The last word on oil change intervals?

[JimBee]

I came across this article. Seems well researched. Indicts quick oil change joints. Argues for 6k to much higher intervals. Would it apply to older engines? 850s? What do you think?
http://www.edmunds.com/car-care/stop-ch ... 58&msite=w

[FlyingVolvo]

It's true. Most quick-lube places or auto stores will still try and sell you the 3,000 mile myth. Why? It's good for business. Many people have been doing 10,000+ mile changes since the 80s. A couple of my friends in Germany laugh even at my normal 7500 changes. The US is far behind the times when it comes to oil change interval mentality. As the article states, most manufacturers are beginning to see the light. Personally, I've done a couple 10,000 mile changes on my engine, nothing's blown up yet. Almost at 200K now. Oil analysis showed everything was good. The oils that are available now are far more technologically advanced than any of the oils available even when our cars were built (pre-2000).

[cn90]

Whether the engine is from a 1980 Honda Civic or the Volvo 850 or the 2011 Volvo, engine lubrication principles are the same. The crankshaft bearing, camshafts etc. need oil.

If one gets in the car and drive 100-200 miles/day non-stop, a 15K interval is prob. OK. The problem is: most motorists do not know what they do everyday (going to work, shopping etc.) belongs to the "severe service history" category.

The problem is blow-by combustion products.

Just google "BMW sludge", those people follow the 15K O.C.I. as prescribed by BMW, guess what? They get engine sludge.

PS: I use synthetic and change it out every 5K-6K because I believe in Larry Carley, the guru!


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This is an excellent article by the car guru Larry Carley: How Often Should You Change Oil?

http://www.aa1car.com/library/how_often_change_oil.htm

How often should you change your motor oil? On most late model vehicles, the factory recommended service interval for changing your oil and oil filter is typically once a year or every 5,000 to 7,500 miles (which ever comes first). Some vehicle manufacturers even recommend 10,000 mile oil change intervals. Others have no recommended service interval but instead rely on an oil service reminder light to let you know when an oil change is due. Some oil reminder lights may not come on for as many as 10,000 to 12,000 miles or more under ideal driving conditions (Note: such extended oil intervals are usually based on using a synthetic motor oil, not conventional motor oil).

For passenger car and light truck diesel engines and turbocharged gasoline engines, the traditional recommended service interval is typically every 3,000 miles or six months (which ever comes first). But this recommendation has changed on most late model cars and trucks.

How Long Should You Wait To Change Oil?

If you read the fine print in your owners manual scheduled maintenance section, you will often discover that many extended oil change intervals (those beyond 5,000 miles) are for vehicles that are driven under "ideal" operating conditions. What most of us think of as "normal" driving is actually "severe service" driving as far as the oil is concerned.

Severe service driving includes:

Frequent short trips (less than 10 miles, especially during cold weather)

Stop-and-go city traffic driving

Driving in dusty conditions (gravel roads, etc.)

Driving at sustained highway speeds during hot weather.


For severe service driving (which is what most of us do), the most common recommendation is to change the oil every 3,000 miles or six months (which ever comes first). This is especially important on older, high mileage (over 100,000 miles) engines.

For maximum protection, many people change their oil every 3,000 miles or three to six months regardless of what kind of driving they do. But some would say this is excessive maintenance and wastes oil. Changing the oil every 3,000 miles is probably NOT necessary on a new low mileage vehicle, especially if the vehicle is driven more than 10 miles one-way daily or is used primarily for highway driving or long distance commuting.

A newer engine with little or no wear can probably go 5,000 to 7,500 miles between oil changes with no harm. But in my opinion, pushing the oil change interval beyond 7,500 miles is asking for trouble, especially if an engine has more than 75,000 miles on it, or it operated under "severe" conditions as described above. Several vehicle manufacturers (Chrysler and Toyota) who have recommended longer service intervals have run into problems with sludge forming inside some engines, causing expensive damage.

