Product Reviewed: SAE 5W-20 Signature Series 100% Synthetic Motor Oil (ALM)
Current Rating: 4.95 out of 5 stars
Votes & Reviews: 528 vote(s) and 1218 user reviews.
Reviewed by James: 
Been using 0w-20 and 5w-20 in our 2007 mazda 3s since it was brand new. After 107,000 mostly city miles and 10 years Engine still runs like new and have had zero leaks and still doesn't burn a drop of oil between yearly changes.
Use Amsoil and create less waste and save money and problems by changing your oil less.
Reviewed by Izzy:
I've been using Amsoil for most of the past two decades. It's the only oil trust to protect my engines and now my firearms. They have never let me down and have earned my loyalty.
Reviewed by Dino:
Been using this oil for awhile now like all amsoil oils. The best there is
Reviewed by Svt2038:
Let's be honest it's hard to rate in oil...My wife's vehicle calls for this weight. I do use Amsoil in all of my other vehicles so it just made sense. Interestingly when bought the vehicle I changed it over from conventionals oil it came with. Engine, Trans and PS changed. I saw a consistant 1.5 MPG gallon increase(70% highway/25% city).
Reviewed by LBS27:
I run Amsoil in everything I own, from motorcycles to cars to antique tractors. Why not spend less time under your vehicle a year changing oil? Great oil!
Reviewed by Zen:
Best synthetic motor oil that I've used on my car.
Reviewed by BK:
I have driven my Acura TL for over 100k miles using the Signature 5w-20 synthetic. I will use no other!
Reviewed by Orest:
I currently use the 5W20 oil in my 2014 Dodge Caravan, (also previously in my 2006 Dodge Van), and in my 2008 Dodge Dakota truck and very satisfied with this product.
I also use 10W30 in my motorhome and have done so for the past 20 years, again with complete satisfaction.
As I live on an acreage, I also use 10W30 in my garden/lawn tractor, and have done so for the past 20 years.
In my opinion, this is the only oil I would use.
Reviewed by Mike:
Use Amsoil in all 4 family vehicles, never let me down and is cheaper than conventional oil changes. Switched a 2005 F150 leased truck that I bought to Amsoil, now has 233K on it & still going strong.
Mike
Reviewed by TreeTopKiller1:
Have a new Jeep Wrangler and figured I should change out the factory oil a bit early after break-in of the engine. Used the Signature fill as I keep my vehicles for a long time. May have seen a small increase in mpg.
Reviewed by 74packman:
I switched to amsoil at 100k and original engine went 445K. Changed oil and filter every year at Christmas. No way that would have happened with conventional oil. For years now have run amsoil in everything I have. Good stuff.
Reviewed by Beef:
Signature Series 5w-20 goes in my two Honda Accords. Great oil that keeps those Honda engines going and going. each Honda has over 170,000 miles each and run great. Won't use anything else.
Reviewed by Big Jerm:
I drive a 05 ram with the Hemi. It holds 7 qts and oil changes were getting expensive. I noticed no matter the brand i would use at least 1-2 qts between oil changes which was around 3000 to 4500 miles. Since swapping to the signature series i went for an initial interval of 15000 miles. I noticed i would only use 1 qt every 5000 miles. I also noticed the truck doesn't tick and i haven't noticed a significant change in fuel economy. But i will be buying again this time attempting 25000 miles.
Reviewed by Ff:
Best oil around
Reviewed by Navy Cobra 02:
I have been using AMSOIL products for about 8 years now at the insistence of the guy I bought my roadster from - had never considered synthetics before. Thought they were too expensive, didn't take the time to dig into it. Now I am using them in my roadster, van, pickup, push mower, string trimmer. It was even recommended to keep my garage door hinges from squeaking by the guy who installed the door (and yes it makes them as silent as the tomb)! I took a look at AMSOIL performance on a variety of ASTM lubricant tests; you should do the same. There are other good synthetic products on the market, but I think these are the BEST: I ran 8qts in my roadster for 5 years, admittedly not a lot of mileage on that car, maybe 500- miles/year but when I finally got around to having it changed I asked my shop to send a sample out for testing: 40% life remaining (in general terms). Folks, it's a no brainer in my opinion...why not buy the best to keep your engines running smoothly, cleaner, and cooler?
