Rick's Free Auto Repair Advice

What is the right oil for your car?

What is the right oil for your car?

Do you know for sure what is the right oil for your car?

Everyone has an opinion about which oil viscosity they should and how long they can go between oil changes. But opinions don’t count. All the information you’ve ever known about motor oil is obsolete. Newer oil and newer engines are completely different than the motor oil you grew up with.

Engines now have variable valve timing (VVT), gasoline direct injection (DI), and turbos that place different demands on oil. For example, DI requires fuel pressure of up to 2,000-psi. So your car has two fuel pumps—one in the tank to deliver fuel to the engine pump and a second high pressure pump. The high pressure pump runs off the triangular lobe on the camshaft. If you use the wrong oil-either the wrong viscosity or the wrong service rating- you can damage the camshaft. And when it comes to turbos, you need an oil that won’t break down under high heat conditions. Plus VVT has it’s own unique operating conditions. The engine computer changes valve timing with a hydraulic actuator. The actuator moves based on pulsed oil pressure from a pulsing solenoid. The computer commands valve timing changes based on factory recommended oil viscosity. Change to a different viscosity or a different service rating and the actuator won’t respond properly. That’ll set a check engine light and affect engine performance and emissions. AND, because it’s pulsed, the oil can develop air pocket and foam. Foam doesn’t cool metal – it actually insulates, so the oil runs hotter and degrades faster.

Let’s start with factory recommended viscosity, service classifications, and the certification organizations

Your owner’s manual lists the recommended an oil viscosity for your engine. But viscosity is just the starting point. Next you have to know the minimum service rating for your motor oil. That can be listed as an American Petroleum Institute (API) service classification, International Lubricants Standardization and Approval Committee (ILSAC), and ACEA.

API

The API program certifies that an oil meets certain Original Equipment

Manufacturer (OEM) quality and performance standards. The service rating is shown in the API “Service Symbol Donut” on the product label. The label shows the motor oil’s viscosity and service classification. The current API classification is “SN.” “S” stands for gasoline engines and “C” stands for diesel engines. The second letter in the most important. The first API service classification was “SA.” That motor oil was designed to work in cars built before 1930. As oil requirements changed, so did the API service classifications, from SB, SC, SD, SE, SF, SG, SH, SJ, SL, and SM to its current level of API SN.

 

oil viscosity, oil rating, SN

API Starburst Symbol

 

ILSAC

 

ILSAC was formed in 1992 by the American Automobile Manufacturers Association and the Japan Automobile Manufacturers Association to develop an international service classification for oil.

For example, ILSAC GF-1 was created in 1990 and upgraded in 1992. It was the minimum requirement for motor oil used in American and Japanese automobiles.

 

GF-2 replaced GF-1 in 1996. GF-2 must meet the API SJ service classification and requires 0W-30, 0W-40, 5W-20, 5W-30, 5W-40, 5W-50, 10W-30, 10W-40 and 10W-50 motor oils to meet tougher requirements for phosphorus content, low temperature operation, high temperature deposits and foam control.

GF-3 oil must meet the API SL service classification and tougher standards for long-term effects of the oil on the vehicle emission system, improved fuel economy and improved volatility, deposit control and viscosity performance. The standard also requires less additive degradation and reduced oil consumption rates over the service life of the oil.

GF-4 oil is similar to the API SM service category, but must also meet a tough fuel economy requirement. It provides improved high temperature deposit protection for pistons and turbochargers, better stringent sludge control, improved fuel economy, enhanced emission control system compatibility, seal compatibility, and protection of engines operating on ethanol-containing fuels up to E85.

GF-5 is the most current rating.

API and ILSAC ratings are backwards compatible, so you can use the most up to date oil in your older vehicle (pre-80’s vehicles without catalytic converters may need an extra ZDDP anti-wear additive). But you can’t use an older rating, like SJ or GF-4 in an engine that requires SN or GF-5. Stores still sell that older oil, so read the label before you buy.

ACEA and European Vehicles.

Many European vehicles require oil that meets ACEA specifications or the car maker writes their own specifications based on the exact requirements of a particular engine setup. In other words, application-specific oil. Let’s start with the ACEA system.

