Fluids for '96 Miata: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Jan. 2, 2011 8:10 p.m. ea_sport Reader

I am thinking about changing all the fluids on my new-to-me '96 Miata and I am a bit overwhelmed with all the information I learned from Miata.net so I figured I'd ask the Miata experts here. I understand that it's very subjective but I am just trying to see if I can find some consensus or common theme.

Some info about the car, it has around 135kmiles and the previous owner told me that the regularly changed the oil with Mobil1 10W-30 every 3kmiles, and just changed the transmission and differential fluids with RedLine about 1 year ago (not sure which RedLine product though). It wasn't driven much during his ownership and it seems to be well taken care of. I got most receipts from the first owner but not from the second owner (i.e. the guy I bought the car from) since he was out of the country when I bought the car (long story). As far as the use of the car, it will driven no more than 3 - 5 kmiles per year mainly week-end drives, autocross and maybe start to do driving school and HPDE.

Anyhow, here's what I thought:
- For engine oil: Mobil1, should I use 10W-30 or 5W-30 and should I use the High Mileage version of either one?
- Transmission oil: I heard a lot of good feedback on Miata.net on Motorcraft Full Synthetic Manual Transmission Fluid (part # XT-M5-QS). What do you guys think about this product? Have anybody here had any personal experience using this product over say RedLine MT90?
- Differential Fluid: It has Torsen and I am thinking about using Mobil1 75W-90 LS Synthetic Gear Lube. Should I use this over say RedLine 73W-90NS?
- Brake Fluid: ATE Super Blue.
- Do I need any specific coolant or any coolant (i.e. Peak) will do as long as it is changed every two to three year? I am asking because my old BMW was very particular about the type of coolant to use. Actually now that I mention it I remember that I still have more than a gallon of 50/50 mixture of BMW coolant and distilled water, can I use this on my Miata?
- How often do I need to change the power steering fluid and the clutch master cylinder and what should I use for these?
Am I missing anything? Since I am new to Miata world I am just trying to get as much information as possible without getting information overload ...thanks guys, again I understand that this topic is very subjective so I just want to learn from other people's experience.
Jan. 2, 2011 8:12 p.m. SpeedTheory Reader
1. Mobil 1 10w30.
2. Redline MTL for me.
3. Torsen rear end, Redline 75w90.
4. ATE Gold. Blue ended up "dying" the lines in my BMW, so every change afterwards would be very, very blue, even when ran Motul for years after.
5. No idea about P/S, but use the ATE for your clutch fluid as well.
Jan. 2, 2011 9:23 p.m. Woody SuperDork

I've had two '96s. I put Mobil 1 5W-30 in the engine, and Red Line in the transmission and rear diff. I think I used MTL in the transmission and 75W-90 in the diff.
Jan. 2, 2011 10:55 p.m. mehurricane None

ea_sport wrote: - Transmission oil: I heard a lot of good feedback on Miata.net on Motorcraft Full Synthetic Manual Transmission Fluid (part # XT-M5-QS). What do you guys think about this product? Have anybody here had any personal experience using this product over say RedLine MT90?

My tranny in my '95 was a bit crunchy in 3rd, I added the Motorcraft Tranny Fluid and it hasn't crunched since. I recommend it. No experience with the Redline in this car so I can't compare.

Another maintenance thing to watch is it is very common that the two rubber shifter gaskets are prone to tearing/wearing out. They also help with the shifter feel.

Hurricane

141 STS Miata (now wingless)
Jan. 2, 2011 10:57 p.m. Keith SuperDork

If it's got Redline in the trans and diff, leave it. It's the standard for a reason.

I'd stick with 10w30. Clutch fluid doesn't have to be anything special, use the leftover ATE if you have some, but any brake fluid will do the job. It doesn't have to deal with heat in a clutch.
Jan. 3, 2011 8:26 a.m. Slyp_Dawg Reader

I've got 10W30 Castrol Edge in the engine, planning to flush the trans and rear end with Redline, as soon as it comes in I'll be putting Prospeed RS683 brake fluid in with my stainless lines and maybe flush the clutch hydraulics if I've got enough spare fluid
Jan. 3, 2011 9:48 a.m. fastmiata Reader

Miata HLA's can be somewhat sensitive to oil viscositiy. 10W30 is about as low as you can go. Some engines prefer the old school 20W50. I do use synthetic fluids in all instances.
Jan. 3, 2011 12:33 p.m. Duke SuperDork

If I get some HLA tick after an autocross pass, what viscosity should I switch to?
Jan. 3, 2011 12:36 p.m. Keith SuperDork

Some like it lighter, some like it heavier although usually you want to go a bit heavier. Sometimes that's just the indication that you need new oil. Remember that the first number is cold viscosity, so going from 10w30 to 5w30 won't make a difference to a hot engine.
Jan. 3, 2011 4:11 p.m. Woody SuperDork

Keith, what's the best viscosity for a lifter that ticks on startup?
Jan. 3, 2011 4:40 p.m. Keith SuperDork

Then you start playing with the first number That seems to vary. Some cars like thicker, some like thinner.
Jan. 3, 2011 7:46 p.m. ea_sport Reader

Keith wrote:

If it's got Redline in the trans and diff, leave it. It's the standard for a reason.

Keith,

So which RedLine product is the right one for the trans and diff? Thanks.
Jan. 3, 2011 9:59 p.m. Keith SuperDork

Trans: I like MTL for street cars, MT90 for track cars. The latter isn't as friendly when cold.

Diff: 75W90. No Miata diffs require LSD additives, so the NS stuff is fine.
Jan. 3, 2011 10:37 p.m. pres589 HalfDork

Wow, never heard of ATE Super Blue dying the system, but I guess I haven't researched that either. Wonder what it's done to my VFR, if anything; this spring I'm going to the brown variant, guess I'll find out.
Jan. 4, 2011 8:37 a.m. Duke SuperDork

Keith wrote:

Some like it lighter, some like it heavier although usually you want to go a bit heavier. Sometimes that's just the indication that you need new oil. Remember that the first number is cold viscosity, so going from 10w30 to 5w30 won't make a difference to a hot engine.

So I want 10w40, like my old V8 Poncho?
Jan. 4, 2011 10:29 a.m. Keith SuperDork

I'd give it a try.