silverzman

Hi Guys,

Sorry for another thread on oil, but wanted to get your quick opinion. I'm approaching my first oil change and after reading all the threads I'm even more confused. I've narrrowed it down to two options:

1. Use Mobil 1 and change every 5k miles or so (is that a good interval, seems like a waste to change every 3K miles with this stuff)
2. Use a regular mineral oil and change every 3k miles (BTW, what is a good min. oil?).

What are your thoughts???

All info is greatly appreciated!

ChinaClipper

iTrader: (2)

Hello silverzman (from a fellow CS owner!),

My own thoughts on oil. Oil is like shoes or hairstyles - there are many opinions and it is a personal decision. Do what is comfortable for you. I am the original owner of a 1972 240 that has never had anything other than Quaker State mineral oil that was religiously changed at 3K-4K intervals. The insides of the engine are clean as a whistle with no deposits or varnish at all. For my Honda 4-cylinder, Castrol GT gave me a bit more MPG. Changed every 3700 miles, the inside of the engine are also clean and shiny at 260,000 miles on the odometer. I believe that it is more important to regularly change oil at no more than 4K intervals than what kind of oil you use - just stick with one brand and don't switch between brands.

Others may have other opinions, I am sure.
Good luck on whatever you decide!

VaGentleman

Just a question. Isn't the time (months) between changes also important. The additive package that is present in oil breaks down in relation to both mileage and time doesn't it?

The only reason I bring this up is because I usually only put 7.5K miles on my car/year. If I just changed it every 3-4K miles, I'd end up changing it every 6 months.

I'm thinking that my first oil change will be at the end of January (4 months time and probably about 2K miles)

Any comments would be appreciated.

VG

ChinaClipper

iTrader: (2)

VG - but of course you are correct! Time interval betwen oil changes is also important. I put about 20-25K/year on my vehicles, so mileage is important instead of time to my driving habits! Texas is mighty spread out!

silverzman

Thanks guys!

Follow up question for ChinaClipper: Why don't you suggest switching between brands. I haven't heard that before.

ChinaClipper

iTrader: (2)

Of course you switch brands when first breaking in a new car. My advice here is for those who change their own oil or specify the oil used in his/her vehicle once a choice of oil brand is made. It is simply the detergent levels between different brands of oil. All oil has detergent in it to help keep the engine insides clean. Some have it more of it than others. Years ago on my old Mustang, I mistakenly switched from running Valvoline to 5 quarts of Pennzoil. Much to my dismay, the engine oil got dirtier quicker as the higher detergent level in Pennzoil did some cleansing of my engine crankcase, resulting in poor performance and fuel economy until I changed back to another brand. This was just my experience, and I still to this day avoid Pennzoil like the plague. I will admit that these days, burning unleaded fuel and with fuel injection, the buildup of varnishes and internal soot in the engine is much less than in the 60's. Still......
BTW, I am unconvinced of the utility of synthetic oils versus their cost. No doubt if I raced the car or the car experienced extremely high or extremely low temperatures as a rule, it would provide benefits commensurate with the cost. I just don't think the added benefits are realized by my driving habits or style, and it is not worth the increased cost.

apex locator

iTrader: (5)

i changed to 5w30 mobil 1 after the breakin period, and thats the oil i'm staying with. once the z gets boosted i'll probably change to a heavier weight mobil 1.

Michael-Dallas

Here's my $0.02...

Unless you plan on attending track events or playing in the upper rpm band on a regular basis, then conventional oil will be ok. The most important thing is to change your oil every 3k miles, whether it's conventional or synthetic oil. And here's why:

When you have a film of oil between 2 surfaces, imagine the extreme pressure placed on it. When that sort of pressure is applied, the oil either exits the 2 surfaces or breaks down. Imagine conventional oil as a M&M and synthetic oil as a Skittle. If you step on the M&M and Skittle, you will notice that both will crush and flatten. The same effect happens to oil molecules, regardless if it's conventional or synthetic.

Where synthetic offers more protection is in the area of thermal breakdown and viscosity consistency in the temperature range. Synthetic has a higher flash point among all things. Using the M&M and Skittle example, the Skittle will melt at a higher temperature than the M&M.

