Synthetic oil or not?
 

I'm new to the website and did some searches in the archives but could not get a clear verdict on synthetic oils. As of yet I have not tried it. I've been a die hard valvoline guy, seeing how clean it leaves an engine even after 100,000 miles using it. I've seen advertisments and have heard that synthetics can increase hp & mpg. I know it's more expensive. Do syn users still change their oil at the same intervals? Does it keep a motor clean after many miles of use? In the end does it cost more than it saves? Better or worse in harsh winter temps? What are the most proven brands? Would be used in a civic. Thanks

It's my opinion that whichever type of oil is recommended by the car's manufacturer is the better choice, because you won't know how to figure the optimum service interval if you change.

My VW specified not only synthetic, but synthetic that has been tested by VW and passed. They've got a long list, but it's tough to find approved oil in WalMart (despite their huge selection of brand name synthetics). I was able to find at least two in the smaller selection at an auto parts store. The service interval is 10,000 miles.

With basic synthetic at 3x the cost of premium normal non-synthetic oil, I doubt it can pay for itself unless you can triple your service interval. I don't think you'll find measurable FE gains unless you go to a significantly lower viscosity.

Yes, synthetic is superior, but in my observation, it's an unnecessary level of superiority. I don't hear about many (any?) modern engines with failure/wear that could have been prevented by using different oil (assuming the maintenance schedule was followed). I suspect that most engines fail from other problems or are junked with the car long before oil-related wear is a problem.

Synthetic motor oil is barely 50% more expensive than dino juice but I can double the oil change interval. 1 gallon of she'll rotella 5w40 is $16 and 5 quarts of supertech 5w30 (rebadged mobil1) is $14. Synthetic oil pays for itself on the longer interval alone.

I've been using synthetic oil (Castrol Syntec, will change to Amsoil soon as my next oil change is due) for the past 50K miles on my vehicles. the first 50K miles were on conventional oil. the difference is apparent, my cars run better on synthetic oil. I save money on it as well since I don't follow the 3K miles oil change interval anymore. I change my oil every 6 months, no more, no less. I am planning on switching to Amsoil so I would only have to chnage oil once a year. Also planning on changing my tranny oil to Royal Purple which I've been hearing good things about.

my cars also starts better in the winter time since I've started using synth oil, before that it was a b*tch during winter.

I am not a mechanic, nor an expert in the automotive field, but my experience with synth oil has been good.

I'm a cheapskate and I like quality.
I ended up deciding to use WalMart's house brand of synthetic, SynTec (Super Tech??). It's about $14 per 5-qt. jug. I'm sure Mobile 1 is better but it costs approx. double what I pay for this stuff. Maybe it's Mobil 1 as tjts1 says. I used to change dino oil at 3-3.5 K mi. intervals, in my '89 Volvo. I run the synthetic about 6-7K miles now but I'm very approximate about that. I let the wifemobile go 10K miles just recently due to lousy winter weather and other interferences.

Winter startups have been fine with 10-30 synthetic. Our Nordic beasts have always started well in winter but if anything starting has been easier with synthetic.

My own decision was to stay within the various viscosities spec'd by the mfg. In my climate I can use 10-30 or 15-40 so I use 10-30 based on the principle that thinner is better for FE. When our 3rd car was a 'leaker' I used the thicker stuff to reduce the leakage but that was Dino oil.

BTW there's some 'wisdom' out there saying not to use synthetic on an old engine that's been run on dino oil, that the seals will leak and you'll be sorry. Also that loads of old gunk will be freed up to circulate in the oil. I didn't have problems with either of the 2 very old Volvos I switched to synthetic. However we're committed to the cars and on one of them I had rear seals replaced before I went to synthetic because it was leaking pretty badly.

In my car before switching to synthetic I ran some GUNK crankcase cleaner, but only for about 1/2 the time spec'd on the can. Then swapped in fresh dino oil to 'rinse' it for a spin around the block, then put in synthetic and a clean filter.

Then I changed out the filter after running 1000 miles on synthetic. If I recall I left the oil alone, just changed the filter in case it got loaded up with old junk that was released by the synthetic lube. Cheap insurance, I figure.

Wal-Mart Supertech synth is NOT rebadged Mobil1. It's made by Warren Distributors (not the same Warren as Warren Unilube which makes Coastal)

What you may be confused on is the fact that ExxonMobil supplies dino in some regions that are rebadged as Supertech Dino.

Rotella T Synth 5W40 is great oil but if your car specs a 30 weight and your an hypermiler you're going to add a tiny bit more drag by going up to a 40 weight. Maybe insignificant, but.....