Reviewed by Ed:
Use it in all 3 of my Dodge vehicles. Outstanding value.
Reviewed by Big Dave:
Best protection money can buy. I know this oil is protecting my truck even through high demands of Phoenix summers.
Reviewed by Road Glider:
How can we spend so much for our vehicles and not want to take the best care of them we can? I've used AMSOIL's lubricants in every vehicle I've owned for many years, and have always felt I was taking the best care of them I could. The 5w20 Signature Series I use in my 2013 Dodge Durango has given me so much peace of mind. Why would I want to use anything else?
Reviewed by Mongo72:
Have 303,327 miles on the 03 honda civic,and still get 38 MPG.No smoke out the tailpipe,and still change the oil at 25,000 miles.Signature Series oil works for me ,the proof is the civic,not snake oil.
Reviewed by Squire:
One vehicle I have is a 1988 Bronco II 2.9 engine 5speed. I have all Amsoil lubricants installed in it. THE ENGINE REALLY LOVES THE 5W30 Signature series oil.The Amsoil fluids really make a difference.Thanks Paul
Reviewed by sly:
This oil, for what I do is excellent. I get between 15000 km to 20000 km before the next oil change and my gas mileage is a little better and the oil filter you only change every second oil change. I would recommend this oil for anyone.
Reviewed by Grosspolluter:
Are used to use Pennzoil 1030 all the time aside to switch synthetic when I bought a new her car with low mileage and I use synthetic and all mine your engines and I like the amzoil product so far no problems
Reviewed by Rene:
I love this product it make what suppose to do and long life
Reviewed by Steven:
I use amsoil because of the superior protection and longer change intervals this product has been the best oil I have ever purchased and used for my truck boat and even my lawnmower
Reviewed by JGTX:
Great product to maintain my daily driver
Reviewed by Sufiztic:
I'm a car guy. I've used all the top name brands u can think of, but no oil has ever given me 20k+ miles on a single oil change, and I drive my cars hard.
I've done and undone engines with friends and never seen cleaner internals with Amsoil in it. I'm a forever Amsoil Customer!
Reviewed by Dave507:
Great product
Reviewed by NA:
I use it in my vehicles. I like not having to change my oil every 3000 miles. I have had great luck with this oil. I will continue to use this oil.
Reviewed by Berniemac:
Use this oil in a Ford Raptor that travels cross country. I trust this lub for high mileage protection.
Reviewed by Allen:
great product
Reviewed by Old Man Engine:
Fast service, knowledgeable about product, fast shipping.
Reviewed by Eazy E:
Saves me money in the long run. Less oil changes. Great performance!
Reviewed by Mikado:
I use it in my car,change my oile 1 time and forget it
Reviewed by PolarBear00777:
I have been a long time user of AMSOIL products in everything I own and I have found that the 5W20 is the absolute best engine oil. It has almost the same low temperature benefits as the 0W20 but less burn off than either the 0W20, 0W30 or 5W30 engine oils. It is the only oil I use for my customers now.
Reviewed by Paul:
Great product. Been using Amsoil for about ten years. My only complaint was the shipping charge. Amsoil has been running specials for preferred customers were they've been offering free shipping on orders over over a certain amount. When they offer this deal that's when I place my order.
Reviewed by flexsilver:
my '05 Mustang GT is a daily driver ( winters too ) with 165,000 kilometres ( about 100,000miles ). I only use Amsoil products and whenever I do oil changes at the dealership/shops, they always comment on how clean the oil still is - although you can go 1 year before changing, I change my oil sooner as it is a daily driver in a busy,dusty environment. I use the EA011 oil filter plus steering/transmission fluids and Severe Gear rear differential fluid and Slip Lock additive. I used to use Amsoil brake fluid but it can no longer be sold in Canada. Thanks Amsoil for the great products and service. Kevin Miller
Reviewed by ENORMOUS:
I have been an Amsoil customer/member for over a decade. This is probably one of my favorite companies around. Thank you for an excellent product and customer service. Oil & full-flow EaO filters keep my vehicles in tip-top shape year in and year out. I even go as far as testing the motor oil through an independent lab, the results are top-notch wear and tear. Without reservation, Amsoil is hands-down second to NONE!
