Tune Up

Giving your RX-7 a tuneup is always a good idea on a brand-new car, and should be part of routine maintenance throughout the car's life. And, it's always a good idea to give the engine a once-over whenever you do an oil change or happen to be under the hood to check for potential failure spots.

The following is a list of consumables to change/replace, and the recommended service interval. This is all based on my experience - this isn't necessarily the last word on what to use and the service intervals. Everything recommended here I've used myself and have had great success with. But, as usual, if you break your car, I'm not to be held liable!

 

Oil

Every 3,000 miles

Oil is VERY important to a rotary engine. Not only does it lubricate the motor internals, it's injected into the combustion chamber to lubricate the apex seals, and also helps transfer some of the heat away from the motor.

Recommended Oil - I use Castrol GTX. It's a good oil, it's dirt cheap, and you can buy it literally anywhere - I've seen quarts at a small mom n' pop grocery store in the middle of nowhere. Some people like Havoline as well. I recommend 20w50 in the summer, and 10w30 in the winter, or 10w30 all year if you live in a cooler climate. Synthetics can be used in a rotary, but it's generally not recommended. It's much wiser to use a good grade regular oil, change it often, and take the money you save to buy more parts for the car :).

Recommended Filter - Purolator PureOne. Again, it's inexpensive and priced well - about $5 from Pep Boys. And, it's easy to get one. This filter uses a more advanced higher density filter to trap more foreign particles. For more inexpensive filters, the plain white Purolator filter does great. Avoid Fram filters - they're proven to be made horribly cheap. Many people swear by the stock Mazda filter - I think it's a lot of bunk. I think you can find much better filters on the aftermarket, for a lot less money. For more info on oil filters, see Steve Cirian's site for a great oil filter comparison.

 

Coolant

Every Year

Rotaries are prone to coolant passage corrosion - I have taken apart a number of motors with yellow-orange passages and rusty corrosion inside. This typically is from too much water in the coolant or neglecting to change the coolant. I bought my car from the original owner, who meticulously changed the oil and coolant. All the coolant passages, when I rebuilt the motor, were spotless, shiny metal. It really pays off.

I recommend Prestone antifreeeze. I run about a 50/50 mix of antifreeze to water - the antifreeze has the anti-corrosion properties. I usually run some Redline WaterWetter as well - it can dramatically lower water temperatures.

When you change the coolant, remove the drain plug on the radiator and the block drain plug. The block drain is on the driver's side of the motor just above the motor mount. There are 3 bolts holding the motor mount on, and the "4th bolt" is the drain plug. It's a 14mm plug - just unscrew it. This will empty almost all of the coolant out of the system. Replace the two plugs and refill. It will take some time to get all of the air out of the system - you can squeeze the lower radiator hose to pump some of the water through the system. Once you get the system full, start the car, and let it come up to operating temperature. Let the car cool completely off, then double-check that the system is topped off and the overflow tank is at the "full" mark.

 

Thermostat

Every 30,000 miles

This is VERY critical to the proper operation of the engine. An overheated rotary is a pile of junk parts - don't let it happen to you! I would change the thermostat as a matter of course - relatively easy to do while you're doing a yearly change of the coolant.

The ONLY thermostat to get is the stock Mazda thermostat, period. I have yet to find one that works as well. It's typically about $15-20 at the Mazda dealer, and they almost always have them in stock. Parts store thermostats only last a few *months* - they're not worth it!

When installing the new thermostat, put some anti-sieze on the bolts holding the water neck to the water pump housing. I have seen these fasteners break off, sieze in place, etc. causing a lot of work for a simple job - some antisieze is VERY cheap preventative maintenance. The stock thermostat comes with a new gasket - there's a paper gasket for the '86-88 cars and a rubber o-ring that goes around the thermostat for the 89-91 cars.

 

Fuel Filter

Every 30,000 miles

I believe the change interval is higher in the owner's manual, but, after seeing a motor let go after a lean condition caused by a clogged fuel filter, I feel it's important to do so. Again, I use the Purolator fuel filter. K&N also makes a good fuel filter, but it's pricey, and I haven't tried it yet :).

To change the filter, you have to depressurize the fuel system. Start the car, and let it run at idle. Look under the dash - on the inboard side of the steering column is a yellow relay with a 6-wire plug going to it. Unplug it. This is a fuel pump relay, and the fuel pump will shut off, and the engine will stall shortly thereafter. Then, open the gas cap to let out any gas tank pressure, then reinstall the cap. The filter is on the driver's side of the car, down low on the firewall. It's a bit of work to get the hose clamps and hoses off of the filter. Make SURE there's no open flame or lit cigarettes around - some gas will leak out, and it's highly flammable!

 

Spark Plugs

Every 10,000 miles

Due to the nature of the long combustion chamber of the rotary, the RX-7 needs a really hot spark to run well. Also, the plugs have to be designed for the heat of the rotary's combustion chamber.

The *only* plug to run is the NGK. The part numbers are NGK BUR7EQ and BUR9EQ. The 7 plug is the leading (lower) plug, and the 9 plug is the trailing (top) plug. For modified TurboII cars, you can run all 9's for all of the plugs.

There are also the platinum version of these plugs - the part number has a "P" at the end. These are stock on the 3rd generation RX-7, and really offer no benefit except longer plug life.

Do NOT use any other spark plugs. There are some that are specified for the rotary (I think the AutoLites) but the car will NOT run correctly with them. Also, the wrong plug can cause engine damage and failure - it's just not worth it!

During installation, do one plug at a time to make sure you keep the plug wires straight as to which goes where. Always use anti-seize on the threads of the spark plug - the rotor housing is aluminum, and the plug body is steel. The plugs can sieze into the rotor housing, making for very difficult and expensive repair - antisieze on the plugs will alleviate that problem.

 

Spark Plug Wires

Every 60,000 miles

The stock spark plug wires are relatively well-built to carry the powerful spark to the plugs. But, these should be replaced as a matter of course every 60,000 miles or if the wires show signs of failure.

The stock NGK wires are very good, and priced reasonably well - about $30-40. Magnecor also makes excellent wires that are very sturdy and durable - a bit of an upgrade over the stock wires, priced at about $60. Avoid cheap parts store wires - while they'll get you by, they won't last long and will fail on you when you don't want them to! Jacobs wires perform well, but in my opinion don't fit well at all, making spark plug changes a chore.

 

Manual transmission gear oil

Every 40,000 miles

This is very often a neglected service. I've seen transmissions that have NEVER had the gear oil changed, and this is a 100,000 mile car! Fortunately, Mazda designed the gearbox relatively well, but this is very hard on the transmission going this far!

I have used Redline synthetic gear oil with excellent results. Redline MT90 is the correct oil for the tranny - 3 quarts. Mobil 1, Royal Purple - there are a number of great oils out there. Make SURE to use a synthetic - plain gear oil just doesn't cut it. 75w90 is the weight of the gear oil. If you had standard gear oil in the transmission, and change to a synthetic, I guarantee you'll notice a difference in how smooth the tranny shifts - it's dramatic!

The non-turbo cars have one large drain plug, with a fill plug on the driver's side of the tranny. The turbos have 2 drain plugs - one big one on the bottom, and one on the side, along with 2 fill holes in the side. Use a gear oil pump to fill the tranny - pump in the oil until the oil starts trickling out of the fill hole.