5W-20 vs 5W-30 Oil: Which One Should You Buy?

An oil change starts with a drain pan under the car and a manual open on the workbench, and the grade on the cap does not match the jug on the shelf. For 5w-20 vs 5w-30 oil, the answer is direct: use a grade listed in the manual, and choose among the oils that match that grade by size, formula, and stated protection. The listings in this guide are all 5W-20 oils, so the gear section below covers 5W-20 choices in detail, while the grade choice itself stays with the manual.

Other tools worth a look

• Valvoline Advanced Full Synthetic SAE 5W-20 Motor Oil 5 QTCheck price on Amazon
• Pennzoil Ultra Platinum Full Synthetic 5W-20 Motor OilCheck price on Amazon
• Castrol GTX Full Synthetic 5W-20 Motor OilCheck price on Amazon
• Castrol EDGE 5W-20 Advanced Full Synthetic Motor OilCheck price on Amazon
• Castrol GTX 5W-20 Synthetic Blend Motor OilCheck price on Amazon
• Pennzoil High Mileage 5W-20 Motor OilCheck price on Amazon

GarageToolHQ earns a commission when you buy through links on this page, at no extra cost to you. Read the affiliate disclosure.

Below: what the listings actually state about these grades and oils, a table of the gear oils, the gear oils in ranked order, and a checklist for choosing between the grades.

5w-20 vs 5w-30 oil: what the listings actually state

The grade label is the starting point, not the whole choice. A listing states a grade, a size, a formula, and a set of protection claims, and those stated facts differ even among oils that share the same grade. In this guide, every gear listing states 5W-20, with sizes of 5 Quart or 5 QT for most oils and 1 Quart for the Pennzoil listing, and formulas of full synthetic for most oils and synthetic blend for the Valvoline MaxLife listing. No gear listing here states 5W-30, so this guide does not compare a 5W-30 oil by size or formula, and it does not state a performance figure for 5W-30 that no listing gives.

That gap is why the manual matters more than a general rule. A manual that lists 5W-20 points to the oils below, while a manual that lists only 5W-30 points elsewhere, and a listing that states a grade, a size, and a certification should be checked against the grades and codes the manual lists before any other feature is weighed. Certifications stated here include ILSAC GF-6A and ILSAC GF-7A, plus API SP, API SN, and API SQ on various listings, and those codes should be checked against the manual as well.

The gear: 5W-20 oils, ranked

Pennzoil Ultra Platinum 5W-20. The listing states a full synthetic 5W-20 engine oil, made with natural gas, designed for high-performance engines, with outstanding performance in extreme temperatures as stated by the maker. Its standout stated fact is a 20-year, 750,000 mile warranty, which no other listing here states in a concrete term. The trade-off is size: at 1 Quart, it is the smallest jug here, so the amount needed for a full oil change should be checked against the manual before counting on a single jug.

Mobil 1 High Mileage 5W-20. The listing states a full synthetic 5W-20 oil in a 5 Quart size, for engines at 75,000+ miles, with a seal conditioner and additives to help fight sludge. It states protection for 15,000 miles, which is a clear, stated protection figure for a high-mileage engine. It suits a garage where a high-mileage engine needs a seal conditioner, and where the manual lists 5W-20.

Valvoline Advanced 5W-20. The listing states a full synthetic SAE 5W-20 motor oil in a 5 QT size, with advanced protection against wear, friction, heat, and deposits as stated by the maker. It states 40% better wear protection and 25% better deposit protection, plus 24X stronger protection against engine-killing contaminants than the leading full synthetic motor oil, as stated in the listing. It also states ILSAC GF-6A, API SP, and API SN with SN Plus, which should be checked against the manual.

Valvoline MaxLife 5W-20. The listing states a synthetic blend 5W-20 oil in a 5 Quart size, formulated for engines with 75,000 miles or more, with seal conditioners to help prevent oil leaks and reduce oil consumption. It states 20% better wear protection and 15% better sludge defense than industry standards, plus extra detergents against friction, corrosion, and deposits, and it states ILSAC GF-7A, API SQ, API SP, and API SN with SN PLUS. It is the synthetic blend in this set, while the other gear oils here state full synthetic formulas, and it still offers a high-mileage formula in a large jug.

How to choose between 5w-20 and 5w-30 oil

1. Confirm the grade in the manual. Check the grades listed in the manual, and the gear oils here are all 5W-20, so a manual that lists only 5W-30 points to a different listing.
2. Check the size. Most gear oils here state 5 Quart or 5 QT, while the Pennzoil listing states 1 Quart, so check the amount the manual calls for before choosing a jug size.
3. Check the high-mileage need. The Mobil 1 and Valvoline MaxLife listings state high-mileage formulas for engines at 75,000 miles or more, with seal conditioners stated, while the other listings do not state a high-mileage focus.
4. Check the certifications. Compare the ILSAC and API codes stated on a listing, such as ILSAC GF-6A, ILSAC GF-7A, API SP, API SN, and API SQ, against the codes the manual lists.
5. Check the warranty term. The Pennzoil listing states a 20-year, 750,000 mile warranty, while other listings here state no concrete warranty term, so warranty should not be assumed where it is not stated.

FAQ: garage tools

Can I use 5W-30 if the manual calls for 5W-20?

Check the grades the manual lists. If the manual lists only 5W-20, the gear listings here fit that listing, while a manual that lists only 5W-30 points to a different listing. Do not swap grades on the basis of a protection figure alone.

Which size should I buy?

Check the amount the manual calls for, then compare it with the jug size stated on the listing. Most gear oils here state 5 Quart or 5 QT, while the Pennzoil listing states 1 Quart, so check the total amount needed and buy enough oil in those jug sizes.

What is a high-mileage oil for?

According to the listings here, high-mileage oils are formulated for engines at 75,000 miles or more, with seal conditioners to help prevent oil leaks and reduce oil consumption. The Mobil 1 and Valvoline MaxLife listings both state that high-mileage focus.

Do these oils meet stated industry standards?

The listings state various codes that should be checked against the manual, including ILSAC GF-6A on the Valvoline Advanced listing, ILSAC GF-7A on the Valvoline MaxLife listing, and API SP, API SN, and API SQ across the listings. A code on a listing should meet or exceed the code the manual lists.

How long does protection last?

Protection figures differ by listing and should not be mixed with warranty terms. The Mobil 1 listing states protection for 15,000 miles, while the Pennzoil listing states a 20-year, 750,000 mile warranty, and other listings here state protection figures in percentages rather than miles.

Related: the synthetic vs conventional motor oil guide, the best motor oil 5w-30 full synthetic picks, the best motor oil additive picks and the engine and shop equipment category.