Product Reviewed: SAE 5W-30 Signature Series 100% Synthetic Motor Oil (ASL)
Current Rating: 4.97 out of 5 stars
Votes & Reviews: 1010 vote(s) and 1476 user reviews.
Reviewed by Shimmy: 
I've taken several engines apart but only engines that have run Amsoil and they only need coolant system work. Conventional oil precipitates out garbage and sludges up engines resulting in CLOGGED oil passages. If your switching from conventional, get the best protection you can get that has tons of positive history. Do your homework/research to understand ALL the costs involved. You will determine Amsoil is the best switch you can make for your vehicles.
Reviewed by Railrunner:
I have been using Amsoil products in my vehicles and motorized equipment for many years and relay on its quality. As a "gearhead", I know how important using quality motor oils and greases are to machinery. They are my first choice for lubrication fluids.
Reviewed by K-Mac:
I only use American AMSOIL in all my vehicles. For this one, I use it in my 2005 Honda Fit 1500cc..
Reviewed by K-Mac:
I only use American AMSOIL in all my vehicles. For this one, I use it in my 2016 Nissan Caravan NV350.
Reviewed by Jeff:
I run Amsoil oil and filter in my Yukon Denali 15,000 miles between changes. Just reset the change oil message at 7500. Doing this for years with several GMC Yukon's. At 250,000 plus miles no oil burn at all. Very impressed with not having to go under the car twice as much.
Reviewed by Ricky:
Awesome cold start protection, and anti-wear lube, simply the best
Reviewed by Mustang Larry:
So far all is good.
Reviewed by Mustang Larry:
Why is it when I change my oil does my mileage drop by 2mpg. For the first 400 miles 1 1/2 to 2 mpg less then it creeps back up.
Reviewed by Ron the Tyrolian:
I have relied on Amsoil products for years to protect my engines and it has done exactly that.
Reviewed by SamLac:
I started using AMSoil in the mid 80s while in Alaska. Cold extreme make lubrication very critical. At minus 40, most petroleum lubes won't even drip off the dip stick and when started cold you can hear every bearing in the engine as there is little or no lube flowing. No so with my AMSoil.
Reviewed by Jeff:
I've been running 5W30 Signature Series in my 2002 Tacoma since putting it on the road in 2016 with 116,000 miles on the engine. I have since had Oil Analyzers (Amsoil, Inc.) test three samples from the truck so far, and have yet to have the oil last more than 13K miles before being told it's time for it to be changed. So much for the 25,000 miles/1 year claim...
Reviewed by Grizz:
I have 2 vehicles that have had this oil in them (changed every 15,000mi) since I bought them new. They both have mileage approaching 250,000, and they run like BRAND NEW. My newest vehicle is a 2017 Subie Forester Turbo so it gets Signature 5W-30 every 10,000 miles, and I'm sure it will see 200k and beyond.
Reviewed by GF1563:
Love the extended oil change intervals and my fuel mileage increased slightly, which leads me to believe it must be lubricating everything very well.
Reviewed by Pat:
It's great year round hot or cold
Reviewed by Don:
Several years ago I switched to Amsoil in my GMC Yukon. I was very impressed with what the Signature Series 5w-30 Motor Oil looked like after the first oil change. With all the oils and products that Amsoil offers, I have since switched everything I own over to Amsoil. Even my lawnmowers.
Reviewed by dhgguy:
Used in my F150 exclusively. Excellent oil & filter.
Would not use anything else.
Reviewed by Ronv:
I have used Amsoil for 30 years and wouldn't think of using any other oil.
Reviewed by Mister nice:
Love that you don't have to change oil as offer as regular oil. Is is a little high. Hey but you get what you pay for.
Reviewed by Henry:
I use Amsoil exclusively
Reviewed by Jblev77:
#1 for 3.5L ecoboost
Reviewed by Ed:
I like being about to change oil at any time between 5-10k and not have to worry about weather or not the oil is doing it job !!!
Reviewed by RebelnOhio:
I have been using Amsoil for over 15 years and have never had a problem, it's a well proven product that I trust in all of my cars for work and for pleasure. I will will continue to use Amsoil and benefit from it's proven results! I own a Livery/Limo Service and I drive about 40-50K miles a year on various cars and I believe Amsoil is the best Oil for all of my vehicles. With the long 15k Mile change intervals it is a money saving gem and your engine benefits 100%. I recommend there products highly!