Reviewed by MR.G:
I have been using AMSOIL products since 2002,I have never had a problem with ordering,shipping,billing,or product quality.I am very happy with all aspects of AMSOIL.
Reviewed by diamonbird:
Been using Amsoil since 2001 nothing else can compare.
Reviewed by Moe:
I 've used this oil for a long time never wanted to try anything else like oil with color in it I just wanted a truly good product thats why I stayed with Amsoil hasn't let me down and I recommend it to everyone
Reviewed by runner:
Used amsoil for 20+ years. SS series is great for long drain intervals. All of my engines have many miles on them thanks to protection this oil gives.
Reviewed by Luis:
I use it on my ford vehicles. The product and lab reports on it speak for themselves. This is a must product if your vehicle requires it.
Reviewed by Daniel:
Always I put in my Linconln, Navegator and MKT 100/ recommend. Real synthetic
Reviewed by William:
Phenomenal
Reviewed by Jeff:
Great oil, 13k between changes with their filter. 225,600 on the ticker.
This oil has been in this October 1995 F150, 351w all of its life!
Reviewed by Randolph:
Changed the oil on our 2014 Lincoln MKX.
Reviewed by
Kenny:
Love it really works for me
Reviewed by Brian:
Amsoil 5-20 oil is great. I normally run it a little over 5k miles in my truck, no more then 7k miles, and don't notice a large drop in performance from then and after the oil change.
Reviewed by Viacheslav:
Great stuff
Reviewed by Frank:
Have been using amsoil since its start before being called amsoil. Had a ford explorer for 13yrs 278,000 miles. Still had factory compression specs when I sold her.
Reviewed by Brian:
I've been using this oil in my 2010 Taurus SHO since I purchased it in 2012. I've been on an annual oil change for most of that time, but recently changed to twice a year after I had the oil analyzed to see the impact the turbos had. While the oil was holding up, it was clear that a more frequent oil change was warranted. I've used this oil in my wife's car and the predecessor of the SHO. I also use this in my 1977 Corvette (albeit a different grade) -- so all my vehicles are protected.
Reviewed by Brian:
Shortly after purchasing a 2013 Ford Edge with a V6, I switched from the oil installed by the oil change place to the Signature Series, which is what I run in all my vehicles. Annual oil change is my routine and it's clearly doing its job. I had another vehicle opened after running signature series in it for years and there was zero deposits (sludge) in any visible area (including on top of the heads where it is common). I've been using Amsoil for about 10 years and trust them to keep my cars in good running order.
Reviewed by Robert:
I have been using Amsoil products since April 1991 and trust them completely to provide the best available protection for my motor vehicles. In my opinion, there is no substitute or equal to Amsoil's many years of R&D in synthetic lubricants and their resultant superior products.
Reviewed by Mike:
I use it in 2008 Taurus and a 2015 Ford Explorer. I've used it in the Taurus since 3000 miles and it now has 115,000 miles on it and have had no engine issues and still get 22 - 25 mpg. I bought the Explorer new and have used it since the first oil change and it now has 41000 miles on it. Love the oil ! I would recommend it to anyone looking for a high quality Synthetic motor oil.
Reviewed by ANTHONY:
I have been an AMSOIL fan for two decades and continue to be super impressed.
Reviewed by Ken:
Car seems to run smother with this oil
Reviewed by Scot:
I use Amsoil Signature Series 5W-20 Oil in my 2014 Ford
F-150 for maximum protection.
The engine is the 5.0L, and it runs very well with this oil.
Reviewed by Willie:
Hands down best oil around.
Reviewed by Charles:
Put this in two cars with over 150000 miles improved gas mileage by 10%
Reviewed by Doug:
Could tell the difference the first time I changed to this oil. The van runs smoother and uses very little between changes.
Reviewed by Gordon:
I have used this in my 2008 Honda since new and runs like a top.
Reviewed by Bruce:
Not much to say. I have relied on Amsoil synthetic motor oil for 15 years now and have not had a single oil related failure in either of my vehicles, including one having a catastrophic oil leak (more like a hemorrhage) after which I drove 10 miles to a repair shop without damage to the engine.