Synths will, for the most part, leave an engine cleaner after a while than dino will. But for the most part, today's dinos are fine at the factory spec'd intervals. Now, if your car specs a certain type of synth, by all means use it.

brucpick, folks who've actually had big problems switching from dino to synth at high miles are few and far between.

Most agree that quality synthetics are better. The question becomes, "better enough to justify the price?". And that's where you will hear differences of opinion.

Depends upon the syn user. Personally, I go with very high quality synthetic (Amsoil, if people were wondering), along with very high quality filters. Than I do NOT change my oil as often, as both the oil I'm using and the filters are rated for very long oil changes.

As a result, I actually save on oil changes, as the extra costs of the filters and oil is LESS than I save by not changing them as often! And that doesn't even count the increased fuel economy I get with a quality synthetic.

It's been my experience that a quality synthetic oil, combined with a very high quality oil filter (cheap/standard oil filters don't do a good enough job of keeping dirt out of the oil) can do an amazing job of keeping an engine clean.

However, you have to buy upon specs and independent tests, as costs (by themselves) are not a good indicator of how good the oil (or filters) are. And surprisingly (sadly) a number of big "name brands" often take shortcuts that make their synthetic oil (and their oil filter) offerings less spectacular than you would expect from the brand name...

Done right, it saves more than it costs. Because while the oil changes will each be more costly, you can change it out less often (as long as you monitor things, and don't do silly things like let the oil level drop too low). And so just the savings on fewer oil changes can pay for a good synthetic, never mind how it makes the car run better.

Usually better. In fact, some synthetics are dramatically better in cold weather than conventional oils are! And that's even more likely to be true, if you replace your 10w30 with a quality 0w30 (a safe replacement, as both oils are 30 weight once they warm up to temperature).

NOTE: The number before the "w" is the COLD flow rate, and the number after the "w" is the HOT flow rate. Generally speaking, you can safely have the COLD rate (the first number) be LOWER than car spec, without much danger. And the lower the first number (which is why I like 0Wx synthetics), the better the performance in bitterly cold temps! The important thing is to have the 2nd number be big enough (if you want to be safe, go no lower than the owners manual specs on the 2nd number), that the oil isn't "too thin" after your engine warms up.

What this means in practice, is that you can easily/safely replace a 5w30 or a 10w30 with a good 0w30. OTOH you might run into problems if you try replacing a 5w30 with a 0w20 (because the 0w20 is only a 20 weight oil once it warms up).

Some things to watch for, however:

There are some dangers when first switching from a conventional oil to a synthetic. Specifically, a synthetic usually flows freer than a conventional oil does, so any tendency for an engine to leak oil will initially be worse then with a conventional oil. Also, conventional oils often leave deposits/sludge behind over time, and most quality synthetics are good at cleaning this stuff up. This is overall a good thing, but there is a risk when first converting from dino oil to a synthetic, that you can actually break loose some of those deposits, and cause problems (due to the flowing deposits causing blockages in the oil flow). Over time both of these problems lesson, and then the true benefits of the synthetic set in. But you do have to pay some attention to what you are doing during the "conversion" (from dino oil to synthetic). Here's some advice for handling the conversion:

1) Consider an oil/engine cleaning product, before converting to synthetic. By first cleaning out some of the crud from the engine, the conversion to synthetic (synthetics work better in clean engines) is much safer. Amsoil makes an oil/engine flush for this purpose, as do most other companies. However, the product I'm currently using for this in our family cars is auto-RX, sold here: https://www.auto-rx.com/

BTW: I do NOT have any financial connection to the ARX company (except as a customer of theirs). In fact, I've got a financial disincentive to use this product, because I'm an Amsoil dealer (and therefore get dealer pricing on Amsoil's cleaning product). I just like the Auto-RX product better, because it does a good job of cleaning SLOWLY without the harshness/wear/damage caused by many of the cleaning products (including Amsoil's). i.e. ARX takes a little longer to work (follow the instructions on their site), but it eventually does a good job of cleaning, without the damage and harshness of many other engine cleaning products.

2) Consider using a really good oil filter. At the moment, I am currently using EaO oil filters from Amsoil. They are expensive, but their filtering ability seems to be just about top in the field (and that's not just Amsoil hype, people over on the "Bob Is the Oil Guy" forums have independently tested these things and found them to be top performing filters). While these filters are expensive (they can retail for $15 or more, depending upon make of car), their synthetic filter media does an amazing job of filtering without adversely hurting flow rate, and even can trap much more junk (then conventional paper filters) before filling up. So they last a LOT longer (I'm running my EaO filters between 10,000 and 20,000 miles each, and that's actually BELOW their longevity rating)! So like better oil, better filters pay for themselves in how long they last.