Reviewed by KENT:
I've used this brand and series in my Dodge Ram 4.7 v-8 since I acquired it at 90,000 miles. I've driven another 70,000 miles since and the engine is stronger than it's ever been! I expect to drive this truck until at least 300K miles because of the Amsoil Signagture Series Synthetic brand motor oil. I won't use anything else!
Reviewed by KK:
I use Amsoil on my SUV and love it!
Reviewed by Tom:
I use ansoil on all of my trucks, motorcycles, ATVs. This oil I use on 2017 Hemi 2500. It cannot be beat.
Reviewed by G:
Instant satisfaction, after the first start up i could already hear and feel things running smoother.
Reviewed by Redtundra8:
This is the best oil money can buy in my opinion. I use this in all my vehicles and have for the last 12 years. Love only having to change the oil once a year. I highly recommend this product.
Reviewed by Pat:
Bestboil products on the market by far. I run it in all my vehicles
Reviewed by Billy G:
I have used Amsoil products for many years in all of my vehicles and small engines. I have never had an issues. I recommend Amsoil even though it is not the cheapest but the delivery is very prompt.
Reviewed by Wingsprnt:
Not sure about the oW-20 weight here in Florida, but that is what Honda calls for.
Reviewed by Greg:
Always met my expectations.
Reviewed by MatsB:
Using Amsoil in all of my family's cars. Using Signature series in cars that drive over 12,000 miles per year, and XL series in cars that drive less than 12,000
miles.
Sent a 27,000 mile sample for testing to a independent lab, and they recommended 30,000 miles next time based on the excellent results.
Also using Amsoil in all lawn equipment and for a standby generator.
Reviewed by
Robert Long:
Great product gives better fuel mileage and cleaner oil after changes
Reviewed by Tim:
I've been using Amsoil since the 1980s in everything with an engine. And have bragged about it's benefits to anyone who'd listen.
Reviewed by Rob:
I get better mileage with Amsoil
I run my 4x4 very hard and Amsoil is doing a great job of keeping it running strong
Reviewed by Elvis of Aragorn:
My 2004 Silverado (5.3L V8) has had a steady diet of Amsoil since its second oil change. I have stuck to the 10,000 mile interval, using Amsoil Ea filters & Signature Oil. She's about to roll over the 200,000 mile mark, and I have had no engine issues. I use Amsoil Signature Synthetic Oil in all of my vehicles, and plan on keeping it that way.
Reviewed by Pinto:
I'm city driving in a 4x4 Ford van and after my last oil change the oil was still in great condition after 15,000 miles. just used the cleaning solution so lets see how this improves engine longevity. really happy with all th products I have received.
Reviewed by S2kadi:
I use Amsoil Signature Series in both of my cars that are susceptible to burning oil. The 10W30 goes into my Honda S2000 and works great! Amsoil is the only oil I use in my motors and gearboxes, after trying out several different brands, I have found their quality to be of the best.
Reviewed by pro4100:
I use it in my Subie Forester and my silverado 1500. no problems ever!
Reviewed by Quick charge
water:
Yeah like to 25,000 my old changed
Reviewed by Beast:
I will never use conventional again. 10K mile Oil changes, or once a year. You cant beat the quality and value of this product. No dealer or mechanic can ever persuade my to change every 3k miles again!. Get you some!
Reviewed by Ber:
Better mpg and engine protection
Reviewed by ScoobyVTEC:
Bought Amsoil for all of my cars so I wouldn't have to change the oil so frequently
and for the protection it gives all of the internal moving parts. I've noticed an increase in MPG and smoothness when I drive.
2017 Civic Type R
2012 Pilot Touring AWD
1998 Civic EX
Reviewed by Mark:
Started using in my 08 Subaru saw better gas milage the car ran smoother so I began to change ever gas engines l own to amsoil. Couldn't ask for a better product !!!
Reviewed by Jim 38:
I've used amsoll since probably 1990 in my mowers my pickups my tractors. I swear by the signature series it's done wonders for me and Increased gas mileage you have to try it for yourself to see the picture
Reviewed by BC:
I've been running this oil in my Mazda for a few years now and even after a full oil change interval and heat a rotary produces it still looks very clean
Reviewed by Adam A:
I have started to use this product on my 99 town car a few months ago and I have already seen a difference in just how to engine stays cooler and is able to drive a lot smoother. I would definitely recommend this to anyone wanting a better lubricant for their engine and to have better performance out of anything they have.
