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 Butch: 
I have been using Amsoil signature series 5w-30 synthetic oil about 3 years and am very happy with it. I change my oil just once a year now compared to 2-3 times in the past. My engine runs great and in the long run it costs me less, no engine repairs or tune-ups other than normal maintenance. This is great considering I tow a 20 ft boat and put on at least a thousand miles a year just towing. I am very happy with this product and highly recommend it.
Reviewed by Rainman0069:
Have been using Signature Series oil for years in all my vehicles, past and present. Long life and excellent protection. 2008 G8 GT 6.0L used Signature Series since day one, 120K later, engine still like new.
Reviewed by Mickie:
Took a long hard look at using Synthetic Motor Oil Products , back in the middle 90s, and have spent over 30 years in the Air Force I knew what synthetics were about.. And now I only had to figure out what were the best ones to use in my Cars and Trucks..
After about 8 mos of researching Fiction and Fact about Synthetic products, ( They are not all the same, especially the Base Oil ) I settled on AMSOIL for my Oil and Especially Filter Needs .. I feel that the Most important part of using Synthetic products is the OIL Filter, and its Specifications.. Many Filter Manufactures are reluctant to give information on their filters makeup. But you can find it if you dig deep enough and Understand the Testing regime used to make comparisons. AMSOIL has been around longer than anyone
when it comes to synthetic oil for your vehicles.. Just go with the Best.
Reviewed by Jeremy:
Quick delivery couldn't ask for a better way to buy oil!
Reviewed by Chris:
So far, so good. Oil levels have been maintained with the usual discoloration. I'm waiting for my next oil change in order to perform an oil analysis. Then I shall know the truth of Amsoil's claims for myself. But, for the time being, I am impressed.
Reviewed by jc:
I do like the ams products. Its definitally one of the best oils on the market. Is rate it as good or better than mobile 1 which says alot. Ive tried the racing oil as well and it is awesome.
Reviewed by Jose:
I have a 2015 chevy cruze and I change the oil every 20,000 to 25,000 miles. I use to have a 2011 chevy cruze before and i changed the oil between 20,000 to 25,000 miles. The engine runs cooler never had a problem running with this oil. I recommend everyone to switch to this oil. Buy!!!
Reviewed by Hoosier Cruiser:
I have been using Amsoil signature oil in my vehicles for the past year and have been able to cut the cost of oil changes by approximately 50% ! I am sold in Amsoil
Reviewed by Mitch:
I have used signature 5w-30 as my all-around oil in everything I own. Cars , trucks, lawn mowers, snow thrower and generator. Since 1994 I've never had an oil related issue and it makes oil changes simple , just grab the Signature 5-30!
Reviewed by Storm Petrol:
Our 1999 Odyssey wouldn't start after our son pulled off the highway to tighten down the tarp on the trailer he was towing. By the time the tow truck driver got there, it did start. The driver said he would follow for a time to insure the van kept going before he went on.
The engine temperature immediately jumped into the red zone. An inspection showed that the rusted hose clamp at the bottom of the radiator had given up--there was nothing in the cooling system!
After a tow to the shop, with the addition of a new clamp and coolant, the vehicle started.
1300 miles later, we heard about this from or second son and our mechanic checked for codes. The sensor had recorded 395F at the time of this incident!
I immediately replaced the crank oil for 5 new quarts of Signature Series 5W-30.
The old stuff, which only had a few thousand miles on it, smelled just slightly burned.
Our mechanic said he would typically expect the engine to be toast, with vital components even melted! Yet, although we don't know the actual condition of the rings, pistons and cylinder walls, the car is running well, with no misses or apparent loss of power.
The only reason we can all think of for survival of the engine is the Amsoil, with its superior cooling qualities.
It gets the credit for the fact that the engine is still running at all!
Reviewed by Steve:
Is this product and love the 25,000 mile oil change!
Reviewed by TINY61:
THIS IS ONLY COMMON SENSE. IF YOU KEEP ONLY THE BEST LUBRICANTS IN YOUR EQUIPMENT IT WILL GIVE YOU ITS' BEST PERFORMANCE. AS THE COST OF MODERN VEHICLES IS SO PROHIBITIVE IT MAKES GOOD SENSE TO USE THE BEST. MY VEHICLES FROM MY 1978 THROUGH MY 2008 ALL PREFORM BETTER WITH AMSOIL.