Oil should be changed every 3k miles/3 months, which ever comes first. The reason for every 3 months is that the engine contains chemical byproducts from combustion that may chemically react w/ oil and become acidic.

Michael.

silverzman

Michael: It looks like you've had a history with Nissan cars. What's the oil you've had the most success with?

I've always owned Hondas and Castrol GTX seemed to work best for me. I've also been told to avoid Pennzoil like the plague.

Michael-Dallas

I'm assuming you're asking me? (ChinaClipper is also a Mike and has a history w/ Nissans as well )

I've only used Mobil-1 5W30 or 10W30 in my cars. The SE-R regularly sees the 7500rpm redline and synthetic for a turbocharged car is a must. I plan on hitting driving events w/ the 350 so I'm using Mobil-1 for it as well.

When I bought my first Z, a 95 300ZX non-turbo, I used Castrol GTX for a short period of time, then moved onto Castrol Syntec, then finally stuck w/ Mobil-1. At the time, I didn't know jack about oils -- just name brands -- so there was really no compelling technical reason for the brand/type switching except for marketing. I switched to Syntec because I wanted to try synthetic and I switched to Mobil-1 because of the name heritage and factory fill on some high-end cars. Now, after reading about oils, I personally feel that Mobil-1 is the right oil for me. It's a "synthetic" and it's more affordable than the true synthetics (i.e. Redline, Amsoil, etc.) that cost twice as much.

If anything, heed my words: any oil will work, just change your oil regularly at every 3k miles (or 3 months). Don't believe the myth that synthetic oil will extend oil changes. The only thing that would extend an oil change would be a larger oil supply.

Michael.

BTW, I'm not 100% sure, but Courtesy Nissan and Bankston-Lewisiville use Pennzoil.

WayneTN

Yeah, Michael. Is it M&M's or Skittles? Inquiring minds want to know............

WayneTN

Michael-Dallas

Man, try and come up w/ an example and this is whatcha get...

Michael.

ChinaClipper

iTrader: (2)

The truth of the matter:
Michael-Dallas is a Skittles and M&M man, while
ChinaClipper (AKA Michael-Rockwall) prefers SweetTarts!

sessions

Forgive me if this is common knowledge, but is it true that once you've used mineral oil for awhile, synthetic won't do you any good?

I'm trying to get a few thousand more miles out of my old Sentra (go ahead and snicker, those of you with nice cars) and I'd pay a little more to do it.

See, the longer I drive the Sentra, the better Z I'll be able to afford.

RoadRagerInTherapy

Is that M&M Peanut or Regular?

Great analogy Michael-Dallas!

Michael-Dallas

IMO, synthetic is not necessary unless you are rough on your car(s). I can't iterate enough how important regular oil changes every 3k miles means more than conventional vs. synthetic.

But to answer your question, I can only speak of my experience: I bought my SE-R at 67k miles and since my ownership, I have used Mobil-1. It now has over 86k miles and it does not burn a drop of oil. And I use Mobil-1 in it because I'm VERY rough on my SE-R. The only times it doesn't see redline is when my parents are riding w/ me.

Your mileage may vary.

Michael.

Flyingscot

Well, mine hasn't. That SR20 motor is incredible. Mine has 140,000 hard miles over 11 years, plus 50+ hours of track time and I'm still trying to kill my first motor (so I can get the more powerful JDM version)

Fly

ttheisen93

What do you think about changing the oil in the first 20 miles, then at regular intervals thereafter? I was reading a website on engine break-in that recommended changing the oil after the first 20 miles, as that is the oil change with the most little bits of metal, flotsam, jetsam and detrius in it.

Craig

Flyingscot

There's two ways to answer that.

1. Doing it won't hurt.
2. On my Sr20 motor, I did my first at 3,500miles and after 140k miles, the compression is still excellent. In fact, 3 of the cylinders are within a few pounds of the factory spec. So you see, it makes little difference in modern engines.

Fly

silverzman

I average about 6 oil changes a year and I calculated using Mobil 1 is about $15 more per oil change than the regular stuff. So on a per year basis, that only about $100 more. Definitely worth the extra protection IMO for a $30K car.

Does anyone know the cheapest place to buy Mobil 1? The best price I've found thusfar is Costco for ~$23 for six.