Reviewed by Carp:
Other oils just wouldn't hold up. Would burn off and be black by 1,000 miles. I have work trucks, daily drivers, and toys. Work as a technician and never seen oil drain clean after a normal service. Except Amsoil after 10k looks good as new.
Reviewed by Mackjash:
Amsoil have provided my street and race motorcycles with excellent protection. Recently tore down my old race bike which has 30,000 miles on it of which 7000 are track use. Measuring all major parts and the engine shows no wear, factory cross hatch is highly visible in the cylinders. Great product!
Reviewed by jmcamp:
I use all Amsoil products in all my vehicles and yard equipment. I even have them change it on my Volvo XC60 that is under warranty, where they recommend and use another product. I always tell them to use the Amsoil oil I bring instead.
Reviewed by Trigger:
AMS Oil's Signature Series oil has been the best oil I've tried so far. It has been cleaner from oil change to oil change compared to synthetic oils from NAPA, Valvoline, Royal Purple, Mobile One, and Castrol, and I've seen fewer metal shavings comparatively to many of the aforementioned oils. Royal Purple was the only comparable oil heat wise but it's generally dirtier between changes and more expensive.
Reviewed by Mac:
I have a 1998 Chevy Suburban with 230k miles. Its whole life has been 100% Signature AmsOil. The motor still has 155-160 compression in all cylinders. It still gets "like new" gas mileage. It still pulls trailers like they aren't there. Simply impressive.
Oil changes every 10k miles (since I pull trailers). Compared to conventional oil every 5k, it is breakeven in total cost - (after discount from AmsOil). PLUS - I only change the oil 3x per year instead of 6x. In fact, I love the fact I can change oil in fall and not again until spring. Skip right through winter.
AmsOil products are worth every penny.
Reviewed by trey512001:
great product and now a longer interval change at a fair price. what else could you want !
Reviewed by Andy:
I put this in my 1996 Chevy K1500 with a 5.7. Slight tapping on startup disappeared, and i gained about half a mile per gallon. Not bad for a motor with 200k on it. Always happy with all Amsoil products, it's all I run.
Reviewed by Anthony:
Simply the best bang for the buck. I have oil analysis to back it up.
Reviewed by Carb:
Hands down the best oil on the market! Will never go back to the other stuff.
Reviewed by Postman:
Use it in all my vehicles. I beleive ya the only way to go
Reviewed by Postman:
Use it in all my vehicles. I beleive ya the only way to go
Reviewed by
TAK:
Been using Amsoil for 20 years and never had any engine problems.
Reviewed by TNMrK:
I have used this oil in both my personal vehicles 2012 Silverado and 2011 BMW and they run super smooth with this oil. I will not run anything else. When I work on a customer engine I put Amsoil in and recommend it for life.
Reviewed by Gordy:
I always use Amsoil in my vehicles and have had outstanding performance from it
Reviewed by Jagger:
I can only speak honestly and being that I just acquired the vehicle I changed the oil and transmission fluid recently to Amsoil. Both products seem fine but I cannot really say that they made any noticeable improvement in mileage or smoothness or anything else however I'm hoping they do provide the protection I'm looking for and continue to keep my vehicle running great for many years to come.
Reviewed by Railroder:
I started using aimsoil in my car a year or so after I bought it. I drive a lot, 400,000 + miles on my car at this time and still going! Know I use aimsoil in my tractor also.
Reviewed by GreatOil:
Only oil I have used in over 45 years of changing oil, That after 18000 miles still has plenty of protection left in the oil. Got to use a good quality filter as well, but this oil is awesome
Reviewed by Fast1LE:
Pay a little more and get a whole lot. I use Amsoil in my transmission, rear diff and engine. World of difference. I track my car as well and believe me I'm hard on my driveline. Gears, transmission and engine perform at optimum levels with Amsoil and you are protected. If it's used in racecars it's for a reason.
Reviewed by Kyle:
Great product, buying again.
Reviewed by Canonball:
This oil has made a noticeable difference in my hemi. It's made the engine quieter and given me better overall gas mileage. You can't go wrong with the right oil.