Reviewed by Huffy:
I use this in my cars from brand new!!
Reviewed by Bob:
Have used Your products for over 20 years in all my vehicles
Reviewed by Dennis:
the best oil money can buy, don't take my word, try it for your self.
Reviewed by T-Lou:
Like the longevity.
Reviewed by Redman:
I've been using AMSOIL for going on three years and its nice knowing that my 12 year old truck wither 175,000 miles and is protected by the best synthetic oil on the market and continues to run great. Once a year old changes, with a mid year oil filter is easy maintenance. I recommend AMSOIL products to all the people I talk to who are being thrifty with their older vehicles. Compared to the costs of simple oil changes at a garage. AMSOIL products that I have tried have stood up to the advertising they offer, and its rare to get exactly what you read about these days.
Reviewed by Jon:
I am a part time collage student getting my certification in auto mechanics, my engine seems to run quieter and the mileage has gone up maybe 1 or 2 mile.
Reviewed by Annie:
I grew up in a family where good oil was the name of the game to keep your vehicle going for many miles. Just when you think the car is on it's last leg it will keep running and I believe it is due to the success of Amsoil products being used. If you are looking to only have to change your oil 2 times a year, once in the spring and once in the fall. I recommend you to buy this product. I have had great success with my vehicles and with Amsoils services.
Reviewed by This is a stupid question:
I bought it, it came, I used it.
Reviewed by Kyle O.:
Excellent used oil analysis after 10k miles - better than Royal Purple. Just remember to top off. The wider opening helped me give a controlled pour. Everything went in.
Reviewed by traderdollar:
Put it in my 125K, 2005 Lexus RX 330, along with the Amsoil filter. Every thing fine so far. I'm looking forward to what the oil looks like in 10K miles. Actually, looks probably don't mean much. Would need to test.
Reviewed by WVJAY:
I have been using the Signature Series for many years in my 2002 Olds Bravada. I purchased it new and have always used synthetic oil. The main reason I use Amsoil Sig series is the long intervals. When a person can change their oil once a year vs 4 times a year it was a no brainer. Once a year is much less work for me and it's WAY CHEAPER!!! I highly recommend using Amsoil and I believe when you try it u will be extremely impressed.
Reviewed by Aguaman:
I use this oil in both my car and truck. I like how I can schedule my oil changes during the nice weather seasons here in Idaho. I been changing the oil once a year without any issues. The oil always looks very clean and clear at changes.
Reviewed by mttrsn1:
This is the Staple in any engines life! Have been using this Amsoil product for 16 years now in many different vehicles. Use Amsoil products in all my equipment, SUV's, cars, lawn tractors and mowers, from the motor oil to the transmission fluid to gear lube/differential. Never have to worry about or even think about if you have the best protection possible. Engines run very clean, smoother, quieter, and noticeably better fuel mileage. Outstanding performance!!!!
Reviewed by Tony:
I use Amsoil in all of my engines and I have never had any issues. I get great gas mileage and when the oil is changed, it doesn't look much darker than when it went in. I am a preference type person, and I prefer nothing else but Amsoil. All of their products are the best, first class!
Reviewed by David.:
The typical cold engine slap noise is gone. Oil pressure stays up after engine warms up and fuel mileage continues to climb. Do not hesitate to buy this oil. Mobil 1 isn't close!
Reviewed by Mark:
A number of years ago I learned that synthetic oil was superior to conventional oil. Shortly thereafter I tried amsoil and discovered that amsoil was superior to other synthetic oils. This became evident when I started traveling on 2250 mile trips on a fairly regular basis. Other synthetics
needed a quart on the trip. Amsoil, none.
I researched the issue and a competitor alleged that the difference was based upon Amsoil's use of too much of a certain additive and that that additive would ruin a catalytic converter. I have put over 150,000 miles on three different vehicles and none ever needed a catalytic converter or oxygen sensor.
Reviewed by Strick:
I have used this product for about eight years now and my car is 13 years old and still going strong/
Reviewed by Jmlo96:
I run this oil in my turbocharged Chevy Cruze. It is clear in the numerous tests that Amsoil makes a superior oil. I was sold on Amsoil when I had a rough manual transmission shift, and the Amsoil fluid made it totally disappear.