Reviewed by Bruce:
Not much to say. I have relied on Amsoil synthetic motor oil for 15 years now and have not had a single oil related failure in either of my vehicles, including one having a catastrophic oil leak (more like a hemorrhage) that emptied the oil pan, after which I drove 10 miles to a repair shop without damage to the engine.
Reviewed by Karvoris:
I've been using Amsoil for my 2012 RAM 1500 since day one. This oil is great no issues and as of now I'm
70,000 miles in. Oil is changed annually which is approximately 14,000 per change haven't had any issues. Motor still runs strong and solid.
I look at it like this if I can invest over $30,000 into a vehicle I can invest $100 in an oil change yearly which is still cheaper than the every 3,000 miles conventional oil changes that our so common. I stand by this brand and their products.
Reviewed by Royce:
Excellent product, improves gas mileage and reduces engine wear.
Reviewed by Curtis:
Amsoil is the only oil that I purchase, I said purchase be cause I don't use oil (or burn oil) in1994 a friend had a cat engine in his over the road tractor trailer rig, He had 1.2 Million miles on it and a cam follower broke on the valves so he had to pull the hole front end down to
replace the cam. He told the shop to go ahead and do a in frame overhaul so they mike all the parts, and they were all at Factory specs. that's when I be came a Amsoil customer. I Have It in my Truck, Car, Harley, Quads, lawnmower, power washer. Boat, and Chain saw. I wont use any thing else. It wont break down with Heat.
Curtis T. Sherwood
Reviewed by Leonard:
year round for Ford Focus
Reviewed by Richard:
This oil and filter made my 5.7L V8 Toyota Tundra a whole other animal! Engine definitely runs smoother than the last 240k miles I did on it and I have noticed about a 1mpg gain. I also noticed a smoother acceleration and a bit faster too! If u want a long lasting a smooth running engine then this is definitely the oil for you.
Reviewed by Mad Max:
I've been using Amsoil since 1989 when I use to race snowmobiles in the north east the product never let me down. I used Amsoil in motorcycles, 4 wheeler and side by side again this product came through no matter what abuse I put my toys through. I've recently got into cars since my move to NC I have 2015 Mustang GT that's pushing 703 RWHP AND 600 FPTQ to the wheels from past experience with Amsoil the only oil for my ride would have to be Amsoil. I ran a (153) 1/2 mile in Clayton GA at Heavens Landing this year and plan on taking the car in March to the Texas mile. Amsoil is so much more than oil I use there anti freeze, gear oil, octane boost and much more. The Staff is outstanding, the shipping to your front door is insanely fast and well packaged. Thanks Team Amsoil for a great 27 years and hope to have many more ahead of me.
Reviewed by Lenden:
I use Amsoil in all my motors. Gas and Diesel. Cars , Pickup Diesel , Tractor Diesel, Stays cleaner and last longer. Has reduced oil consumption on high mileage motors.
Reviewed by Leon:
Bought a new Tundra for the wife. When due for the first change I went wild and changed it all to amsoil. I believe this coupled with CAI is what gave us the 1.5mi gas increase!! Plus always better with the piece of mind I get with my amsoil products.
Reviewed by Thomas:
Love the oil and extended service intervals. Gas mileage went up as well.
Reviewed by Mad Max:
I first discovered Amsoil when I started racing snowmobiles in 1988, I've always found that amasoil always came through and could handle extremely cold temperatures. When I was into motorcycles once again Amsoil was my first choice if it was my 2003 V-max with 162 RWHP or my Vrod again Amsoil product are second to none. I'm starting to play in the car seen and have a 2015 mustang GT pushing 650 RWHP & 562 RWTQ I wouldn't trust any other oil in my insanely fun weekend car. Amsoil thanks for a fantastic 28 years and hopefully 28 more..
Reviewed by Southern Wolf:
I have been using Amsoil in three of my vehicles now. One I sold with about 280k miles and it did not use any oil. As soon as I got my new car home I change out the factory oil to Amsoil. I have a Jeep Wangler that I put a performance Chevy 350 in., 340 hp 390 ft lb torque. I have had over heating problems with it and have driven it all day with temps over 230. The oil did not cook and I still don't use oil, I've put over 60k on this engine using the Z Rod oil.
