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How to remove, replace and tightenaccessory belts for a second

generation (NB, 1999-2005 ) MazdaMiata MX-5

If your Miata is squealing loudly either when you engage the air conditioner, turn onthe car, or just drive around you may have a loose/worn out belt. If it has been doingthis for a while then it is probably glazed (ruined). New belts are between $10-$20each. They are simple to replace (1 – 2 hours) even for the non-technical person.

Gather the tools and parts. You need :x� 10mm, 12mm, 14mm socketsx� 12mm, 14mm wrenchesx� Philips screwdriverx� Pliersx� Jack, jack stands and blocksx� Cardboardx� Brass brush (new BBQ brush works)x� New beltsx� A bathroom scale

Setup your car. Jack the front wheels and put them onstands. Cardboard on the jack can help prevent dents inthe metal. Make sure the parking break is on and thatyou block the rear wheels. Leaving the jack extended onone gives you added insurance.

Open your hood. To get at the beltsyou must remove the air duct justbehind your radiator. It is attached atthree points. Use your screwdriver toloosen the clamps on either end,then remove the middle clip withpliers. Wiggle the duct off eachconnection.

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The belt closest to the radiator goes from theengine to the air conditioner compressor thenthe power steering. Not all miatas have thisbelt depending on A/C on power steering. Thetension in this belt comes from the airconditioner compressor pulley. The tensioner(circled) needs to be adjusted to remove thebelt.

Three bolts are used to adjust this tensioner. Bolt 2is accessible through a gap in the power steeringpump pulley. It may be necessary to turn over theengine to line up the bolt with the gap. The car willnot run with the air duct out, but it should turn over.Loosen the bolts in the numbered order. Bolts 1 & 3are 12mm and bolt 2 is 14mm.

You may need to secure the nut on oppositeend of bolt 2. Use a 14mm wrench on the nutcircled (photo looking over the top of thetensioner into engine compartment).

Loosen bolt 3 to slowly drop the air conditioningcompressor down. A wrench is probably better soyou don’t get interference with the air intake usinga ratchet. If you just want to tighten this belt, thenskip down to page 5. Slip off the belt.

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The second belt goes from the engine to thewater pump pulley above then the alternator.The tension in this belt comes from thealternator compressor pulley. The tensioner(circled) needs to be adjusted to remove thebelt.

Again, three bolts are used to adjust this tensioner.Bolt 2 is access from under and behind thealternator. We need to remove the splash guardunder the car for access. Loosen bolt 1 using a12mm socket.

You can get away withjust removing thefasteners on thepassenger side of thesplash guard to accessbolt 2. There should be10mm bolts and Philipshead screws holding it up.The left photo showsabout where the bolts are(taken from below the carin front of the passengertire, looking up). On theright shows the location ofbolt 2 after the splashguard is moved (behindthe coolant line).

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Use a 14mm wrench to loosen bolt 2. Get up anddust yourself off. Loosen bolt 3 with a 12mmsocket to move the alternator. If you just want totighten this belt, then skip down to the next page.Slip off the belt.

Use the brass brush to scrub off the pulleys,especially if there is lots of gunk. Some peoplehave used brake pad cleaner if they are reallynasty. Brass is important because a steel brushcan possibly score the pulleys, which wear thebelts faster.

Wash your hands nowso that you don’t putany grease on yournew belts. Also, useyour bathroom scaleto get a feel for howmuch 22 lbs is withone finger.

Put the new belt on the alternatorloop. First wrap it around thewater pump pulley, then theengine pulley (the grove closest tothe engine) and lastly around thealternator. As you tighten bolt 3,check the tension on the belt withyour calibrated finger. The beltneed to be tightened so that 22lbs causes 1/3 inch deflection. Ifyou don’t trust your finger, thenyou can get a belt tension gaugelike the one to the right.

Tighten bolt 2 and then bolt 1. Reattach the splash guard under the car. Move ontothe next belt.

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Stretch the new air conditioning belt around theengine pulley (the groove closes to theradiator), then the power steering pump pulleyand finally around the air conditioningcompressor pulley. While the belt is loose,orient the power steering pulley so that bolt 2 isaccessible through the gap.

Tighten bolt 3 while checking the tension on the belt withyour finger. The belt should be tightened so that 22 lbscauses 1/3 inch deflection. Tighten bolt 2 then bolt 1.

Reattach the air duct. Lower the car. Turn it on. Hopefully all the squeaks are gone.

This crude diagram show you the routing ofthe belts. Belt 1 is in front of belt 2.

For those with model NA miatas, check out Rob’s guide on replacing the belts:http://www.miata.net/garage/KnowYourCar/S9_Belt.html