My car is comming up to 12,000 miles. In the past I've always dumped the oil and filter every 3,000 miles...............
I do for the most part 95% highway miles, which are usually at 70-80mph. I am able to work off hours, so I don't have much stop and go driving for my commute. I drive about 90 miles a day.

My question is simple......is there any advantage to going synthetic oil? Is there any gain in gas mileage or reduced wear protection with the synthetics..........
Question two.......Once you go synthetic route, can you go back to using regular motor oil again?

I have read some material on synthetics and it seems the way to go.....but is it really worth the price difference over the leading conventional motor oils........Thanks for your input
Dennis


04 cpe IP/willow/5at/prem/18's/JDM clear corners/Piaa's/MTEC H4 Super White fog/highs

 

You've hit upon one of the great religious debates. A great web resource for oil topics is www.bobistheoilguy.com.

is there any advantage to going synthetic oil?
Yes. I'm helpful already. [img]/w3timages/icons/tongue.gif[/img]
Is there any gain in gas mileage or reduced wear protection with the synthetics?
You won't notice a gain in gas mileage. You'll get increased wear protection, or reduced engine wear, which is a good thing -- the way you worded it doesn't sound so good.

Once you go synthetic route, can you go back to using regular motor oil again?
Yes. But you really should pick one or the other and stick with it.

One of the advantages of synthetic is the extended oil drain. You can run longer between oil changes (though you should continue to replace the filter frequently, unless you add a bypass filter device to the system). A big waste of money is to use synthetic, and then swap it out every 3,000 miles, IMO. Some people are happy to do that, though. Due to the extended oil drains, high-mileage (especially commercial) vehicles can actually save money over the course of a year with synthetic -- but personal vehicles generally don't get enough use to hit the break-even point. (There's an upper limit on time between oil changes.)

In my case, instead of using Castrol GTX (regular), I've switched to Mobil 1 (synthetic). I pick the stuff up at WalMart, and it's about 3x as expensive as the Castrol, but I run the 7500 mile oil changes instead of 3750, so only buy half as much over the course of a year. It works out to be a little more than 1.5x overall. (Gotta put in an extra quart when you swap out the filter at 3750.)

At 90 miles/day, assuming 5 days/week, you're clocking over 23,000 miles a year. That's definately enough to mileage to switch to something like Amsoil and change your oil only once or twice a year and go for the cost savings along with better engine protection. Although, before jumping gung-ho into something like that, you'll want to consider oil analysis to make sure your particular engine can take it. www.blackstone-labs.com is a good source for that, and again, check out BobIsTheOilGuy.

 

I dont know if I would feel conferrable not changing my oil at 3750k miles.. I like the idea of changing it at 7500k, I'm just wondering if there are any long term consequenses.
How many people change their oil at 7500k?

 

The owner's manual recommends 7500k for regular duty use anyway, so I'm quite comfortable keeping the oil in that long, but changing the filter at 3750. The filter is the big deal.. you want to keep the particulates out of the oil. Synthetic generally has a better additive package than regular oil, and can hold out against acids and other contaminates for a lot longer. But the oil analysis thing is where you get your comfort zone.. they tell you how well the oil is holding out, and whether or not going x miles between changes is a good idea for your engine.

 

Here's a link to my last oil analysis discussion thread. And in that thread, is a link to another discussion about the previous UOA.

Have fun!

http://theoildrop.server101.com/cgi/...c;f=3;t=001413


<font color=red>chinee</font color=red>
03.5 G35s

 

Ok, I'm stupid again. How do you change the filter at 3750 and keep the oil in for 7500? I guess you just remove the filter and let whatever comes out, out? And that's why it takes an extra quart?

2004.5 TB/Willow 6MT Coupe
Aluminum Pedals
BEL RX75 Pro Plus
K&N High-Flow
Other mods to be disclosed later.
WishList --
Z-Tube; Plenum; High-Flow Cats; Injen SES 1992C; etc.; etc.; etc...

 

The filter itelf will have a little oil left in it, which of course you can recirculate, but why do that. Just get a quart and top off your engine as needed.

Gurgen

 

Actually, you get better filtration in the later part of a filter's life than you do in the initial part. This is true of any filter in any application. This is because when particles get trapped on the filter, they begin to do their own filtering. You actually will get better filtration if you leave the filter in for the whole cycle. The only way leaving a filter in to long can hurt you is if it breaks through the media or begins to bypass. This is very unlikely with a M1 filter before about 10-15K miles. I change mine in my QX4 at about 8K (determined by analysis) and let the filter go the whole cycle. I intend to do the same with my new G. If you change the filter early, you miss the best filtering time.

Take if from an engineer who has spent a large part of his career in the filtration industry.

 

Are their any benefits to Synthetic blends? (regular and synthetic mixed together)

Or is this just another sales scam?



G35papa
2003 Pearl White - Premium Willow - Clear Corners (moded) - Z-tube - 18" OEMs- Tinted all around

 

Okay, check this tidbit out:
I went car shopping yesterday, and happened upon the BMW dealer. Okay not exactly "happened," but still I found myself there. They told me a bunch of stuff, but at one point said that as long as I bring it in once a year for the 15K mile check and oil change... I said, "hey, 15K miles? Are you serious? Is that because of synthetic?" They said "Yes, and as long as you bring it in on that periodicity, we can tell you that there should be no problems...blah blah blah...."

WOW! I like synthetic, because it doesn't break down like dino does. And I don't buy into the hype about engine/valve seals and breakin with dino oil, etc. Many many very expensive and/or exotic cars come from the factory with Mobil 1 synthetic in the pan. But (and it's a J-Lo big butt), 15K miles between oil changes seems extreme.

As far as extending the 3K mile intervals on synth, though, I would say that it can be safely done, especially with non-harsh miles put on (highway, full warmup before high RPMs, etc). I don't know if I would go beyond 5K miles or 1 year, though.

As far as synth blend, I would say that it has inherent advantages, such as extended (slightly) change intervals, better lubrication break down resistance, and better summer capability.

My .02 Or maybe a nickel. Damn I'm wordy sometimes!

 

I did a little research on bobistheoilguy.com. THere are some seriously knowledgeable guys out there..

Anyway... in fact you CAN change some oil every 15,000 miles, even 20-25K. The operative word being "some". There are very few of the out there that will last that long. There are 2 other guys on this forum that are into the oils and are also members on the said site. Amsoil, Redline, German Castrol are prolly hte only ones that can be used for along period of time, I am not sure about Mobil 1. It should be said that M1 synthetics generally return very impressive results upon oil analysis (planning to send mine in), and most do not use it beyond 7K miles. Given that I drive my car REALLY hard, I use M1 5w-30 synthetic EXCLUSIVELY because of the good availability. Otherwise I would be using Redline or Amsoil. I am plannig to switch to Redline 10w-40 (a much thicker oil) when I install the TTs.

Also, I strongly disagree wth the assertion made above about not changing the filter for a while. I would NEVER go with a used filter for more than 4K miles. The particles MAY increase filtration, but that will result in a large drop in oil pressure! Low oil pressure can hurt.

Gurgen