Question about maintenance and fuel rating

[PJR202]

full synthetic can run 10k miles or 1yr right? my service dept told me 7.5k or 6 months.

I go with the jug. We all should know by now that 3k is bullshit. There was even a pennzoil ad on the radio about 20 years ago that suggested it's good to change the oil EVERY WEEK. Ridiculous.

I do synthetic. I've ran Mobil 1 up to 10k between changes in my GT on the most recent interval, although I would normally not want to go past 7k or so since I do take it to redline at least once a day.

I've run the Mobil 1 extended performance in my Tacoma V6 as high as 14k between changes. I do use the recommended Mobil 1 filter if I can get it. I've got 150k on the truck and synthetic since 50k and I've never run it less than 8k between changes. I think my last change was 12k.

Also, the oil monitors in modern cars are pretty accurate. If I understand correctly they're based on run time, RPM, and just how long the oil has been in there..as I recall. I presume this is based on the type of oil, which I think stock in the GT is Motorcraft 5w-20, and I don't see a way the monitor can account for running synthetic so based on the benefits of synthetic it should skew the oil life monitor's data. But, the last change on the GT that I took to 10k on an advertised 10k synthetic, my monitor was at 6% oil life. That's basically on the money if you're looking at mileage vs monitor percentage.

Again, 10k is not how long I would have taken it but I was very busy and wanted to do it myself so it was delayed a bit. I ended up not doing it myself anyway. I've read GM recommends the owner planns on changing the oil when it hits the 30% mark.

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[NoVaGT]

I've ran oil samples to 19k......it can be done with no adverse affects. That was on Amsoil Signature Series.

Your oil samples may say the oil is o.k., but I don't believe it. I believe my ears at start-up, and it's clear that clean, fresh oil gets around the motor faster.

Yes, there may not be high levels of nastiness present in the oil a 10K+ miles, but that doesn't mean the viscosity is the same.

 

[nastang87xx]

In my personal case, I have used Full and Semi Synthetic with both 93 and 87 octane. I daily drive my car to work and take it on long distance trips monthly.

I have personally noticed 0 difference between any of those combinations.

Difference is about 15 horsepower at peaks. In normal driving, you'll never notice.

 

[MightyS550]

Not necessarily. The OLM kicks in around a year / 10k miles. At least it did for mine. I've ran oil samples to 19k and still had life left in previous vehicles. I wouldn't recommend that anyone stretches that long without sampling, but it can be done with no adverse affects. That was on Amsoil Signature Series.

yea exactly a year when my OLM said i need an oil change even with only 5k miles on it. I would love to do my own oil change but i dont have place to do it or is it possible to bring my own oil at some service dept lets say jiffy lube and just pay for the labor?

 

[Hashbrownn]

eh... oil change at the dealer costs $50 every 5k miles.
I think they use synthetic blend. Does it really matter if you get it changed every 5k miles?
I use 93, but I don't see an issue using 87. Spend your money how you'd like.

 

[sbrenskell]

Premium gas is recommended. Always run premium. If the extra $6 per tank for premium is an issue then you can't afford a Mustang GT anyways.

See I had no idea GTs took Premium. I always thought they took regular. But that doesn't matter to me. I can afford premium gas.

 

[SR56]

Your oil samples may say the oil is o.k., but I don't believe it. I believe my ears at start-up, and it's clear that clean, fresh oil gets around the motor faster.

Yes, there may not be high levels of nastiness present in the oil a 10K+ miles, but that doesn't mean the viscosity is the same.

They also rate the viscosity. You'll be able to see if it's going to sh*t. The analyzers will also let you know if you went too long or if it can go a little longer. The 19k was an extreme where I just didn't have time to change it. Although, I have been able to run 40k on my class 8 tractor until soot levels got too high.

