Well You Bought Your First RX-7

January 23, 2026

Congratulations~! You're in for a whole new world of joy, pain and all the feelings in between.

Let's just assume that your still working on your general knowledge base on owning a old car. What should you do first? What are some common failing parts? What are some hyper-critical parts that you should replace ASAP? Lets try to touch up on all those things as best as we can.

Lets start generally and then get into model specifics~!

What do I do first?

well you should get insurance and register it..... I'm just going to assume that you got a relatively well running car. We will touch on getting your non starting car running in other blog posts.

My buddy Mr.V thinks you should compression check any new car you get. It's not a bad idea, but I rather would not know if the engine is lower compression if it's running fine. I generally only check compression if I'm having hot start issues or the engine is running badly.

It's always good to do the basic safety inspections on a car that people end up skipping over.

Think:

Tire Pressure
Tire tread and date of mfg
Brake sound/performance
Wheel Torque
Lights
- Especially Brake lights (you dont want to get pulled over immediately after buying a new car)

What should I replace first?

well the first items are general maintenance items. I know, I know, you want to install your fancy drifty coil overs and side skirts. This is more important.

Spark Plugs (Use NGK OEM Equivalent)
- Wires
Thermostat
- Make sure to use OEM!!!!!!
Coolant replacement (maybe flush)
Water Pump
Oil & filter

I know this seems really basic but let me explain.

Rotaries eat through spark plugs, most likely the car you buy is due to have them replaced. Better idling, gas mileage, even possibly more power.

Rotaries run Hot. This means that your coolant maintenance is especially critical. Factory thermostats tend to be of higher quality and historically fail less. Its a critical part, spend the extra 10-20$ on it.

Coolant replacement or flush. Like above it's probably due for one. But another thing to keep in mind is that if the coolant additives are incorrect or non-existing (garden hose water) it can corrode the Irons on the block. This means coolant seal going bad and a engine rebuild.

Oil is super critical. Something like 20-30% of engine heat is also transferred through the oil system as well. Most likely is it also low since the engine is designed to inject oil into the combustion chamber for the apex seal lubrication. It's cheap, just do it.

Next round of replacements (2~3 Months)

I would say once you finish up the list above, you can start putting your GT wing on your car without the old Rotards cringing at you.

This next list of items I would try to get done fairly quickly (2-3 months) but I wouldn't worry about it too much.

Differential Fluid
Transmission Fluid
Brake Flush
Radiator (If original)
Radiator pressurized cap
Radiator Hoses & Heater Hoses
Belts
Fuel Filter

Man, its amazing how much quieter the drivetrain gets when you replace the fluids. It makes a massive difference on drivetrain efficiency and noise.

Brake flush, cause every car on the road is probably due for one (including mine). You don't want your 15 year old brake fluid to start boiling on the Touge on your first outing. Yes, we all know your going to try to drive too fast.

Longer Term Replacement Items:

Oil injectors/OMP lines
- Rebuild OMP if FB or S4
New/Rebuilt Injectors
- w/O-rings
Stainless Oil Cooler lines

If you want to keep the stock oil injection system, its highly recommended to replace the oil injectors as well as the OMP lines. It will keep the engine happier, longer.

I haven't seen too many fuel injectors outright fail. They just leak, get plugged up or just don't match each other. You got 2 compression chambers, and they need the same amount of fuel. Its very critical that they have the same volume of fuel being distributed by the injectors.

Hypercritical Items:

Now we are getting towards to specifics. If you have records of these items replaced by the last owner (in a reasonable time) then you can hold off. If not, replace immediately to avoid sad days.

Fuel Pulsation Dampener (FD3S & S4)
- The fuel pulsation dampener is know to leak when it gets old. When it starts leaking, your car can and most likely will catch on fire. It will be totaled and you will cry.
Vacuum Lines (All Gens)
- I wouldn't recommend replacing vacuum lines on a FD that runs perfectly, its a major hassle. But on FCs and SA/FB its much less complicated and will reduce the chance of vacuum leaks in the future. Vacuum leaks can cause lean conditions which can cause pre-detonation and engine failures.
Plastic Filler Cap Neck/Thermostat Housing (S5)
- These melt after many years