NOTE: I am an Amsoil dealer, so I'm not entirely unbiased here. However, I'm also a gassavers member, so I'll only recommend products I think really are worth it. And at the same time, I would be happy to help a fellow gassavers member with some Amsoil discounts (just send me a PM, if interested). In the case of Amsoil's (EaO) filters, I consider them "worth it" because they filter so much better (under 10 micron filtration, whereas many filters only do 30 microns, and some cheap ones not even that), and last so much longer (the synthetic filter media can hold a LOT more junk before filling up), that you make up for it both in better filtration (helps FE, and also helps you oil last longer), and a longer filter change interval (which means you have to replace the filter less often, and therefore you have to buy fewer filters).

3) Make your first oil change or two with synthetic shorter than it will eventually be (i.e. initially not much longer than the conventional oil change). This will give the synthetic time to clean up some of the existing mess (which may be lessoned, if you did an oil/engine clean step before this), and help the seals in the car get used to the synthetic oil. After the car is working well on synthetic (and you have good filtration), you can easily extend the oil change interval.

4) If the car starts leaking more oil (after switching to a synthetic), don't panic. As already mentioned, synthetic oil tends to flow easier, so it will often initially leak worse than conventional oil. But the good news is that a good synthetic often helps the seals to seal better. So often oil leaks get better over a few hundred to a few thousand miles of driving (on synthetic). Of course, if you are unlucky enough to not have the leaks subside on their own, it probably means your seals were already bad, and the gunk in the oil was "plugging the leak" as it were. In that case, you may have to have a mechanic replace the engine seals with new (undamaged) ones.

5) Remember, not all synthetics are made the same. While most synthetics are better than most conventional oils, there is still a HUGE difference in synthetic formulas. So it pays to hit the forums, and hear which synthetics are merely good, and which ones are excellent (and frequently there won't be a huge price difference between the two)!

6) And finally, remember that almost all cars leak at least some oil (some more than others). In general, this isn't much of a deal if you get an oil change every 3000 miles or so, as most cars won't leak enough during 3000 miles to be dangerously low on oil. So many people have gotten used to not checking their oil level (dip stick). But if you go long intervals (such as the 10000+ miles I put on my synthetic oil), you really do have to check your dip stick from time to time (and add "make up oil", as needed). Because you really do NOT want to let you oil level get too low, and therefore ruin your engine!!!

If you really want to know a lot about oil (both synthetic and conventional), check out the "Bob Is the Oil Guy" forums: https://www.bobistheoilguy.com/forums/ Those forums do for oil analysis, what gassavers.org does for fuel economy. So they are an excellent place to learn a LOT about oil.

However, FWIW my personal opinion is that Amsoil makes some of the best synthetic oils out there. I personally use (in both my CRX, and my wife's Civic) a mix of Amsoil 0w30 ( https://www.amsoil.com/storefront/sso.aspx ) and 0w20 ( https://www.amsoil.com/storefront/asm.aspx ) oils. OTOH if you want to be conservative, you could just go with all 0w30 (I like mixing the 0w20 and the 0w30 to give me a slightly cheaper, and slightly lighter and more fuel efficient oil mix).

NOTE: If interested in these products, check with me before buying from the above links. As already mentioned, I signed up for an Amsoil dealership. Which means that I not only get dealer pricing on the oil I buy, I can offer discounts (i.e. prices below those listed prices) to gassavers members. However, Amsoil rules are very strict against one dealer selling to another dealer's customer. So once you buy from another Amsoil dealer (and yes, the web site does count as a "dealer" for this purpose), I'm not allowed to sell you Amsoil products (or offer you discounts) even on future sales. So while I'd love to offer all gassavers members discounts, the Amsoil dealer rules prevent me from doing so if/when you are already "a customer of a different Amsoil dealer"...

Lol, the bitog invasion begins. Maybe all the bitogers should put it in their user info

I have seen many engines with over 300k miles that were immaculate inside as long as oil change intervals were kept around 4k miles. I have seen over 300 k on one 300ZX that was almost all highway miles with 7k oil changes.

1981 Nissan 200SX with 540k miles on the motor immaculate inside. Not even a stain when we did a valve adjustment.

Thats using non synthetics. If the oil has been neglected, just change it at the regular intervals and you can gradually clean up the gunk to a point. When the neglect is severe removing the gunk can be dangerous.

If it ain't broke why change?

Oil quality has increased greatly over the past 40 years. I wonder how much longer the old engines would have lasted with the current oils.

regards
gary