As an engine accumulates miles, blowby increases. Combustion gases leak past the rings (blowby). This allows more unburned fuel and moisture to enter the crankcase. Fuel dilutes the oil, and moisture promotes the formation of acids and sludge. So if the oil is not changed often enough, you can end up with accelerated wear, oil sludging and possibly a premature engine failure!

To find out what ASE certified Master Technicians say about oil change intervals, Click Here.

OIL REMINDER LIGHTS

General Motors and a number of European vehicles have done away with recommended oil change intervals altogether and now use an "oil reminder" light to signal the driver when an oil change is needed. On some of these (Volkswagen, Audi, Mercedes Benz, BMW and Volvo), a scan tool or a special service tool is required to reset the oil service reminder light. On others, there is a manual procedure for resetting the oil reminder light.

DO NOT IGNORE THE LIGHT! When the light is on, it is time to change the oil.

The oil reminder systems estimate oil life based on engine running time, miles driven, ambient temperature, coolant temperature and other operating conditions. On some of these vehicles, the light may not come on until 10,000 miles or higher! But keep in mind that most of these engines are factory-filled with higher quality synthetic oil, so be sure to replace same with same when the oil on these engines is changed if you are going to rely on the oil reminder light alone rather than a mileage/time interval.


OIL ANALYSIS

One way to know for sure when the oil needs to be changed is to have the oil analyzed at 3,000, 5,000, 7,500 or 10,000 miles. Many fleets do this to optimize their oil change intervals. A small sample of oil (3 to 4 oz.) is taken from the engine, sealed in a bottle and mailed to a laboratory for analysis. The lab runs a series of tests to determine the properties of the oil and the contaminants that are in the oil. A report is then mailed back with a recommendation as to whether or not the oil is still good.

Having your oil analyzed is not something you need to do all the time. Checking it once or twice should help your determine the optimum oil change interval for the type of driving you do. The cost for oil analysis is usually less than $25, and there are a number of companies who offer such services: Blackstone Laboratories, Oil Analyzers Inc., Insight Services and others.

NEW OIL MONITORING TECHNOLOGY

The latest technology for letting you know when your oil needs to be changed is electronic sensing. An oil monitoring technology originally developed for the military called IntelliStick is now available to consumers. The sensor replaces the dipstick and provides real time monitoring of the oil's true condition. This eliminates the guesswork and uncertainty that exists with recommended service intervals or oil reminder lights.

The IntelliStick uses a simple, patented conductivity test that applies low voltage with slow varying waveforms across two sensor arrays. The sensor measures changes in the electrochemical current flow caused by additive package depletion and impurities that accumulate over time in the oil. As more additives are depleted, most notably antioxidants and detergents, the oil's conductivity changes, which leads to a corresponding reduction in the IntelliStick sensor reading.

The IntelliStick has a transponder at the top of the dipstick that communicates with any Bluetooth-enabled PDA, cell phone or laptop so you can check the condition of your oil at any time.

For more information about this new product, visit the IntelliStick website.

WHY OIL NEEDS TO BE CHANGED

Regardless of what type of oil you use (conventional, synthetic or synthetic blend), all motor oils eventually wear out and have to be changed (actually, it's the additives that wear out more so than the oil). As the miles add up, motor oil loses viscosity and gets dirty. The oil no longer has the same viscosity range it had when it was new, and it contains a lot of gunk (moisture and acids from combustion blowby, soot, dirt and particles of metal from normal wear). You can't really tell much about the condition of the oil by its appearance alone because most oil turns dark brown or black after a few hundred miles of use.

The oil filter will trap most of the solid contaminants, and the Positive Crankcase Ventilation (PCV) system will siphon off most of the moisture and blowby vapors, if the engine gets hot enough and runs long enough to boil the contaminants out of the oil. Even so, after several thousand miles of driving many of the essential additives in the oil that control viscosity, oxidation, wear and corrosion are badly depleted. At this point, the oil begins to break down and provides much less lubrication and protection than when it was new.

If the oil is not changed, the oil may start to gel or form engine-damaging varnish and sludge deposits. Eventually this can cause your engine to fail! Oil sludge can damage engine bearings, piston rings, cylinder walls, valve guides and lifters.

