Miata Synthetic swtich

  • Thread starter Thread starter Boz Mon
  • 30 comments
  • 7,729 views
Boz Mon

Boz Mon

Messages
1,478
Long long ago, when I had my Prelude, I briefly switched from Valvoline dino oil to Mobil 1 synthetic. Needless to say it was a failure. It used almost 2 quarts between changes, and I did not have any noticeable gains in fuel economy or anywhere else for that matter. That along with 40 something dollar totals for oil and a filter steered me back to dino oil.

Fast forward like 3 years. I now have a Miata with around 30k miles on it and I want to see what this thing does on Synthetic. I have once again, been using Valvoline 5w30 for changes. Thus far, I have not had to add any oil between changes on the dino oil. Today I am going to switch to synthetic (Mobil 1) and see how it goes. If nothing else, I have been informed that the extended oil change interval will be worth it.
 
I use synthetic on all of my vehicles. It doubles the time between oil changes for double the price - so the cost is a push. The upside is that it reduces wear on your engine.
 
^ that

Although weaning an older vehicle to synthetic may not be the best thing as all the sludge buildup will get cleaned out, and you may find oil leaks.
 
I've never had a car of any age that leaked more with synthetic, and I currently own cars ranging from 34,000 miles to 270,000 miles. In a 30,000-mile Miata I don't forsee any issues at all.

I say change the Miata to synthetic and never look back. As Dan says, go 5k-7k between changes, spend the same money, and get under the car half as often. I use Mobil1 myself, $24 for 5 quart jug at WallyWorld. Get a good Wix/NAPA or even factory Mazda filter and avoid both Fram and Purolator like the plague (I've had very bad luck with both). Also, I don't use Castrol's (American) synthetic because it is actually a blend, not full synthetic.
 
Well If the car already leaks it does leak more. ;) I know that much. :lol:
 
I just put the Mobil 1 into the Miata. It did seem a lot smoother on startup but that may just be a mind game. I always use fram filters. I have had 5 cars now and done a TON of miles on all of them with no problems with fram filters. We'll see how this goes, hopefully no oil usage.
 
Danoff
I use synthetic on all of my vehicles. It doubles the time between oil changes for double the price - so the cost is a push. The upside is that it reduces wear on your engine.
Click to expand...
Exactly.

I decided to put synthetic in Heathers Saturn for the heck of it earlier this year. With regular oil I would have to add at least half a quart every few weeks. But to my surprise the synthetic did very very well in her car and I never had to add any oil after 3 months. :dopey:
 
Boz Mon
I just put the Mobil 1 into the Miata. It did seem a lot smoother on startup but that may just be a mind game. I always use fram filters. I have had 5 cars now and done a TON of miles on all of them with no problems with fram filters. We'll see how this goes, hopefully no oil usage.
Click to expand...

Shame on you! :p

Nothing but OEM filters for my cars. Also, we use Redline synthetic in our shop cars, and a lot of customer cars and have seen no ill side effects. 👍
 
Interested to hear what you think after a few miles. Oil change coming up on my Miata too so might consider switching to synthetic if it turns out to be worth it.
 
I also use Fram filters whenever I can. I have seen stock oil filters crack a couple times. Some of the stock oil filters have very thin flimsy side walls.

This is especially the case on older muscle cars. Probably not as critical on newer cars.
 
Duke
I've never had a car of any age that leaked more with synthetic, and I currently own cars ranging from 34,000 miles to 270,000 miles. In a 30,000-mile Miata I don't forsee any issues at all.

I say change the Miata to synthetic and never look back. As Dan says, go 5k-7k between changes, spend the same money, and get under the car half as often. I use Mobil1 myself, $24 for 5 quart jug at WallyWorld. Get a good Wix/NAPA or even factory Mazda filter and avoid both Fram and Purolator like the plague (I've had very bad luck with both). Also, I don't use Castrol's (American) synthetic because it is actually a blend, not full synthetic.
Click to expand...
This. Except I do use a K&N oil filter since its easier to get off. Couldn't be much more of a PITA on these Civics.


Edit: And to anyone with RX7s/8s, its not recommended to use synthetic oil (and I think it actually voids the warranty on an RX8 in the US) because not all of them burn well, as a rotary is supposed to do. Interestingly enough, in Japan that's what they are supposed to use, but they have a tighter control on their oils I suppose.
 