Reviewed by Andy:
Have used AMSOIL oils and filters for several years now. Can tell a difference just by loooking at the oile when changing. Other oils when drained show wear by the dark color. With AMSOIL it looks like it could go a few more thousand miles.
Reviewed by BC:
Tried Amsoil products at the advice of a good friend, very satisfied with the results! I have a rotary motor and as you know they are very tough on engine oil, after 2000+ miles the oil looks almost new, great stuff!
Reviewed by Bullseye Tom:
I use 5W-30 signature series in my 2005 Mercury Sable 3.5 liter V-6. I get quick starts in the depth of winter (-10 - 15F) and smooth running in mid summer on the interstates. I would never by choice subject my vehicles to a lesser lubricant series that Amsoil fully synthetic motor oil and transmission fluids.
Reviewed by War Path:
One of the best Oils on the Market, I have use this product and several others from Amsoil in every motor
I own and have never had a failure. From 2 cycle lawn equipment, all my cars, both diesel and gas boat motors everything has been run on Amsoil. Started back when I raced Snowmobiles, and beat all the factory teams.
Reviewed by Mitchell:
The only oil that I use. Have been using it for 20 years. Best on the market.
🙌
Reviewed by Jamie:
I drive a lifted 2005 Ram mainly used for towing an enclosed race car trailer and noticed an increase in engine performance, and a MPG increase.
Reviewed by Rod:
It is expensive, but to only worry about changing oil and filter every 25k miles is worth it in convenience. We have a Mustang with 170k miles, a Ford 500 with 130K miles, and an F-250 with 98k miles. The only problem with the pickup is that it uses a quart and a half between oil changes, so that increases the cost.
Reviewed by olestick:
Great, great oil all I will use in both of my vehicles
Reviewed by Just a guy:
When my service shop mistakenly changed my oil to regular oil I noticed a dip in my mpg by a little more than 1 mile per gallon. I suspect that it would be more than that in the winter months plus easier to start and less wear on my battery and starter.
Reviewed by TigerRoush:
After reviewing oils including Royal Purple, Mobile 1 etc I found Amsoil to be top notch.
I would not use anything else in my vehicles. I also use the Amsoil oil filters which are the best.
Amsoil is higher in price but quality of product and piece of mind that my engine is protected is priceless.
Reviewed by Joey:
I purchased a Chevy truck with a Duramax engine and got information that Amsoil was the oil Duramax owners used so I started using Amsoil, I purchased a 2004 Honda Accord with 202,000 miles on it for a vehicle to drive to work, the former owner said that the oil was always changed on time with Honda brand oil, he said that it would use about a quart between changes, first thing I done was change the oil, put this signature series 5W-20 synthetic in it also used the amsoil filter, 3000 miles it used about a quart, changed the oil at 3000 miles, went 5000 miles on the second change didn't have to add any oil to it, may have used a half a quart, changed it at 5000 miles, hoping it won't use any after this next 5000 miles, to me this signature series has to be doing a good job to make a 210,000 mile car go 5000 miles between oil changes with no oil consumption.
Reviewed by Jeff:
I use Amsoil signature series engine oil in my Ford Expedition. I have had an independent oil test done after 25,000 miles and it showed the oil to still be ok. It may be one expensive oil change but considering how much longer you can run the oil vs. changing it every 3000 miles this is a lot cheaper and a lot less Saturday afternoons wasted changing oil. Thanks Amsoil for a great product.
Reviewed by '10 Charger RT NC:
What is there to say other than it is simply the best product available. If you use synthetic, there is no reason not to use the best and Amsoil is simply the best that a non chemist like myself can find. Do not buy the Mobile 1 or other products because they might be cheaper and then depend on them like you would Amsoil. Buy Amsoil, spend the little extra and then have fun without the worry. 2010 Dodge Charger RT, Super R&T, CAI, oil catch can, Flowmaster 50's. Fun, fast, worry free. Use the full syn, 25K mile filters and change at about 10-12K miles religiously. She runs great, 102K mile thus far. Sounds great. Like the ad says, "Just Do It"! Amsoil.
