Oil for 1995 Mazda Miata

[mariok2006]

The car is a 1995 Mazda Miata M Edition. It has 82000 miles on it. I am the 4th owner. The previous owner says he used Castrol conventional every 3000 miles or 6 months.

My question is: Would it hurt to go synthetic, or should I stay with Conventional oil? There is a small valve cover gasket leak if it matters.

From what I have read, one can go from synthetic to conventional but not the other way around, especially on higher mileage cars.

Also, the manual says 10w30, what are some of the high performing conventional oils in this category?

I used conventional Castrol GTX in my previous car and had no problems.

 

[XPR]

I suggest Amsoil ATM 10w30 synthetic oil. You can switch to synthetic at anytime and 82000 miles isn't what I call high mileage.

Valve cover gasket should be fixed regardless.

 

[cheetahdriver]

i used Mobil 1 0w-40 for 152k in my 94M at about 8k OCI. currently using the same oil with a 10k OCI in my 02LS. with the HLA startup noise in the pre-99 engines, i would use a 0W-something, this engine likes it's oil quick and thin on startup.

 

[JGmazda]

I have a '94 and have tried many oils. My current (and best so far!) is Maxlife Synthetic 10w30. Totally quiet.

Also... the Valve cover gasket is an easy fix. Just don't torque the bolts too hard. Have you checked the CAS O-ring? Those are notorious for leaking. Near the rear of the drivers side valve cover.

You can't go wrong with any of the above suggestions. But I'd give Maxlife Synthetic a shot. Great A3 rated oil.

 

[mxhdroom]

If you're sticking with the same OCIs as the PO, GTX should be fine. I ran 10w30 GTX
in my 2000 most of last summer, but switched to Petro-Canada 5w30 Synthetic yesterday. I plan on running this oil all next summer (or probably about 8,000 km)just to see how it does. So far, it's nice and quiet. Most (if not all) of the members in our local club run synthetic of various grades and brands.
BTW, I have about half the mileage on my 2000 as you do on your '95. Most older Miata engines weep a bit around the valve cover gasket (mine does), but it's an easy and cheap fix - just adhere to what JGmazda says about torgue and the CAS o-ring.
Good luck!
G.

 

[gtx510]

You can switch to synthetic and back to dino just fine. If you've got a leak, it might leak a bit more with a synthetic oil.
A 5W30 synthetic should be fine for start-up clatter unless it's below freezing. If you don't get any HLA clatter when the engine is hot then use whatever 30wt oil you like. If you're getting some clatter then Mobil 1 0W40, GC 0W30 or Maxlife synthetic would be good choices, all are ACEA A3. But I wouldn't run them for 8-10k, imo, the Miata sump is just too small for such a lengthy OCI.
Motorcraft or TropArtic wouold be a good budget option, and you could even do a DIY synblend.

The CAS o-ring is really easy to replace. Same with the valve cover gasket. 10 and 12mm sockets/wrenches should be all you need. Only use a couple dabs of RTV to hold the gasket in place...
www.miata.net/garage/valvecover/index.html
www.miata.net/garage/cas_oring.html

Bill Wilner sells a viton CAS o-ring that should last forever. I got one for my good GTX. www.miataroadster.com

I also got rubber o-ring p/n 9954-10-3801 from www. autopartswarehouse.com for the beater.
I think they've changed the p/n to W0133-1755251. Costs $6, it's listed as fitting a 1986-94 323, 1990-98 Protege, and 1990-97 Miata.

Fel-Pro p/n 35608 might be the correct o-ring and it's $1 from www.rockauto.com
Oddly, rockauto lists 2 valvecover gaskets, $11 or $16.

 

[JGmazda]

Quote:

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You can switch to synthetic and back to dino just fine.
A 5W30 synthetic should be fine for start-up clatter unless it's below freezing. If you don't get any HLA clatter when the engine is hot then use whatever 30wt oil you like. If you're getting some clatter then Mobil 1 0W40, GC 0W30 or Maxlife synthetic would be good choices, all are ACEA A3. But I wouldn't run them for 8-10k, imo, the Miata sump is just too small for such a lengthy OCI.
Motorcraft or TropArtic wouold be a good budget option, and you could even do a DIY synblend.

The CAS o-ring is really easy to replace. Same with the valve cover gasket. 10 and 12mm sockets/wrenches should be all you need. Only use a couple dabs of RTV to hold the gasket in place...
www.miata.net/garage/valvecover/index.html
www.miata.net/garage/cas_oring.html

Bill Wilner sells a viton CAS o-ring that should last forever. I got one for my good GTX. www.miataroadster.com

I also got rubber o-ring p/n 9954-10-3801 from www. autopartswarehouse.com for the beater.
I think they've changed the p/n to W0133-1755251. Costs $6, it's listed as fitting a 1986-94 323, 1990-98 Protege, and 1990-97 Miata.

Fel-Pro p/n 35608 might be the correct o-ring and it's $1 from www.rockauto.com
Oddly, rockauto lists 2 valvecover gaskets, $11 or $16.

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Great Mazda info there! Yes... The Viton ring is better lasting. Although I must say... this Maxlife is doing a great job keeping things buttoned up. Thanks for posting the Miata links. This site and Miata.net are my two favorite car places.

 

[Kitto]

I had a 96, GC and Mobil 1 0W40 are my engine's favorite. Sold when it was 115000 miles.

 

[Camu Mahubah]

Quote:

---

I have a '94 and have tried many oils. My current (and best so far!) is Maxlife Synthetic 10w30. Totally quiet.

Also... the Valve cover gasket is an easy fix. Just don't torque the bolts too hard. Have you checked the CAS O-ring? Those are notorious for leaking. Near the rear of the drivers side valve cover.

You can't go wrong with any of the above suggestions. But I'd give Maxlife Synthetic a shot. Great A3 rated oil.

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I like this rec...I worked at a Qwikie Lube and we hated Miata's...messy filter location...so I swore if I ever owned one I would run syn and go 6000 or six months...MaxLife Synthetic...That's all I got to say about that...