Synthetic motor oil vs conventional

[Cragelarson83]

No problem! We don't mind answering repeat questions, as long as it's clear that some effort has been made. It's hard to sift through 14 years of information, and many times the information you find doesn't fully answer your questions. As long as advice is appreciated, and those giving it aren't abused (as in, relied upon with no effort to search first) pretty much anyone here is more than happy to help.

Awesome thanks so much again. I'm pretty much on this site if I'm not working or working on my car. The info on this site is extremely helpful and has stopped me from making bad decisions on upgrades. It has also boosted my confidence on performing maintenance. I can't wait to get enough posts to check out the classifieds. Every paycheck I'm buying something for my car. Of course I'm not going to post bad info or meaningless replies.

[Vermonter]

My OPINION;
I wouldn't switch to synthetic on a higher mileage vehicle. The benefits of a synthetic oil are already pointless if the majority of the engines life has been run on conventional. Some may disagree, and that's fine if their findings are different.
In every car I've owned, I have switched to synthetic (real synthetic, not the ones that claim to be), and in every single case I have noticed an oil leak that wasn't there previously. I don't mind. I just fix the leaks.
Synthetic oil will not "cause" leaks, at least not in the manner that some people say it does. Synthetic oil will not destroy gaskets or rubber. Synthetic oil has detergents. Those detergents break down sludge that conventional oil has built up over the years. Some of that sludge is acting like a dam on an already aged gasket or o-ring. It's like when you pull your girlfriends hairpie out of the shower drain... once that sludge is gone, liquids are able to pass through any available route.
People think it's a bad thing, but I like knowing when gaskets need to be changed and don't mind replacing a $5-$20 gasket.
On a high mileage or older car, the chance of leaking is much higher, and you may find some of those gaskets piss fluid more rapidly and they aren't an easy fix. In that case, sometimes just sticking to conventional is the better route. Do you really want a rear main seal leak? I'd prefer not.
I just bought a 94 with 46k miles and the P/O just did a synthetic oil change from previously using conventional. In this case, mileage wasn't even a factor. The age of the engine alone was enough to warrant oil leaks, as I would assume most of the gaskets and o-rings are original. That's a long time for rubber to dry out. Now I'm looking for a leak, and unfortunately for me it looks like a main seal.
If you are already dead set on 3k mile oil changes, just continue using conventional. The added protection of synthetic, in my opinion, will not have any added benefits if you are strict about your oil change intervals.

[deevergote]

Conventional oil has detergents as well, though synthetic does tend to loosen deposits, and find leaks more easily.

You're absolutely right, though. If you change your oil every 3000 miles (which is WAY too soon, IMO), there's no benefit to synthetic oil. Weight reduction, perhaps, as your wallet will be lighter. Otherwise, no benefit. No real added protection, except MAYBE on cold starts (though conventional oil of the proper weight should lubricate just fine.)
My 2009 Fit would go 10,000+ between changes on synthetic. It only required conventional oil. Synthetic gave me that extra mileage between changes. Since I was doing up to 2000 miles per week, that saved me a LOT of time.

[Vermonter]

Conventional oil has detergents as well, though synthetic does tend to loosen deposits, and find leaks more easily.

You're absolutely right, though. If you change your oil every 3000 miles (which is WAY too soon, IMO), there's no benefit to synthetic oil. Weight reduction, perhaps, as your wallet will be lighter. Otherwise, no benefit. No real added protection, except MAYBE on cold starts (though conventional oil of the proper weight should lubricate just fine.)
My 2009 Fit would go 10,000+ between changes on synthetic. It only required conventional oil. Synthetic gave me that extra mileage between changes. Since I was doing up to 2000 miles per week, that saved me a LOT of time.

Yeah I bought an '08 Fit in 2007 and I gave it a synthetic oil change thinking I'd own it a long time. I sold it before the second oil change. If I were to buy another brand new car, I'd use synthetic from the start. I just hate changing over to synthetic on older cars even though I always do. It has in my experience 100% of the time brought on leaks... but like I said I'd rather fix a leak I'm aware of then wait for it to become so bad that even oil sludge won't hold it in. I put royal purple in my 22re motorhome before driving from Vermont to California and back. I didn't want to do any oil changes on a road trip, and with a claim of 12k mile intervals, I figured that was a good choice. Royal purple is one of the few oils that claim to be synthetic that is actually 100% synthetic. When I did the oil change 10k miles later the oil still looked fine. A tad dirty, but nowhere near as bad as a 5k mile conventional change.

[deevergote]

Interesting. I always assumed "full synthetic" actually meant full synthetic! Now I have to research this some more.

With a new car, especially one that doesn't take synthetic from the factory, always let it break in properly before doing any changes. A new engine will come with "break-in oil", which should remain for about 5,000 miles in the case of my Fit. To be safe, I changed it out for conventional oil for the first 15-20k miles. Then I switched to synthetic. That's the only time I'd say it would be risky to switch.
And, as you said, switching a high mileage engine to synthetic when it has used conventional all its life could cause (or reveal) issues. It mainly depends on your intentions for the car. Leaks found by synthetic will eventually manifest with conventional, only probably more seriously by the time that happens.

[Grumpys93]

Conventional oil has detergents as well, though synthetic does tend to loosen deposits, and find leaks more easily.