Reviewed by Justin:
Awesome oil. I have a 04 Dakota 4.7 with the dreaded lifter knock and after trying a few different things. I was recommended to try some amsoil products and I will never go back to anything else. Gave my motor a good feel and the tapping is very minimal, you can barely hear it in and it goes away after a second or two. Will always use amsoil products.
Reviewed by MrBigWay:
I have used Amsoi in all my vehicles sense it first came out, I notices a increase in fuel economy and performance.
I put it in the motor, Transmission and rear end of my race car and increased my ET by .5 seconds which is amazing
I also use it in my semi truck with the same results in mileage and performance
Reviewed by Brando:
The wear protection is phenomenonal, the performance improvements are noticeable and the extended drain intervals are what make Amsoil my favorite product. I currently run this oil in a half ton (V8) and SUV (V8) which put between 30000-40000 miles a year each.
Reviewed by Kilted One:
Our 2015 GMC requires GM spec oil which Amsoil more than meets. Being a bit old school on oil changes I like the margin of a high quality synthetic because modern engines are under much higher stresses and heat than when I started driving and wrenching.
Reviewed by Robb:
I have used Amsoil Signature since my vehicles were new. 2 of them have over 200,000 miles and the 3rd has over a 100,000. I have shortened drain ontervals to 12,000 miles and leak no oil in-between changes.
Reviewed by SHUZAAM:
I use this product in my 2007 Chevrolet Cobalt.
When I first purchased my vehicle, it was absolutely not taken care of.
Along with a multitude of other mechanical repairs, I changed the oil that was in it, with Amsoil signature series motor oil,
Amsoil automatic transmission oil, and
brake fluid from Amsoil.
Boy, I tell ya. When you take care of your vehicles and use Amsoil motor oil and products, the performance of your motor gets a boost.
I've noticed it runs way better, and lasts way longer.
It keeps my engine healthy, and I'm always sharing the experience with others.
I also used the European synthetic on my girlfriends beetle, which was production condensation of oil on and around the oil cap and fill hole.
The engine was burning it up, and there was a leak that was found by a rinky dink shop.
I
put in some Amsoil hoping it would fix the issue.
Of course, it always proves itself.
Healed up all the gaskets and stopped the leak.
She didn't have to fill up every 2 weeks anymore, and her engine is running even better.
BUY AMSOIL PRODUCTS PEOPLE
Reviewed by Prius:
Use this in my Prius Hybrid and gained 1.3 miles per gallon. The added protection of Amsoil in my engine gives me a great peace of mind.
Reviewed by Larwel:
Use it in my Corvette C6
Reviewed by Doug:
Not much to say, really. I'm pretty sure the main ingredient is awesome sauce, though. I won't put anything else in any of my ICE-powered vehicles. If Amsoil could make electrons, you know e-cars would go faster.
Reviewed by HHR Man:
I have used Amsoil for years in several different vehicles and have found the product to be superior to the other products that are found in stores. I have had comments about how well my vehicles have run while using your product.
Reviewed by Moto Man:
I use Amsoil in the car, my motorcycle, and in any other engine I may possess. I am not brand loyal except when I find a product that is so superior that no comparison exists.
Reviewed by Nick:
My dad started using Amsoil in the 1980's and when I started driving in he mid 90's I started using it too. Never had any issues and I always beat on my vehicles. Excellent oil.
Reviewed by J.P.:
i have used amsoil in my 2002 chevy avalanche with a 5.3 liter engine. i have 140,000 miles on the engine and oil consumption is less than a pint every 8,000 miles. i also use amsoil in my wifes 2003 chevy trailblazer, it has 121,000 miles and does not use any oil. i go 8,000 miles between oil changes.
i also use amsoil synthhetic transmission fluid in both vechiles.
Reviewed by bgdv1:
I run the 5W-30 in my Tacoma, my wifes Legacy and our sons 4Runner. I also run all Amsoil oils in our 2 Harley Davidson motorcycles.
Reviewed by brian:
after 1 year oil is in better shape in color and overall viscosity that conventional oil i use the recommended amsoil filter with cold winters and hot summers pulling a boat of 5000 saves me money only changing once a year instead of 3 with regular oil
Reviewed by Tim1457:
I started using Amsoil in 2011. I talked to several people at work that used Amsoil products and we're very satisfied with it. I got a dealer at work to order the Signature Series for my Tundra. Well, 5 years later, I'm still using it and still loving it. I've also used the transmission fluid and products for my ATV. I'm sold on Amsoil.