First, ACEA rated oil is NOT backwards compatible. If your car maker specifies a certain ACEA rated oil and there are newer oil available, you CANNOT substitute those motor oils for use in your engine without causing substantial damage. Secondly, ACEA oils are designed generally for extended drain intervals, as opposed to the fuel economy issues that drive many API and ILSAC rated oils.

The following information is quoted directly from the ACEA 2012 EUROPEAN OIL SEQUENCES FOR SERVICE-FILL OILS literature dated Dec. 2012

Each set of sequences is designated for consumer use by a 2 part code comprising a letter to define the CLASS (e.g. C), and a number to define the CATEGORY (e.g. C1).

In addition, for industry use, each sequence has a two-digit number to identify the YEAR of implementation of that severity level (e.g. A1 / B1-04).

The CLASS indicates oil intended for a general type of engine – currently A / B = gasoline and light duty diesel engines; C = catalyst compatible oils for gasoline and diesel engines with after treatment devices. Other classes may be added in future if, for example, Natural Gas engines prove to require oil characteristics which cannot readily be incorporated into existing classes.

The CATEGORY indicates oils for different purposes or applications within that general class, related to some aspect or aspects of the performance level of the oil. Typical applications for each sequence are described below for guidance only. Specific applications of each sequence are the responsibility of the individual motor manufacturer for their own vehicles and engines. Oils within a category may also meet the requirements of another category, but some engines may only be satisfied by oils of one category within a class.

The YEAR numbers for ACEA Sequence is intended only for industry use and indicates the year of implementation of that severity level for the particular category. A new year number will indicate, for example, that a new test, parameter or limit has been incorporated in the category to meet new / upgraded performance requirements whilst remaining compatible with existing applications. An update must always satisfy the applications of the previous issue. If this is not the case, then a new category is required.

An administrative ISSUE Number is added for industry use where it is necessary to update the technical requirements of a sequence without the intention to increase severity (e.g. when a CEC test engine is updated to the latest version whilst maintaining equivalent severity; or where a severity shift in the test requires modification of the specified limits.).

ACEA EUROPEAN OIL SEQUENCES

 A1/B1 Stable, stay-in-grade oil intended for use at extended drain intervals in gasoline engines and car & light van diesel engines specifically designed to be capable of using low friction low viscosity oils with a high temperature / high shear rate viscosity of 2.6 mPa*s for xW/20 and 2.9 to 3.5 mPa.s for all other viscosity grades. These oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

A3/B3 Stable, stay-in-grade oil intended for use in high performance gasoline engines and car & light van diesel engines and/or for extended drain intervals where specified by the engine manufacturer, and/or for year-round use of low viscosity oils, and/or for severe operating conditions as defined by the engine manufacturer.

 A3/B4 Stable, stay-in-grade oil intended for use in high performance gasoline and direct injection diesel engines, but also suitable for applications described under A3/B3.

 A5/B5 Stable, stay-in-grade oil intended for use at extended drain intervals in high performance gasoline engines and car & light van diesel engines designed to be capable of using low friction low viscosity oils with a High temperature / High shear rate (HTHS) viscosity of 2.9 to 3.5 mPa.s. These oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

 C : Catalyst compatibility oils

C1 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines requiring low friction, low viscosity, low SAPS oils with a minimum HTHS viscosity of 2.9 mPa.s. These oils will increase the DPF and TWC life and maintain the vehicles fuel economy.

Warning: these oils have the lowest SAPS limits and are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

C2 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines designed to be capable of using low friction, low viscosity oils with a minimum HTHS viscosity of 2.9mPa.s. These oils will increase the DPF and TWC life and maintain the vehicles fuel economy.

Warning: these oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

C3 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines, with a minimum HTHS viscosity of 3.5mPa.s. These oils will increase the DPF and TWC life.

Warning: these oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

C4 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines requiring low SAPS oil with a minimum HTHS viscosity of 3.5mPa.s. These oils will increase the DPF and TWC life.

Warning: these oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

 SAPS : Sulphated Ash, Phosphorus, Sulphur

DPF : Diesel Particulate Filter

TWC : Three way catalyst

HTHS : High temperature / High shear rate viscosity

Application-specific oil

In addition to, or in place of an ACEA rating, your European car owner’s manual may list a specification for oil. Here are some examples.