I ran synthetic in my old Civic. I still changed it at ~3,000 miles (5,000km actually, speedo was in km) but I just did it because it was better for the car. I will say though, after running Mobil 1 for years, the week before I crashed it I switched to Royal Purple. In my mind the car felt a good bit smoother with Royal Purple than with the Mobil 1.
 
I've never quite understood how people can be extremely biased to a particular brand of oil just by driving the car. I could see it if, after multiple oil analysis', one brand consistently showed less wear and a longer life.


Also everywhere I've read about people changing synthetic oil at 3000 miles is just throwing away money.
 
I've been running Mobil 1 in our '95 Miata ever since we bought it, and it just doesn't seem to degrade. I change it as a matter of course every 5,000 miles, but given that we've only put about 20,000 miles on the car in the 5 years we've owned it, it's generally more because I'm worried about the age of the oil than the condition, as it seems to maintain a good golden brown colour throughout it's life.

The hydraulic clutch fluid on the other hand...
Well, it has a small leak on the clutch master cylinder, but it doesn't really get used enough to justify swapping, and a quick check & top off with DOT-3 Brake fluid does the job.

I was tempted to try synthetic in the 911, but the Porsche mechanic didn't recommend it for the notoriously leaky 3.0 B6, especially one with ~150,000 - 180,000 miles on it (The car has had an odometer swap so the real mileage is unknown...) and given the fact that there's almost 12 quarts in it, I'm thinking it's not a bad thing as that'd cost a small fortune in Mobil 1!!!! I currently use Castrol High Mileage 20W-50 for that one.
 
Yea, I'm thinking if all goes well, I will change this oil out in about 5000 to 6000 miles. I have heard of people going as long as 15000miles on synthetic. I wont be going anywhere near that though.

My main concern is the oil usage. Currently using none between changes, I dont like the idea of adding. Like I said before, only time will tell so I can develop a good opinion of the stuff.
 
Smallhorses
The hydraulic clutch fluid on the other hand...
Well, it has a small leak on the clutch master cylinder, but it doesn't really get used enough to justify swapping, and a quick check & top off with DOT-3 Brake fluid does the job.
Click to expand...

Did you check that the slave cylinder isn't leaking? The Slave tends to bite the dust way before the Master will. Make sure you pull the boot back, as from the outside it can look like it's still good.
 
R1600Turbo
Did you check that the slave cylinder isn't leaking? The Slave tends to bite the dust way before the Master will. Make sure you pull the boot back, as from the outside it can look like it's still good.
Click to expand...

Sorry, my mistake, it is the slave cylinder :dunce:, I just spaced while I was typing that and put master by mistake! I just had a 5,000 mile service done on it, front brakes changed, oil & filter change, and had the new steering wheel fitted (finally!)

dscn3261k.jpg


and the Mazda dealer let me know that it was a minor leak on the slave cylinder that was present, as I'd asked them to check it out due to the greater than normal use of clutch fluid.
Apparently it only leaks in a small way when the clutch is depressed, so it's a case of not sitting long with the clutch disengaged, which is a good habit anyway, and something we both tend to avoid if we're sitting at traffic lights.
I'll get it done at some point, but a new starter motor for the 911 took precedence for the moment.
 
Eric.
And to anyone with RX7s/8s, its not recommended to use synthetic oil (and I think it actually voids the warranty on an RX8 in the US) because not all of them burn well, as a rotary is supposed to do. Interestingly enough, in Japan that's what they are supposed to use, but they have a tighter control on their oils I suppose.
Click to expand...

That's something Mazda USA would say while Japanese RX owners uses specialty sythetic oils. Idemitsu, which is Japan's largest lubricant manufacturer makes a full synthetic specific to the Wankel Engine. If I have an RX-8 I'll wait for the warrenty to expire and use Idemitsu where needed. Partly they and Mazda have collaborated in the past like winning the 1991 24hrs of LeMans.
 
Eric.
This. Except I do use a K&N oil filter since its easier to get off. Couldn't be much more of a PITA on these Civics.


Edit: And to anyone with RX7s/8s, its not recommended to use synthetic oil (and I think it actually voids the warranty on an RX8 in the US) because not all of them burn well, as a rotary is supposed to do. Interestingly enough, in Japan that's what they are supposed to use, but they have a tighter control on their oils I suppose.
Click to expand...

I like K&N filters as well.

But to your comment about the synthetic in rotaries Racing Beat says that Royal Purple is great stuff and I think so too. Never had a problem with at all. :)
 
The general consensus is to stay away with a couple exceptions. Not all dino oil will work well, and not all syn will work well.
 
