Tag Archives: mobil1

Mazda MX-5: Diff Fluid Change With Castrol Syntrax 75W-90 Synthetic

Another unseasonably warm day this February with tropical like heat wave weather so I did some more maintenance on my Miata in preparation for the Road Trip to Florida next week.

Was the gear oil due for a flush? Nope… not necessarily. I was about 9k miles short of the scheduled change. However, I thought I heard a little whine coming from the rear end on a recent trip down the Jersey Shore for the Millenials Miata meet, so I decided to flush out the Mobil 1 I put into the diff at the end of 2015 and replace it with Castrol Syntrax 75W-90 synthetic.

As usual this was a two step process. Once I decided on the Castrol (and part of my decision was based on the engine oil I just started using – Castrol EDGE… not that engine oil has anything to do with the diff, I figured I’ll keep things consistent), I researched where I could buy it. First I found O’Reily Auto Parts sells it for about $14 bux but we don’t have any of those stores around here. Pep Boys and Advance Auto did not advertise it on their web site, Walmart could place an order for me for about $13 but surprisingly Auto Zone had it in stock for $9.99! I still wanted it cheaper, so I went on CardBear.com researched AutoZone gift cards and bought one from Raise.com saving about $3 bux! The gift card showed up in just a few days since I ordered it and as soon as it arrived I rushed out the door to my local Auto Zone to pick it up.

It was definitely convertible weather today!

It took no time to jack the car up and get it leveled to do this job, but once it was in the air I could not (for the life of me) find the necessary 23mm and 24mm sockets to do the actual job! Fucking hell…. I searched everywhere, wasted more than an hour looking to no avail. So I went to the local Lowe’s to pick up two sockets so I have them for the future. I stopped by my local Sears to see if they had Craftsman in stock since I have some Shop Your Way rewards points to burn but the 23mm socket is a high commodity only available for online orders… the price for the 24mm socket was $12 or $13, I picked up both sockets at Lowe’s for under $10! I think they were $4.88 each plus tax which seems very reasonable. (Though I’m sure I could have bought them for way less if I had the luxury of time).

Anyway, the job itself took no time. Very easy to undo the top bolt, then the bottom to drain the diff. Cleaned everything up. Put the bottom bolt back on. Jerryrigged a device to pump the new fluid into the diff, and then tightened both the bottom and top bolts. Surprisingly I was able to pump almost the entire bottle in this time, I think I pumped less with Mobil 1 a year ago, but I could be wrong.

So there it goes. Easy job. I’m hoping this one lasts more than 20k miles before the rear end starts making whining noises again. I should mention I was very surprised how dark the Mobil 1 gear oil got… many of you will remember I said the same thing about my Mobil 1 engine oil the first two oil changes I did. I just don’t know what makes that oil turn so dark so soon.

Some people claim that the oil is so good it takes all the dirt out of the system that’s why it turns so dark. And that the other oils I use are not as good and therefore not as dark when I flush them. But I call BS on that! There’s no reason why the rear diff fluid should be this dark at just 20k miles. I think it should have lasted longer. I guess time will tell when I flush the Castrol Syntrax for a direct comparison.

I took a short 2 mile drive down to the local Advance Auto to responsibly dispose of the used oil, and the diff feels just fine. Nothing to talk about… it’s smooth, there’s no noise. It’s good!

Will follow up again when it’s time to flush it in 30k miles.

Mazda MX-5: Oil Filter Options for NC Miata

If you’ve come for a scientific comparison for the “best” oil filter to use on your next Miata oil change… you’ve come to the wrong place.

The goal of this post is to illustrate, side-by-side comparison between some of the oil filters I’ve already used on my car and some I intend to try. I have used the Mobil 1 M1-102 filter with my Mobil 1 oil changes when I first got the car in 2015. In 2016 I switched to a K&N HP-1002 filter that features a 1 inch nut on the bottom of it for easy removal. And in 2017 I purchased a cheaper version of the K&N called PS-1002 that doesn’t feature a nut on it, and is apparently of lower quality (also Made in China, not in USA like the Mobil 1 or K&N HP-1002). That said the K&N HP-1002 filters I sourced from Walmart recently must be old stock. I used a K&N filter last year sourced from Advance Auto that was made in South Korea, I believe. So these filter options are always evolving.

Here’s some side-by-side shots:

K&N PS-1002 (Pro Series)

K&N HP-1002 (High Performance)

Mobil 1 M1-102

Notice it doesn’t come with the plastic wrap to keep the dust off.

The M1-102 and HP-1002 are very alike, directly comparable, while the PS-1002 is clearly of cheaper quality. The can has a flimsier feel to it though it still has a plastic cover to prevent dust getting into the filter while its in a box.

Price wise I have purchased the Mobil 1 for around $10 from Amazon. My latest K&N HP-1002 I sourced from Walmart for under $10 apiece. I bought 4 of them to get FREE shipping. Before that I purchased the HP-1002 from Advance Auto as part of the oil deal, they were included free in the purchase of a 5QT jug of Pennzoil Platinum 5W20 oil and a rebate from the store. The PS-1002 I just bought from AutoZone who had a $3 OFF promo, the filter came out to $3.50 apiece with FREE shipping. The boxes arrived directly from K&N manufacturer in Riverside, California even though I ordered on the AutoZone web site.

As part of the same AutoZone $3 off deal, I ordered a longer K&N PS-2009 filter. I had researched on forums that the PS-1002 and PS-2009 are identical except for the volume of oil they contain. Presumably higher volume filter does more of the filtering, while flowing the oil better through the system. Or some-such…  There’s a longer oil filter option for the NA & NB Miata’s but not so for the NC. People claim that the longer filter will not fit into the tight space on my Miata. At $3.50 a pop I was willing to buy one to try it for myself. Though I have to admit that I believe the people claiming it won’t fit because my 2007 Miata has been around for ten years already, the NC was made from late 2005 to 2015, so I’m sure if they fit someone would have tried it and would have been offering them for sale to make money on this “better” option product. But again, I’ll find out for myself during my next oil change in about 5k miles.

Here’s the pix for comparison:

K&N PS-2009

And more side-by-side:

So far I have no complaints using Mobil1 M1-102 or K&N HP-1002.