Reviewed by Ewan:
Title says it all. I bought this for my first oil change on my 2015 Ford Focus ST. I'm now on my second oil change using the same product. My engine oil temps run consistently 15-20 degrees cooler than before. Will never go back to another brand again.
Reviewed by trigama3:
Retired my 1994 Toyota xtra cab 4 cyl, 5spd pickup in 2014 with 267,000miles.
Started using Amsoil around 70,000 miles because I got tired of changing oil every month. Never burned oil.
Truck had a full load with it in the entire time I used it. Worked that motor hard.
Reviewed by Neil:
I use this in my 08 Pontiac G8 it works good I like better then going to the auto parts oil
Reviewed by KeniceThe Menice:
I have ran Amsoil in my diesel truck since 2008 and converted my girlfriends gas truck over about two years ago. I like reading about the testing done comparing Amsoil products to other companies products. I feel like Im using the best oil out there. Soon my 70 Chevelle will run Amsoil too.
Reviewed by Joshua:
I works well in my dakota and have used only amsoil in my ruck for the last 100k I have @190k on it now
Reviewed by DJ cars my passion and hobby:
use amsoil in my 2000 corvette (135,000 mi), 2002 325 bmw (140,000 mi) and my 1956 chevy 210 with a 355 stroker hardly any miles but really like the Z-rod oil. Been using amsoil for 8-10 years and to date no engine problems. will continue to use their product till I'm grounded from owning a vehicle.
Reviewed by Brand:
I've tried other oils, this by far is the best. Less consumption noticed, stays cleaner longer. There is a difference, I've tried them all, in motorcycles and trucks, this is by far the best in my opinion!
Reviewed by Tedd:
I've been using Amsoil products for years so I am aware of the guilty and value, but what always surprise me, and I don't why by now, is the fact that they are usual at my door in 1 or 2 days. Fantastic shipping for me. I appreciate that greatly. Thank You Amsoil😊👍
Reviewed by Dick:
I have used this in my Toyota pick-up for 11years and the engine is like new.
Reviewed by JW:
I have been using this oil for over 20 years in all my vehicles. It is by far the best motor oil I have ever used. I started using in my 1996 Chevy pickup. The garage had to replace an intake manifold gasket. They ask me if I had cleaned the engine before bringing it in. I said no, they said the engine looked brand new inside, it had absolutely no carbon build up. That was amazing since the truck had 158,000 miles on it. You can't go wrong by using this oil.
Reviewed by Duck Killer:
I ran this oil on the 15,000 mile program because I'm on the gas pretty heavy at times. The first cycle went well, but the next cycle I pulled my trailer a lot and the oil was history at 6,000. Truck also had lifter tick at start up when motor was already at running temp. Went back to conventional oil and lifter tick was gone.
Reviewed by Vladimir:
I come from the old school that good quality oil is always cheaper than rebuilds and parts replacement. I have been using Amsoil products for over 20 years and the results have been outstanding. They provide the best protection against wear keeping the powertrain in outstanding clean and excellent conditions for many, many trouble free miles.
Reviewed by Skip:
I've been using Signature series 5w-30 for over twenty years and will use no-other because it simply continues to be the best available synthetic motor oil on the market.
The mechanic I use puts it into my engine, transmission, radiator, and differential.
I have a total of over one hundred thousand miles of trouble free driving on my vehicles.
Reviewed by Jerry:
I use AMSOIL like aircraft owners use engine oil on their planes. Auto owners change oil and filter every 3,000 miles or 3 months witch ever come 1st. With AMSOIL I change oil every 10,000 miles and filters every 5,000 miles. Easy to remember and cheaper than 3,000 mile or 3 months. Tell your wife not to nag you about oil change until she nears that 10,000 mile mark.
Reviewed by None:
I have used Amsoil for 20+ years. I collect classic Mustangs and only the very best products are used on them. I also use Amsoil in my 2006 Silverado. My wife just bought a 2016 Buick and Amsoil will go in at its first oil change. I've never had a lubrication mechanical failure .
Reviewed by Huffy:
I use this in my cars from brand new!!