Reviewed by Erik:
I run amsoil in every motorized vehicle I own...very happy with all products
Reviewed by Dan:
I started using Amsoil several years ago in my 2-stroke YZ125 and was very impressed. Back then I was rather unfamiliar with Amsoil so I started doing some research on Amsoil and other competitor brands, because I only wanted to run the best lubricants in my equipment. What my research uncovered for me is what I now believe to be so great about Amsoil. Amsoil provides plenty of literature from third-party testing that truly separates their products from the rest of the field. Other brands will only tell you what they want you to hear, but what is great about these testings is that we as customers can see for ourselves side-by-side test results, and the results speak for themselves. In these tests Amsoil's products are put through the ultimate rigors and unbelievably harsh conditions and STILL protect against breakdown and wear. The one thing about Amsoil is you won't see expensive ads on TV about what the company's oil "can or will do" for your engine like the "Big brands",however, with Amsoil you can read for yourself from unbiased third-party test results that PROVE Amsoil's greatness over competitor brands. As you can tell I am absolutely sold on Amsoil now days and run it in all of my vehicles even my lawnmower and snowblower. With harsh MN winters I need the best oil to protect with cold start ups. I would encourage everyone individual who is new to Amsoil, or even a long time user, to take a look at some of the testing that has been done on their products. Read the results! If you're still not sold on Amsoil I'm not sure what else to tell you.
Reviewed by Andy-Boy:
Long oil life, keeps me going longer without having to do oil changes, engine sounds " heathy " less valve noice.
Reviewed by Doug:
Love all the Amsoil products. They've kept my 10-20 yr old engines clean and functional in severe heat.
Reviewed by None:
I've been using Amsoil in my vehicles for over 10 years now and in my opinion it is the best and less expensive in the long run. Less oil changes, less maintenance and better gas mileage. Over 280,000 miles on my 2004 truck and does not use a drop of oil between changes. Would like to see more in and out oil change businesses carry Amsoil.
Reviewed by Desertrunner:
This stuff is well worth it. Noticed the first oil change that my truck runs smoother and quieter(Toyota tick). Waiting to see the oil analysis when it's time.
Reviewed by Scott:
Been using AMSOIL products now for approx 15 years. I use it in all my vehicles. I use change my oil every 10,000 miles with Amsoil filter. Never had an issue with Amsoil. Highly recommended,
Reviewed by Perk:
When you buy something you expect it to do the job it was made for. AMSOIL does that for me. I became an Amsoil fan around 2001 when my Chevy pickup was first sold to a farmer here in Pittsburg. I was living in Alabama at the time and I had put AMSOIL in both my vehicles and was very pleased with the performance improvements i.e. mileage, performance, etc.
We moved to Texas and my wife
said I needed a pickup. Every Texan man needs a pickup, so we bought a 2001Chevy Silverado with 99,000 miles on it. It ran like a new truck. I immediately put AMSOIL in it and now with 132,000 miles on it it still runs like a new truck. I haven't had to do any maintenance on it other than maintaining fluids, tires, wiper blades and the like. And i expect it to continue performing like that as long as I have the vehicle. I will never use any product other than AMSOIL lubricants in my vehicles. I also use them in my Toro Zero turn riding mower.
Reviewed by Full out:
I have been running amsoil For over a year now. Naturally aspirated v6 in a 2011 Ford Explorer and TwinTurbo V6 ford F150.
We know how turbo charged engines can generate heat and breakdown oils much quicker
I really like the extended drain intervals and even with almost 13,000 miles on my F150 the oil that came out was still very thick.
probably could've gone several thousand miles more.
Usually with that kind of mileage and that kind of abuse oil comes out the consistency of water.
I'm not easy on my vehicles either And tow from time to time.
I just purchased oil, transmission oil, and filter for my Honda TRX 450 Atv.
You have a customer for life!!
Reviewed by Bam Bam:
This company is #1 for oil and have a lot more products the oils I use work well I have taken motors apart in past and they are clean and no damage good products
Reviewed by Bman:
I run everything amsoil even snowblower I own a boat a Jeep Wrangler Chevy Silverado rmz450 dirt bike a hayabusa and other small engine equipment all motors run perfect nothing better enough said!
Reviewed by Shane:
Ever since being introduced to Amsoil, it's all I use. I've put it toe-to-toe with friends using other brands of oil, and they've eventually seen the light and moved over to using Amsoil as well. Never disappoints.