[rspi]

Wow, you asked I guess. The most useful information here was the very last sentance. LOL

I alway think that it's better to err on the safe side, and the person that would pay for the repairs if something goes wrong has the last say.

I use full synthetic and plan to change mine every 5,000 miles. I think that's playing it safe. I don't boost (drive hard) daily so I should be fine. I am thrilled that the guy before me (with 188k) was old school and had the oil changed every 3,000 miles, over kill. The compression on the car at 205,000 was still about 176 across the board (spec is 154 to 186). That's a pretty strong motor for over 200k. There is never any smoke out the tail pipe but it does use about 1 quart every 3,000, not a big deal). Doesn't look like the head has ever been removed. I pulled the intake manifold when I did the PCV and the ports were pretty grimy in there. I switched the car to full synthetic and do 5k changes. Beteen 200k and 210k I went 10,000 miles on the oil in 2 months. About 6k of that was straight highway cruising at 70 mph. I also run lucas fuel injector cleaner through the car every 2,500 miles and use Mann filters.

In the 960 I had, I would change it between 5k and 7.5k. It was on full synthetic as well. Having the oil tested would be great. Also, checking compression every 25k to check for a loss there can also tell you about piston ring wear. If you see the #'s dropping by 5 psi you may want to change it more often. I believe these motors can go 500k if the oil is changed often enough.

I think the most dangerous things for older cars is letting them sit. That will build sludge faster than anything. Putting 5,000 mles on a car in 3 years is really bad for it. Just my opinion.

[jimmy57]

Take a map. Draw a dot on where you drive 5 days per week to work or if homemaker draw the dot on the school where you daily deliver your children. Place pencil-tipped divider that has been set to 5 mile scale length with its metal point on the work or school dot. scribe a circle. Set the divider to 10 miles and scribe another circle. Do the same at 20 and 30 mile settings.
If your home is within the 5 mile radius change your oil at 3000 miles, 10 mile- 5000 miles, 20-7500 miles, and 30-10000 miles.
If you crank the car in cold weather and let it idle to warm up then go down 2500 miles.
If you use synthetic oil go up 50% longer.

[erikv11]

...If you crank the car in cold weather and let it idle to warm up then go down 2500 miles.

So you are saying, if you let it idle to warm up then you need to change the oil even sooner?

[jimmy57]

Yes, idling to warm up produces the greatest amount of condensation. The longer it is below temp the longer it runs richer and more fuel dilution into oil too. If you warm up a car because you want heat when you get in then continue. If you are doing because you think it is good for the car IT IS NOT. Crank it, wait a few seconds then drive off nicely and let the engine computer's program do its job to speed warm up. The amount of heat from the little amount of fuel burned idling with no load is not going to warm it up fast and creates condensation and very little crankcase venting activity.

If it's REALLY cold (below 20F) then let it idle 60-90 seconds for oil to become a little less viscous.

[Matty Moo]

A buddy of mine has an 07 Pontiac G6 with 210k on it. Obviously he does mostly highway driving and does 10-15k intervals with mobil-1. Engine is still as quiet as can be.

Amazingly enough, he's also still on the original spark plugs. I told him two years ago to get those taken care of, last week I told him not to bother with them himself.... Take it in and have them deal with it.

[cn90]

Brining back an ancient thread. What interval is everyone doing now?

Me: P2 cars with 2.5T engines > 100K miles. These cars need 1 qt of oil added every 1,000 miles or so...

- Synthetic 5W40
- Mahle oil filter
- Every 7K miles or so...

[MoVolvos]

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Going back to changing mine less than 5K miles and twice a year unless it's like 3K or so then will procrastinate some. Have started using Rotella T6 15W40 for summer on several cars and the usual T6 5W40 the other half of the year. 15W40 is in the 2012 XC90, 02 V70 XC and 00 S70 SE NA.
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Sitting Down With Lake Speed Jr. - The Truth About Oil Change Intervals and Analysis


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