Pre-Season S2000 Maintenance

Proper fluid maintenance is crucial to ensure healthy vehicle performance. On a car like the S2000, this is especially true. The AP1 S2000 has a 9,000 RPM redline, which is pretty much unheard of in a standard production vehicle. But when the engine spins at such a high rate, proper oil characteristics and weight can make a tremendous difference; affecting things like engine wear and oil consumption.

Car currently sits at 80,109 miles.

Engine Oil

The AP1 is notorious for oil consumption during VTEC range, especially during performance driving. I plan to do a trackday each year, along with a few autocross events as I can find the time. With that being said, I wanted an oil that had high Zinc and Phosphorous content (ZDDP) along with a higher 100C viscosity and HTHS. I’ve always been a fan of Amsoil products, and I consider their ZROD to be one of the best non-racing specific oils on the market. It’s also nice that I have a distribution facility nearby so I can get it easily.

Tech Data


Zinc Dialkyldithiophophate (ZDDP) is an anti-wear additive used widely for older engines that have flat-tappet cams. I wanted to use a high ZDDP oil because I feel that it’s a great choice for an engine that see such high rpm’s. You can see in the above oil analysis that Amsoil ZROD contains a substantial amount of Zinc and Phosphorous.


When choosing engine oil, it’s important to choose one that will be able to perform across a wide range of temperatures, while still meeting the specification of the auto manufacturer. Typically higher viscosity oils are going to have a greater film strength, thus providing greater protection at high temperatures.


High Temperature High Shear. This is another notable factor when evaluating performance oils. It’s basically the absolute viscosity at 150*C. The higher the number, the better the shear strength. From what I’ve found, 3.5 tends to be pretty good across most mid-range performance oils. Higher than that is even better, but you’ll likely start getting into heavier weights and more race-specific oils.Changing the oil on the S2000 is extremely straightforward and requires only basic tools.

  • 5qt Engine Oil, in my case 10W30 Amsoil ZROD
  • 17mm socket
  • Wrench
  • Torque Wrench
  • OEM 14mm Crush Washer for Drain Plug (94109-14000)
  • Genuine Honda Oil Filter (15400-PCX-004)

The steps are very straightforward, and should be similar for most vehicles.

  • Place oil pan beneath the car, and orient it so that you catch fluid from both the drain plug and the oil filter
  • Remove the 17mm oil drain bolt from the underside of the engine
  • Let drain for 20 or more minutes
  • Replace the old crush washer with a new one
  • Reinstall the drain plug onto the oil pan and fasten to spec 29ft-lb
  • Pre-fill the new oil filter with about .3qt of oil. This takes a few minutes since the new oil needs to fully absorb into the filter. So you’ll need to fill, let settle for a few seconds, repeat. Until you’ve got it to the point where the oil fills the filter about halfway.
  • Dip your finger into some of the new oil slightly and lightly oil up the rubber gasket on the new filter.
  • Wipe the filter surface on the engine to make sure it’s clean of old oil drippings. This is also a good time to wipe up any additional oil residue or spillage from the drain process
  • Working from the top-down, slowly lower the oil filter into the engine compartment and hand tighten (about 7/8 turn once the rubber gasket makes contact)
  • Fill the engine with about 4.5qt, then begin to check your oil level on the dipstick.
  • The middle of the dipstick is technically where you’re aiming for. The “L” marking is .5qt Low, the “H” marking is .5qt High.
  • For this fill, I filled to the H marking since this is the first time I’m changing the oil since I got the car and I want to be able to easily observe whether I’m getting any consumption. About 5.2qt
  • Replace the fill cap, and start the car. Let it run for about 5-10 minutes until it’s fully warmer up.
  • Check for leaks.
  • If all looks good, you’re done!

Upon inspection as I was draining the oil, I found that the Timing Chain Tensioner (TCT) appeared to be leaking from around the seals. I ordered up some new deals and replaced the oil to eliminate the leak. Writeup can be found here.

Transmission Fluid

For transmission fluid, I chose to go with what many consider to be a “miracle fluid” of sorts. While it’s not cheap, about $22/qt on Amazon, I have high hopes for this fluid and don’t anticipate having to change it out for a couple of years. I considered first flushing in some cheaper fluid for about 6 months to work the old stuff out, but instead just bought an extra quart of the good stuff and will just do a second quick flush.

  • 2 qt manual transmission fluid of your choice that matches OEM spec.
  • Hand pump for the fluid
  • New OEM crush washers
  • The drain bolt is just a 1/2″ square drive, and the fill bolt (to the left of the sensor in the pic) is a 17mm socket

Drain all of the old transmission fluid completely by removing the drain and fill bolts. I let mine drain overnight to try and get as much out as I can. But also because I didn’t have time to finish the job right away.

Reinstall the drain bolt with a new crush washer, and torque to spec 29lb-ft.

Using the hand pump, you should be able to fill with about 1.8qt of fluid. The fluid should be slowly dripping from the fill hole when it’s full. Or you can also slip your finger in, and you should be able to feel the fluid right up to the bottom edge of the fill hole.

Fill bolt torque spec is 33ft-lb.

Rear Differential Fluid

After some debate between whether to use 75w110 or 75w140, I decided to just go with the 140 due to the higher demands of track and autocross. I am not sure whether 140 is absolutely necessary, but it really doesn’t hurt anything to go with the thicker fluid and will make it less likely to break the diff in track events. I did some research as to why so many s2000 track drivers recommend w140 fluid, and found an interesting article by Torsen. They actually say that pretty much any fluid will Work with their differential, however theoretically the heavier weight the fluid, the less friction and thus there could be very very slightly measurable reduction in locking action. Article can be found here. For the record, Honda states to use an SAE90 equivalent. For regular use, a w110 will best meet this specification. The w140 Fluid will have a higher film strength and shouldn’t sheer down as quickly. However, if you are unsure when choosing fluid you should always consult the owners manual.

The Severe Gear Fluid that I chose to go with has additives specific to helping prevent drivetrain shock, and operating in high pressure environments.

  • 1qt of gear oil. I chose to go with Amsoil Severe Gear 75w140
  • 24mm drain bolt socket, and a 23mm hand wrench
  • New OEM crush washers for both the fill and drain plugs
  • Hand pump

The only hiccup that I hit was that I didn’t have a 23mm box wrench to reach the fill plug. So I had to run out to Autozone and pick one up for like $13.

The diff takes right around .8qt of Fluid, and you should notice a slow drip as you fill it up to the proper amount.

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