to the ground.

5

Trace the upper radiator hose toward the engine until you reach the metal thermostat housing, which connects the hose to the engine. Slide the clamp on the end of the hose about 3 inches toward the center of the hose, using slip-joint pliers. Pull the hose from the housing with a slight twisting motion.

6

Remove the bolts securing the thermostat housing to the heater inlet assembly using a ratchet and socket. Pull the thermostat housing from the water inlet assembly, exposing the thermostat. Pull the thermostat from the water inlet assembly.

7

Clean the mating surface on the thermostat housing and water inlet assembly with a plastic scraper and clean, lint-free cloth.

Installation

8

Install the new gasket, which comes with the new thermostat, around the perimeter edge of the new thermostat, if it is not pre-installed. Rotate the gasket until the small tab protruding from it aligns with the jiggle valve in the thermostat, if needed.

9

Guide the thermostat into the engine, spring side first, aligning the tab protruding from the thermostat gasket with the cutout in the thermostat housing.

10

Reinstall the thermostat housing and hand-tighten its retaining bolts. Tighten the thermostat housing bolts to between 14 and 18 foot-pounds using a torque wrench and socket. Press the upper radiator hose back onto its inlet on the thermostat housing and slide the hose clamp to within a half-inch of the end of the hose using slip-joint pliers.

Filling and Bleeding the Cooling System

11

Open the radiator cap and pour 50-50 premixed ethylene-glycol coolant into the radiator filler neck at a rate of about one quart per minute until the coolant level reaches the base of the filler port the port on the behind the passengers side of the engine.

12

Open the coolant reservoir and pour 50-50 premixed coolant into the reservoir until the level reaches the F mark. Close the coolant reservoirs cap. Tighten the filler cap onto the filler port and the radiator cap onto the radiator filler neck.

13

Start the MX-6s engine and allow it to idle until it reaches operating temperature, which is roughly halfway up the temperature gauge. Keep a close eye on the engine temperature and shut the engine off if the gauge nears the Hot reading, then allow the engine to cool and repeat steps 1 through 3.

14

Increase the engine speed to between 2,200 and 2,800 rpm and hold it there for five minutes.

15

Shut the engine off and allow the vehicle to sit until the engine is cool to the touch, then unscrew the coolant filler cap.

16

Repeat steps 1 through 5, then verify that the coolant level is at or slightly below the base of the filler neck on the filler port. If the coolant level is low, repeat the entire bleeding and refilling process from Step 1.

17

Add coolant to the coolant reservoir until the level reaches the F mark, if needed. The 1995 MX-6s cooling system has a total capacity of 1.85 gallons, but the exact amount needed to refill your MX-6s system may vary.

18

Take the old coolant to a used automotive fluid recycling center. Some auto parts stores take old coolant free of charge.