Reviewed by Cliff:
I have used Amsoil for several years in just about all of my vehicles. The only one I do not use this oil in is an old 69 VW that leaks from time to time. For any other vehicle, old or new, I highly recommend Amsoil Sigature Series. I save about $100 a year per vehicle on oil changes. Once a year oil changes save a lot of time too. I've never had any issues mechanically with the extended oil changes.
Reviewed by Dan:
I have always used high quality synthetic oils in all of my cars (daily drivers) because I believe it pays off in reduced engine wear. The Amsoil Signature Series is on par, if not a notch above the other oils I have used in terms of performance.
What sets this apart from the competitors is the extended drain interval. Since my car is turbocharged, I follow the heavy duty recommendations (15k) with a filter change per Chevy's instructions (7.5k). This saves me time (cartridge filter takes 2 minutes) and money versus an oil with a standard drain interval. It would save even more in a vehicle that
can follow the 25k drain. Even at the end of the 15k, I don't notice any decrease in performance, but I change it anyway.
Reviewed by Rascal1101:
I have been using Amsoil products over 20 years now and have been pleased with all the performance and durability aspects.
Have used the Signature blend oils in many cars for the extended drain intervals and have never experienced any failure, wear or usage problems.... period.
Why would I use anything else?
Reviewed by Mxmantc87:
I've used amsoil in all of my dirt bikes for 10 plus years every new top end build the engines have been spotless. I just recently started using amsoil in my vehicles and so far I'm blown away on how good the oil is even on changing its not black and thick like other oils I have used. I change my oil in my cars every 15 thousand miles with this oil it's good up till 25k but I just do it out of peace of mind. If you have never used amsoil I recommend you give it a shot. I'll never use any other oil in my vehicles or dirt bikes except amsoil 😀👍
Reviewed by WOMPUS:
I use the 5W30 in 2 of my cars, 1 Chevy truck, and 2 Street Rods.
In fact I use Amsoil in everything from my air compressors to my boats.
Never thought of using any oil but Amsoil since the mid 70's.
I'm a walking advertisement for Amsoil... great oil, in fact I just turned 325,000 miles on my motorcycle, if that isn't proof of Amsoil then I don't know what is!
Reviewed by Tim:
I am fully satisfied with my product especially the fast delivery
Reviewed by Scott:
I use this oil in my 2012 Nissan Rogue and my wife's 2011 Nissan Juke (Has a Turbocharger in it). I love being able to go 15,000 miles/1yr to do an oil change. Saves me money and I don't have to make time 3-4 times a year to make an appointment for an oil change. It may cost more upfront for the oil and filter but it is cheaper by the end. Figure at least $20-30 per basic oil change multiply that by 4 times a year, you just spent $80-120 for 4 oil changes in that one year, for a basic oil change at every 3,000 miles.
If you get this Signature Series and a Ea filter you can go 15,000 miles. You get and extra 3,000 miles or one less oil change. You just saves money right there.
If your vehicle has a Turbocharger in it, you must use Signature Series. The engines get way to hot for the basic cheap oil.
Even if you get free oil changes from a dealership, they use basic or
synthetic blend oil, and most likely and unknown or cheap oil filter. Do you want to put cheap stuff in your vehicle? I don't.
Reviewed by Ryan:
I've used the Signature Series 5W-30 in my Nissan Titan for over eight years and have never had a single oil-related issue, even when pushing my truck to the limits.
Reviewed by Satisfied:
I've used Amsoil products now for about twelve years.
After a year, the drain oil is not much darker than it was when it went in.
I put about 1000 miles per month on my truck (2014 Xterra).
Previously, I drove a 2001 4Runner similar miles.
Reviewed by PM:
Your product have become overpriced and shipping prices are out of control, can't imagine if I wasn't A preferred paying customer...
Reviewed by M.L.:
I use this oil in my 2011 and 2005 Silverados. Never had any trouble with 120,000+ miles on both of them.
Reviewed by Lucky:
I use amsoil in everything I own bikes quads vehicles ect. I use this in my 2012 Silverado trucks seams to preform better with this rather than the mobile one I was using before
Reviewed by Derek:
As long as Amsoil is in business I will not buy another oil.
Canada
United States
Great product
A little pricey but after researching the product, it's the best in the industry. Kinda get what you pay for.