Oil change frequency?

[Wade Lippman]

Our new Mazda CX9 recommends changing oil every 7,500 miles, or 5,000 miles for rough use. The dealer said that around here (WNY) all use is considered rough use because of the cold and salt; so they say to change every 5,000 miles.

The manual calls for 5w20. My wife went into for an oil change and her recollection was that that it needed synthetic 5w20, even though I told her yesterday that was not what was required; but of course she got synthetic.
So my question (at long last)... As long as we paid through the nose for synthetic, can we stretch out the next oil change to 7,500 miles? Isn't synthetic supposed to last longer?

And a second question... I was reading about this and an oil company(Amsoil,whoever they are)says that the recommendation for 5w20 is so that the car company can claim another 0.1mpg in their mileage reports, and that 5w-30 is actually better for the engine.  Sounds like nonsense to me, but the oil company also sells 5w-20, so it is hard to see why they would lie. Whatcha think?

[David Weaver]

In terms of the amsoil claim, what car in the last 15 years has worn out because of engine wear? I haven't had any. It's everything else on the car that will make you go broke.

I would imagine that 7500 miles on 5w-20 synthetic will be fine as long as you have a decent filter. Whether or not mazda will try to hold you up for some sort of warranty claim if they gave you a dud engine is another question.

I always change my oil myself, I always change it with synthetic - it usually costs me about $30-$45 depending on what car and what kind of sale deals I can find on oil and good filters. I guess the dealers probably nail you if you get synthetic from them.

Anyway, the chance of a warranty claim where:
* something happens mechanically to the engine that has nothing to do with oil, but...
* the manufacturer tries to claim that you went too long between changes

That's what would be my concern. When I change oil at 5k miles (here in the w pa hills), it's probably like most people changing oil at 7500 and my oil still has life in it when I change it (it's full synthetic, as I mentioned). When I lived in central PA, I always got mileage around the highway rating for overall experience. Where I am now in the hills and burbs, the mileage is at the city rating or below - my 5000 miles aren't dirty miles, but they are hard miles compared to what cars get in most places (my same car that gets less than city mileage here will go past its highway rating as soon as we get it out on the open highway on a long trip).

[Tom M King]

All our vehicles get the same schedule, as they all have had for decades. I run full synthetic, and change it every 10,000 miles. When I break in a new vehicle, for the first 10,000 miles I run dino, and change it at 1, 2.5, 5, and 7,500, and switch to Synthetic at 10,000. I know the manufacturers have a different suggested schedule, but my plans for longevity are different from theirs. Any vehicle we've run since the mid '80s has still had nearly new compression at 200,000. We buy new, and drive them until they drop, or get so tired of it that someone else drives it until it drops.

[Howard Garner]

Do what the owners manual specifies.
Many of today's specify a 10k change interval and most also specify a full synthetic.

My 2005 VW Diesel specifies 10k, and a certain VW full synthetic oil spec.

Howard Garner

[Myk Rian]

Check the oil at 5k, and if it's still fairly clear on the dipstick and doesn't smell burned, leave it and check again at 6k.

[Brian Elfert]

The majority of drivers should go by the severe duty cycle for oil changes. It is only if you travel long distances on the highway most of the time would you qualify for the normal cycle. My Dodge Grand Caravan has an oil life monitor. It does work because when I spent a week making many short 1/4 to 1/2 mile trips at 15 MPH the "oil change required" message came on after only 4,000 miles. I typically get between 7,500 and 8,000 miles per oil change.

My brother bought a 50,000 mile car in the late 80s. Engine blew at under 60,000 miles and was full of sludge. Mechanic thought the first owner never changed the oil. It cost him a bunch for an engine.

[Curt Fuller]

I bought a new 2013 Toyota Highlander in August. They come with free service for the first 2 years or 25,000 miles at 5,000 mile intervals. I just took it in for the first service at 4800 miles (we don't drive much) and was surprised that it was only a check up, top fluids, rotate tires, etc. No oil change. Oil change intervals are 10,000 miles for this car, according to Toyota. It is full synthetic oil. Our previous car was a 2004 Highlander and the recommended oil change interval was 5,000 miles. The service light would come on at around 4,500 miles as a reminder. I've never used synthetic oil, but I changed my own oil on the 2004 Highlander and my 2000 Tacoma as soon after 4,000 miles as I can get to it and the oil still looks almost like new even after 14 years. Not sure what they're doing with these newer cars but they go a lot farther between changes than older cars. Of course, places like Jiffy Lube and other oil change places still recommend 3,000 because they're in the business of changing oil.

[George Bokros]

I change at six months or 4K miles which ever comes first. Now that I am retired 6 mo comes first. In the two years since I retired I put only 8K miles on my Ranger. On the other car in 2 1/2 yrs we put 11K miles and it gets the six month treatment also. I use Motorcraft Syn blend oil in both cars since it is recommended by Ford.

When I drove my truck for trans to work oil was changed every 10 weeks since I was driving 3,500 miles in 10 weeks. Clean oil is the lifeblood of the engine.

George

P.S. Yea I am old school.

[Andrew Fleck]

The majority of drivers should go by the severe duty cycle for oil changes. It is only if you travel long distances on the highway most of the time would you qualify for the normal cycle. My Dodge Grand Caravan has an oil life monitor. It does work because when I spent a week making many short 1/4 to 1/2 mile trips at 15 MPH the "oil change required" message came on after only 4,000 miles. I typically get between 7,500 and 8,000 miles per oil change.