Reviewed by Ant:
The only reason I'm not giving it 5 stars is because I have a 2002 Nissan pathfinder with 240,000 miles leaks a lil oil but with Amsoil 5w-30 signature series and when I use it it leaks even more...think about your high mileage customer. I aslo have a Infiniti QX56 2008 with 132,000 with 5zw-30 signature Series no leaks at all and just did the transmission fluid ATF, transfer case and front a rear diff with the server gear fluid and shifts are so smooth rides like a dream 5 stars on that! But for my 02 Pathfinder had to switch back to a conventional high mileage oil with seal conditioner.
Reviewed by Josh:
I put it in my vehicles and change it when needed
Reviewed by StorminNorman:
Amsoil is Great. I've used it for 20 years. It's in everything I own. Why would you use any other oil?
Reviewed by ME:
I buy this product once a year along with the oil filter. I have a car that is 16 years old and it runs great. Have always used this oil and filters.
Reviewed by Rob:
I use this oil in all my vehicles. It works day in and day out
Reviewed by Little George:
When you have some get in the truck & ask why it runs so well it opens the door
Reviewed by Ryan:
Works great! Have used it in every machine I own for the last 13 years. I have Never once have had an engine issue on any vehicle I own since switching to Amsoil.
Reviewed by Jbush0202:
Works better don't burn as fast in my truck that eat gas and oil as snacks
Reviewed by Zen:
I do my oil changes annually and find that my vehicle runs smooth all year long. I've used other synthetics and have found from my experience that my car responds best to amsoil especially as I approach 20000km mark at the end of the year.
Reviewed by Faisal:
Awesome product. Use it on both my car's.
Reviewed by John:
The peace of mind knowing the best oil I can get is in the motor is worth it.
Reviewed by Dejohn98:
I feel a lot safer taking it to redline knowing that I've got good protection in those turbochargers I'll never use anything else
Reviewed by STP:
I first tried this in my personal daily driver and liked it so much I'm now running this oil in three cars. Also running the racing oil, transmission fluid and gear oil in my race car!
Reviewed by Medic Mike:
I have used AmsOil oil since 2006 i trucks, performance cars and SUV's. I love the extended drain intervals with AmsOil oil filters. When I replaced an oil pan gasket the shop was surprised how clean the oil pan was with 100,000+ miles on a 2003 Escape. Be advised when I switched to AmsOil in the 2003 Escape it had 80,000 miles on it and I used the AmsOil flush as well before first fill with AmsOil. The combination of Also oil and gear lubricants kept the 2003 Escape getting the sticker MPG new or better. I have so used this with a 2007 350Z and a 2006 Dodge 1500 5.7 Hemi with bypass filter set up.
Reviewed by Jayme:
I've been using Amsoil for over 15 years and Hands down its the best
I use Amsoils in everything that requires oil
It's works !!!
Reviewed by Dennis the driver:
Amsoil has saved an engine when lost oil pressure and had to continue driving 200 miles. had to replace bearings but crank shaft was not damaged. I have increased gas milage.
Reviewed by John:
Superior products used in all my vehicles
Reviewed by LH:
All products that I've used from AMSOIL are excellent! I would not use anything else!
Reviewed by JR:
Excellent product. Miles 175000+ change oil & filter once a YEAR
Reviewed by SuperSuzy:
I've been a faithful customer and user of Amsoil products for almost 10 years now.
I can say with out any doubt that it has been the single best product I have ever used in my automobile.
My 2002 Suzuki XL-7 has been running on Signature Series 5W30 for 9 years straight and my motor feels like is hasn't lost a shred of power.
As an automobile owner who takes absolute meticulous care of his machine, there is simply no substitute for Amsoil.
Canada
United States
I would buy this product and use it in every car I own
I own 2003 s2000 that I recently rebuilt the cylinder head on. Prior to the rebuild the car was turboed for a decent amount of time. The car currently sits around 112k miles at the moment after the rebuild. The car has been running Amsoil signature series for most of its life. When I inspected the camshaft, cylinder walls, etc during the rebuild the car showed absolutely no sign of wear anywhere and this is after being turboed and ran hard for a decent amount of time. I moved back to 10w30 signature series after the rebuild but still great stuff.