Reviewed by dutch:
i have use amsoil for the last 20 years had a 7.3 d for 15yrs. had 360.000 miles on it when i sold it and not
one oil problem with it . your oils gave me better all around performance and i still use it in all my vehicles
to this day.
Reviewed by Jve1966:
In my honest opinion, I love this oil. My honda 2008 civic is at 277000 miles and i owe alot to the fact that amsoil has thw best product in the market. I usually change my oil around 25k miles. One time, I was 35000 miles on an oil change! My car still has the pep it did when I bought the car. I switched from a competition product to amsoil about 10000 miles from being new. I highly recommend this oil.
Reviewed by Manny:
I been using 5W-20 AMSOIL in my supercharged 06 Mustang for years. Runs like a champ. Also use it in my 10 F150 KR as well which I use for hauling and road trips. Wouldn't recommend any others. Great oil, provides solid protection. I use their other fluids in my vehicles as well to include my 14 VROD Muscle and 09 Nightster.
Reviewed by Ranger Pat:
I have been using Amsoil in my vehicles since 2005. The money and time I save using the extended life filters and the quality of the oil is unsurpassed. I am glad Amsoil now has oil for my Dodge Ram 1500 Eco Diesel.
Reviewed by Pops:
I did not really believe all the claims about AMSOIL until I checked for myself. I used it, had oil analysis done and was amazed at the results. I have been a user for 12 years in 4 vehicles and have no worries when it comes to lubrication of the engines internal parts.
Reviewed by WoodyJer:
I am a 15yr customer. I have been running AMSOIL in all my vehicles. One of my cars is a 97 Geo Metro with a 5 speed trans. The car has 320,000 miles on it. I use it daily to run errands. I didn't want to part with the 52 mpg so I rebuilt the engine. The transmission was hard to shift. After running amsoil 80-90w trans- oil for about a month it now shifts smooth. I have been driving both of my cars with confidence. I run amsoil 5w-20 signature series motor oil in both of my cars. The only negative I have is that I wish shipping was free. Jerry
Reviewed by DRACO:
I have been running Amsoil in my vechicles for over 10 years, now I am using 5 W 20 motor oil in my jk which I wheel often as well as daily drive, the oil is great and my vechicle appreciates it.
Reviewed by Meanmike:
I started using Amsoil Signature Series 0W-20 in March 2008. I was skeptical that oil could last a year so I tested it out on my Mercury Sable before putting it in my F150. I always used Mobile1. After one year and about 14,000 miles I sent out an oil sample to be tested. It came back no damage to the engine and that I could kept running the oil. So I ordered enough oil for the Sable and the F150 and have been running it ever since in every vehicle I own. I started using the 5W-20 when it became available. And I always use Amsoil oil filters.
Reviewed by ron:
I have used most of the major brands of synthetic oils out there in my pickups, cars and motorcycle, both gas and diesels . The increased oil change intervals alone make Amzoil signature series oils worth it. Just gage the oil changes using the on board computers and you will see the difference . Every other premium synthetic lasted approximately 6,000 to 7,000 miles going down to 5% life left. Amsoil goes over 10,000 miles on every oil change at 10% life left. defiantly a superior oil.
Reviewed by Rich:
I have been using the signature series 5w-20 synthetic motor oil in my 2005 Dodge Ram 1500 (Hemi) since it was new and after 11 years it's still running strong.
Reviewed by Nick:
I got my new Mustang up to 10000 miles which is the oil change interval and have used Amsoil for the past 5 years. I like that I can change AMSOIL once a year as it saves money in the long run plus their oils are the best. I only use AMSOIL in my cars since about 2010 and have had no issues.
Reviewed by None:
I have been using Amsoil since 1975 and love it. I have never had an oil related problem and have had mechanics comment - your engine is so clean, how did you do it. I do not exceed 12 to 15,000 miles a year on my vehicles so I change oil once a year, use Amsoil filters, change filters at 6 months - just me. I am a preferred customer and plan on using Amsoil forever.
Canada
United States
I will always Buy Amsoil Products as they are top Quality.
Has keep our Vehicles Running smoothly and efficiently.