Audi: 501.01, 502.00, 505.00, 505.01, 504.00 and 507.00

Mercedes Benz: MB 229.3, 229.5, 229.31, 229.51.

Volkswagon: 505.01, 502.00, & 505.00

Porsche A40

BMW Long Life 04

BMW Long Life 01

If take your car to a shop for oil changes, and your manual lists an application-specific oil, make sure the shop has that oil on-hand. The shop may charge more for the special oil, but it’ll keep your engine running longer.

SUMMARY regarding choosing the right viscosity and service classification

It boils down to this; The engine designers know more than you. You can’t second guess them unless you want to take full responsibility for damaging your engine. Use the wrong oil and you can destroy your engine. The damage won’t be covered by the factory powertrain warranty or your extended warranty.

What about oil for older cars

This is pretty simple. Your older car was designed for an older oil. Newer oil provides better protection in many cases. But your older car isn’t in the same condition as when it was new. Now it has wear on the piston rings and it’s generating more blow-by gas. Blow-by means more acid, soot, corrosion, varnish, and sludge formation in the crankcase and throughout the entire engine. That’s why switching to a synthetic oil may make more sense. It has a more robust additive package to neutralize the contaminants and keep your engine cleaner. It flows faster at startup and builds pressure more rapidly. So it reduces cold startup wear and actually prolongs the life of your engine. The extra anti-wear additives offer greater protection against further wear.

But switch to synthetic oil for the prolonged engine life benefits, not extended oil changes. Because you STILL have to change synthetic oil at the same intervals as conventional oil. You cannot override the car makers recommendations. So it’s going to cost more. But your engine will last longer. You do the math.

Higher viscosity oil in a high mileage engine.

Many wanna-be mechanics think that older engines need a higher viscosity oil to combat low oil pressure and engine wear. WRONG. Higher viscosity oil does create higher pressure because it resists flow. But there’s a cost to that. Less flow means higher oil temperatures and more rapid oil breakdown. So your engine will run hotter and get worse gas mileage. The lower flow rates will cause rapid additive breakdown, so you’ll actually get less protection against wear and deposit formation (sludge).

Instead of using a higher viscosity oil, switch to a high mileage synthetic oil. High mileage oil contains film strengthening additives to improve ring sealing and oil pressure. And some brands, like Valvoline MaxLife also include seal conditioners to soften stiff seals, as well as extra anti-oxidant, anti-corrosion, anti-wear, and detergent additives to handle the additional crud in the crankcase.

When should you change oil?

Here’s where all the wanna-be experts come out of the closet. If anybody tells you how long you can go between oil changes, but they don’t ask about your driving habits, they are full of it. It’s that simple. The way you drive your car impacts how long the oil will last. NOBODY can get you an oil change interval without knowing that information.

Frequent cold starts dump raw fuel into the crankcase, diluting the oil and causing more cold start-up wear. Unless you drive the car for long periods after a cold start-up, that excess fuel and water will form sludge. Read this quote from The Center for Auto Safety:

“The Center for Auto Safety (www.autosafety.org) has logged over a thousand complaints about oil sludging problems from motorists who thought they were following the service intervals recommended in their owners manuals but ended up with a crankcase full of sludge.

Extended oil change intervals of 7,500 or 10,000 miles or more are based on ideal operating conditions, not the type of short trip, stop and go driving that is typical for many motorists. Consequently, most drivers should follow a “severe” service maintenance schedule rather than a “normal” service schedule to protect their engines.

Severe service includes:

* Most trips are less than 4 miles.

* Most trips are less than 10 miles when outside temperatures remain below freezing.

* Prolonged high speed driving during hot weather.

* Idling for extended periods and continued low speed operation (as when driving in stop-and-go traffic).

* Towing a trailer.

* Driving in dusty or heavily polluted areas.”

Some engines, such as diesels, suffer more blow-by than others and typically require more frequent oil and filter changes. For most passenger car and light truck diesels, the oil should be changed every 3,000 miles without exception — especially in turbo diesels.

Turbocharged gasoline engines also require more frequent oil changes because of the high temperatures inside the turbo that can oxidize oil. A 3,000 mile oil change interval is also recommended for all turbocharged gasoline engines.

So what about those extended life oils?