You're absolutely right, though. If you change your oil every 3000 miles (which is WAY too soon, IMO), there's no benefit to synthetic oil. Weight reduction, perhaps, as your wallet will be lighter. Otherwise, no benefit. No real added protection, except MAYBE on cold starts (though conventional oil of the proper weight should lubricate just fine.)
My 2009 Fit would go 10,000+ between changes on synthetic. It only required conventional oil. Synthetic gave me that extra mileage between changes. Since I was doing up to 2000 miles per week, that saved me a LOT of time.

Is it really making your wallet lighter? When I do a synthetic oil change Is usually costs around 50-60 per change and I change it every 7500-8000 miles. That would net 2 conventional oil changes which would cost almost the same. Maybe save 10 dollars. But if I push it to 10,000 miles then I would have saved myself 10 dollars or paid the same. But would have saved myself the time like you stated.

This is the only reason I use synthetic, especially with my tundra and having to take off the skid plate to access the oil filter.

[deevergote]

If you do it every 3,000 miles it is. You're spending $60 every 3,000, rather than $30. Some people religiously change their oil every 3,000 (I believe the OP said he did.)
If you extend your change interval with synthetic, then yes, it evens out. That's why it's beneficial to do so, especially if you put a lot of miles on your car over a short period of time (as I did with my Fit.)

[Cragelarson83]

I don't know exactly how many miles are on my motor. It looks way to clean to have 175k. I will post pictures in the image gallery soon. I wish i knew for sure the mileage but it is what it is. Thanks again.

[hiptech]

If you do it every 3,000 miles it is. You're spending $60 every 3,000, rather than $30. Some people religiously change their oil every 3,000 (I believe the OP said he did.)
If you extend your change interval with synthetic, then yes, it evens out. That's why it's beneficial to do so, especially if you put a lot of miles on your car over a short period of time (as I did with my Fit.)

Not sure where everybody's getting their oil from but here is what I find...

I buy Mobil 1 oil on sale at Costco in a 6-pack case which usually breaks down to $4.79/qt. There is a promo right now at O'Reilly's for Castrol GTX Conventional 5 Quarts & a MicroGard Filter for $23.99 which interestingly breaks down to $4.79/qt too.

Since I have a cases of Honda filters the MicroGard is useless to me but they won't discount the price without it. Even so the Mobil 1 price of $4.79/qt vs $23.99 for Castrol GTX is the same price per quart for what may arguably be a superior oil regardless of the oil change frequency.

[deevergote]

I just pay to have mine done. 10 minutes vs. 2 hours and hassle... synthetic is about $60, conventional is about $35.

[hiptech]

I just pay to have mine done. 10 minutes vs. 2 hours and hassle... synthetic is about $60, conventional is about $35.

One reason I learned to change my own oil at an early age was when a dealership striped the drain plug, blamed us for it and charged us for a new oil pan.

But I get it not everyone wants to (or is able to) crawl under a car and get dirty...

[deevergote]

I started paying when I was working 120 hours a week. Too tired and too busy to bother with it myself! I just got in the habit of it. It still takes me a while to buy, change, and dispose of oil... and mess with stuff I see needs tweaking while I've got my tools out.

[Vermonter]

Not sure where everybody's getting their oil from but here is what I find...

I buy Mobil 1 oil on sale at Costco in a 6-pack case which usually breaks down to $4.79/qt. There is a promo right now at O'Reilly's for Castrol GTX Conventional 5 Quarts & a MicroGard Filter for $23.99 which interestingly breaks down to $4.79/qt too.

Since I have a cases of Honda filters the MicroGard is useless to me but they won't discount the price without it. Even so the Mobil 1 price of $4.79/qt vs $23.99 for Castrol GTX is the same price per quart for what may arguably be a superior oil regardless of the oil change frequency.

I honestly can't remember the details of which brands are true synthetic or not, but there are big name brands that claim to be fully synthetic and they are not. Just one of the wonderful things about USA marketing, we get to lie about stuff and sell it to the ignorant. By no means am I calling anyone dumb, just saying it's easy to be fooled if you don't do extensive research to find this stuff out. Back when I researched it, there were only 3 or 4 of the major brands that actually sold the synthetic oil they were advertising. The rest were blends of dino and synthetic being marketed as fully synthetic. Royal Purple has always been a fully synthetic oil, and the price shows it. Although you can go about 15k miles between changes, so you are really saving money in the end.
I just figure if I'm buying something for what it says it is, then I want those benefits. No point in paying more for snake oil if I can help it.
If I find the article I will post it here.

Good topic by the way.

[hiptech]

I honestly can't remember the details of which brands are true synthetic or not, but there are big name brands that claim to be fully synthetic and they are not. Just one of the wonderful things about USA marketing, we get to lie about stuff and sell it to the ignorant. By no means am I calling anyone dumb, just saying it's easy to be fooled if you don't do extensive research to find this stuff out. Back when I researched it, there were only 3 or 4 of the major brands that actually sold the synthetic oil they were advertising. The rest were blends of dino and synthetic being marketed as fully synthetic. Royal Purple has always been a fully synthetic oil, and the price shows it. Although you can go about 15k miles between changes, so you are really saving money in the end.
I just figure if I'm buying something for what it says it is, then I want those benefits. No point in paying more for snake oil if I can help it.
If I find the article I will post it here.

Good topic by the way.

This rings true of the subject of synths in general. In fact since no one has commented on the video I quoted from Savagegeese I would encourage everyone to to see it since this thread has many points that he references... worth a watch.

[wagon-r]

With the latest oil standards, all oils have to be partially synthetic to meet the criteria. Hence the confusion with marketing - they can legitimately claim to be "synthetic" even if they aren't 100% synthetic.