Nice to see my thread bumped. A small update, as of this week, I'm about 2000 and change miles into the synthetic switch with no signs of any oil being used.
 
Smallhorses
Sorry, my mistake, it is the slave cylinder :dunce:, I just spaced while I was typing that and put master by mistake! I just had a 5,000 mile service done on it, front brakes changed, oil & filter change, and had the new steering wheel fitted (finally!)

dscn3261k.jpg


and the Mazda dealer let me know that it was a minor leak on the slave cylinder that was present, as I'd asked them to check it out due to the greater than normal use of clutch fluid.
Apparently it only leaks in a small way when the clutch is depressed, so it's a case of not sitting long with the clutch disengaged, which is a good habit anyway, and something we both tend to avoid if we're sitting at traffic lights.
I'll get it done at some point, but a new starter motor for the 911 took precedence for the moment.
Click to expand...

Wow, looks beautiful. Can I buy it? :sly: this is exactly the kind of Miata I'm looking for, garage kept and low mileage
 
Picked up an Amsoil flyer the other day...anyone got any experience with that brand?
 
I run Amsoil trans fluid...

I don't see the need to spend more than what Mobil1 costs for motor oil (which is roughly $25/gallon). Unless you road race or something and NEED something extra-protective. Honda dealerships even put in Mobil1 Full Synthetic if you ask for synthetic (not sure what their standard dino oil is, I'd assume Mobil1 also, they likely have some sort of partnership).
 
Eric.
I run Amsoil trans fluid...

I don't see the need to spend more than what Mobil1 costs for motor oil (which is roughly $25/gallon). Unless you road race or something and NEED something extra-protective. Honda dealerships even put in Mobil1 Full Synthetic if you ask for synthetic (not sure what their standard dino oil is, I'd assume Mobil1 also, they likely have some sort of partnership).
Click to expand...
All Mobil oils labeled "Mobil 1" are fully synthetic. They use the "Mobil" name for conventional or synthetic-blend oils, and blends will be labeled as such.

enlargedmobil1family.jpg


I think Mobil 1 is one of the best road car synthetics. It's a "real" synthetic because it's based on polyalphaolefin. Most "synthetic" oils sold in the US aren't "real" synthetics because they're what the government calls "group 3" sythetics. Only categories higher than that are real, full synthetics. For example, Mobil 1, Redline, Amsoil, and Royal Purple are sythetics that you're able to run through a rotary engine. Rotaries burn oil by design for lubrication, and that requires an oil that actually burns. Conventional oil burns great, real synthetics burn too, but fake synthetics don't and will foil a rotary in no time.

The reason I like Mobil 1 for street cars is because it's a street oil, which means it's designed to work for a long time. Oils like Redline and Royal Purple don't have the same cleaning detergents and stuff that help keep oil passages clean because they're designed for high-performance, low-friction applications. Lubrication and detergent properties are a compromise, it can either lube well or keep it clean but it can't do both. Mobil 1 is more practical than the others for a car with lots of miles and long change intervals. For instance, if BMW really wanted that 10 extra horsepower they might recommend Redline or some equivalent racing oil instead of Mobil 1.

/somewhat scientifically based opinion

Anyways, I never had oil burning problems in either of my VTEC Hondas when I ran Mobil 1. Now I'm out of the synthetic game though. The Rex burns too much gas and needs changes too often to justify the sythetic prices.
 
I've had my Miata for 12k miles and have done 4 or 5 oil changes, all were with 10w-30 Castrol Edge. I just bought a jug of 5w-30 Mobil 1 with Mobil 1 filter. Hope it doesn't burn oil or cause my lifters to tick after 1,500 miles.
 
fitftw
I've had my Miata for 12k miles and have done 4 or 5 oil changes, all were with 10w-30 Castrol Edge. I just bought a jug of 5w-30 Mobil 1 with Mobil 1 filter. Hope it doesn't burn oil or cause my lifters to tick after 1,500 miles.
Click to expand...

The motor I put in my car was used and had 110k miles on it and I ran Redline synthetic exclusively. Never had an issue.
 
When I got my Prelude engine in, I went straight to Pennzoil Platinum. I've only put about 1.5k miles on the motor (already had 49k on it), but no problems yet. Good color, smell, level's still unchanged. No leaks and it runs very smooth. I might try other brands to see if any feel noticeably different.
 
Sweet threadbump! My switch is still a success. I'm doing 6,000 mile intervals, and it uses no oil between changes.
 

Latest Posts

Back