We all know that some oil companies advertise oil that can go 15,000 or 25,000 miles between changes, or oil that comes with a 300,000 mile engine guarantee. Are they for real? Well, first read their qualifying statements. You’ll see that the 25,000 mile interval don’t apply if you do severe driving. And, some of the warranties state that you must have followed the factory oil change guidelines up to the point where you switch to their product (be prepared to prove it). Yet, even after you switch, you may still be required to follow the car maker’s oil change schedule even with their premium oil, which can be as often as every 3,0000 miles.

In addition to those caveats, the warranties also go on to require you to maintain your vehicle properly and according the car maker’s schedule. That means spark plug changes must be on-time (they don’t want their oil contaminated by misfire blow-by), and you must maintain all the factory emissions sensors and components.

Oil analysis is one way out

There’s only one safe way to extend your oil change intervals with a premium synthetic oil—perform an oil analysis. Unfortunately, most synthetic enthusiasts do it wrong. The correct way to monitor your oil is to perform at least three tests. Perform the first one at the 5,000 mile mark. Then repeat the test at 3,000 mile intervals until the oil nears its end of life. That’s the only to establish a real-world oil life timeline that’s based on your engine and your particular driving habits. Repeat the entire procedure every 50,000 to account for engine wear and adjust your oil change intervals accordingly.

Or skip the analysis

This will anger a lot of enthusiasts, but I think you’re all crazy to spend money on oil analysis. To squeeze a bit more life out of oil, you’re spending far more than the cost of an oil change. In the old days you could argue that you’re saving the environment. But these days when most oil is recycled and reused, what’s the point? Are you just trying to enrich the testing labs?

Then there’s the issue of running on low oil

Most people think the oil light will go on when they’re low on oil. WRONG. Because unless you own a luxury vehicle with an oil level sensor, your oil light is actually just an oil PRESSURE light that goes on when you drop below 7-psi. At that point you either have an oil pump problem or you’re dangerously low on oil.

All engines burn oil. And if you drive your car when it’s low on oil, you put extra stress on the remaining oil. Driving a quart low puts wears out the remaining oil 20-25% faster. So you’ve actually reduced the oil change interval by at least 1,000 miles.

So quit your lazy ways and get back in the habit of checking the dipstick. Add oil to bring the level back to the full mark, even if it’s down just a half-quart

Can you trust the factory oil change light

Some oil change reminder lights are based simply on the odometer. So they don’t take your driving habits into account. In that case, adjust your oil change intervals according to how you drive. However, oil life monitoring systems do track your driving habits. The computer records the number of cold starts, ambient temperature and engine temperatures during startup, how long you drive between starts, engine load, and whether the miles are highway or stop-and-go. It runs that data through an algorithm to estimate the remaining oil life. If you do a lot of short trip city driving, the light will come on sooner than if you take a long trip.

Unfortunately, several car makers have been too optimistic in building their algorithms. Some car makers have had to pay for major engine repairs even though the customers followed the oil change light to the letter. Car makers have been forced to reprogram the oil life monitoring systems to compensate for their overly optimistic intervals.

Given that most drivers see the light, make a mental note and then postpone the actual oil change until they’ve accumulated at least 500 more miles, you can see where you’re setting yourself up for problems. You can trust the car makers oil life monitoring systems only work if you use the recommended oil and don’t add any aftermarket additives. Pour in some miracle oil stabilizer and all bets are off.

 How to protect your warranty

If you do your own oil changes and want to maintain your factory or aftermarket warranty coverage, you’re going to have to prove you changed your oil on time. I do it by tearing off the box top from the filter and cutting out the UPC symbol from the oil bottle. Then I put them in an envelope with the date, mileage and type of oil used. Seal it and you’ve got some proof.

If you take your car in for oil changes, have the shop include the oil viscosity and service rating on the receipt.

 

National Conference on Weights and Measures (NCWM) adopted standards that require shops to list the brand, viscosity and API service category of the oil they sell on their customer invoices.

Starting Jan. 1, 2014, many states are implementing the new NCWM rules and will require service facilities to label bulk containers, print the oil information on all job tickets and retain the paperwork for at least one year. Check with the appropriate government agency to find out if these new rules apply in your state.

 

 

 

 

 

 

 

 

Posted on by Rick Muscoplat


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