 

[TomcatDriver]

Synthetic vs conventional blend. Any quality synthetic is "better" by virtually any objective standard other than price. Probably the biggest difference is synthetic maintains viscosity over it's service life much better than conventional. That is, "old" synthetic oil is going to vastly out perform "old" conventional oil. There are entire forums dedicated to the subject, and people have actually done a fair amount of testing, so don't take my word or anyone else's for it, go read "Bob is the oil guy" forum. For me the price difference is trivial. The difference between particular brands of synthetic (of same viscosity rating) is far less than the difference between synthetic and conventional or conventional blend.

 

[AGM2018]

My 2 cents on the subject of oil is to change every 5K miles with a high quality oil...I prefer synthetic (Mobil 1 Extended Performance). While modern synthetic oil will probably protect an engine for more than 5K miles, the "risk-to-reward factor" isn't worth it to me, especially while a car is under warranty. In 30+ years of driving a variety of cars (among them five 'Stangs: 65 six cylinder, 87, 98 and 03GT's and 15 EB) keeping good quality fresh oil and a GOOD quality fresh oil filter on/in your car is cheap "insurance" to ensure your car performs well for an extended period of time. The last V-8 "Performance Car" I owned was a 2006 GTO; I used Mobil 1 pure synthetic during the four years (and 60K plus hard miles) I owned it. It never used a drop of oil until the day I sold it. I plan to put Mobil 1 Synthetic Extended Performance in my new 2018 'Stang after 1K, or so miles, and change it thereafter every 5K miles.

 

[1blkpny]

Premium gas is recommended. Always run premium. If the extra $6 per tank for premium is an issue then you can't afford a Mustang GT anyways.

I agree 91 is going to be a better performance fuel but the owners manual says 87 octane is recommended. I feel use what you want. For normal driving anyway you won't feel or see a difference. :shrug:

 

[millhouse]

A bit of bullshit floating around here.

87 vs 93 octane....use whatever the hell you like. You won't notice a difference in fuel economy or power. Those that say otherwise either have a major placebo effect or had a bad tank of gas. Neither fuel is going to protect or degrade the engine mechanics or longevity over the other.

As for oil...if you change the oil at 5000 miles use whatever the hell you want (properly rated for your car of course). Keep in mind, having 8 quarts of oil greatly helps with keeping proper lubrication (less PPM of contaminants). Synthetics at typically better than their dino counterparts, but either option is going to allow these motors to last well over 200k miles.

 

[marks]

I don't know why Ford don't tune the Mustang for 93 Octane petrol as would get better compression ratios.

 

[millhouse]

I don't know why Ford don't tune the Mustang for 93 Octane petrol as would get better compression ratios.

They do, the computer just has the ability to retard ignition based off of inputs from sensors. They give you the ability to run whatever fuel you like (kudos to Ford for this).

Keep in mind, when you are already running a fairly high compression ratio (11:1), bumping it higher doesn't do much for power.

 

[PJR202]

eh... oil change at the dealer costs $50 every 5k miles.
I think they use synthetic blend. Does it really matter if you get it changed every 5k miles?
I use 93, but I don't see an issue using 87. Spend your money how you'd like.

When I realized how difficult it would be to get my car off the ground with what I had to do it with, I decided it wasn't worth my life to change it just to feel like a man. I do the changes in my truck.

I had bought the oil and filter at walmart, so I went back there to return it all and have them do the oil change. They said they can do it with my stuff, so they did. No return necessary. The fee to change the oil with my stuff? $9.00. I watched them pour it out of my jugs into the car and they gave me the leftover. And as far as I know, it didn't even have to be oil I bought from Walmart. Granted, I did wander around the store and buy $30 worth of other stuff I didn't need.

Regardless, most of the time I can go in there and get a Mobil 1 change from them for cheaper than I can buy the supplies and do it myself.

 

[00]

My old supercharged Jaguar XJR was serviced each year as per the service interval and within 10k miles with the oem oil. Jaguar had put an accurate oil pressure gauge in my model year. After about 9 months the oil pressure just fell off a cliff, the oil appeared to have broken down. This was repeated every year I owned the car
For the next model year Jaguar put in a non-linear gauge that looked OK no matter what.

That engine destroyed oil for some reason.

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