My brother bought a 50,000 mile car in the late 80s. Engine blew at under 60,000 miles and was full of sludge. Mechanic thought the first owner never changed the oil. It cost him a bunch for an engine.

I'm not sure I agree with that. Severe duty is just like it sounds, not normal day to day driving. Street racing, off roading, towing, etc....that is severe duty. I change my oil every 5000 because that is what the manual calls for in normal conditions. Changing every 3000 miles or whatever the manual calls for in severe conditions is a complete waste of money for somebody who just drives normally.

[George Bokros]

Short distance driving is considered "severe service" also as the moisture does not get evaporated from the crankcase and that causes acid to develop in the oil which ruins bearings and cylinder walls. Short 10 minute 3 mile drives to the local store is very harmful.

George

[James Conrad]

The problem with long oil changes, has less to do with oil breakdown when it comes to synthetics, but the filter. My understanding is that there are not any filters currently made for the consumer market that can go 10,000 miles. I can't imagine waiting 10k for a first oil change on a new car. An oil and filter change every 5k is pretty cheap insurance.

[Kev Williams]

Our motorhome has an 8.3 Cummins diesel in the back, the thing weighs like 23,000 lbs and has a GVWR of nearly 30,000 lbs, it uses 15w-40 NON synthetic oil, and Cummins recommends oil changes at 15,000 miles.

Just for reference... :)

[Mike Henderson]

I went through this with my dealer. He claimed that around here, because of the freeway driving, we should change oil based on the severe service interval. I told him that if driving on the freeway is "severe service" then what is "normal service".

It's clear that the dealer just wants to do more service on your car. Dealers make a lot of money on service these days.

I'd follow the "normal service" interval. And unless you just want synthetic oil, I'd go with petroleum based oil.

Mike

[John Sanford]

Go by the manual. If you religiously stick to the manual, then good ol' fashioned dino oil will be fine. Stretch intervals past the manual, and synthetic starts to show it's advantages. Of course, synthetic won't hurt anything other than your wallet, and it the extra cost may be worth the peace of mind for you. On the difference between the car company's and the dealer's recommendation, remember, its the MANUFACTURER who is going to have to pay for warranty and recalls. There is no way they're going to underspec their published service intervals, talk about an ambulance chaser's field day. And no, normal Joe American usage is NOT severe duty. Severe duty is taxi cabs, police cars, extensive towing, 8-24 hr day delivery usage, etc.

There are several reasons for the longer intervals. Better manufacturing tolerances for the engines in the first place. Better heat management in the engine. Better metallurgy. Better lubrication system. Then, add in the better oil chemistry AND most importantly, LARGER oil capacities, and voila, longer intervals. Oil change intervals in Class 8 trucks (aka "semis") is 30,000 miles. They're changes are by the gallon, not quart. Volume, it does a lubrication system good.

[Brad Adams]

The oil may make it to 10,000 miles, but the oil filter is the limitation. My neighbor is a Volkswagen mechanic. He says not to go past 5000 miles, as the oil filters have a bypass that goes off when the filter gets plugged. He said he sees more problems with the engines on the cars the oil is changed every 10,000.

[Steve Peterson]

I have a 1999 BMW 323i with an oil change recommendation of 15000 miles. I think I did an extra one at 7500 miles and have stuck with the factory spec ever since. The car has 170K miles and still going strong. Of course, they use full synthetic and good filters.

Steve

[Tom Stenzel]

There are engines with variable valve timing that require 5w-20 to run correctly. Using 5w-30 won't allow the camshaft phasing mechanisms to operate as expected and will trip the service engine light. Yes, the guys at the dealer will know why pretty quick.

I'm not familiar with Mazda engines at all. 5w-30 weight may be fine, it may not. Synthetic may be required, it may not.

Myself I'd follow the manual until the warranty was up. Also look in the manual to see what THEY describe as severe duty.

-Tom

[Phil Thien]

It's clear that the dealer just wants to do more service on your car. Dealers make a lot of money on service these days.


Pretty much what I've observed, too.

[Doug Carpenter]

I'd just be happy that your wife cares about the oil at all! My wife shrugs it off when ever mentioned. I get that it is my thing to deal with but I swear sooner or later we'll lose a car over it. lol

[Brian Elfert]

I had a VW Golf TDI. VW required synthetic diesel oil and the oil change interval was 10,000 miles. The oil filter is a cartridge type and not spin-on. I had no qualms about a 10,000 mile oil change since the manufacturer specified it. My 2012 Dodge Grand Caravan has an oil life monitor. The manual says to change the oil when indicated, or every 8,000 miles if the oil life monitor has not activated. I usually get between 7,000 and 8,000 miles before the "oil change required" message shows up.

[Jim Becker]

I go by the manufacturer's service intervals in the manual. For my 2012 Grand Cherokee Summit, that is 8000 miles. (MY14 is 10K miles) I do use synthetic oil and have done so for many years.

I question the dealer stating that you should use the lower interval because of "cold and salt". Those are not normally listed as "rough use" things by the manufacturer. Heavy towing, substantial off-road use, taxi service, etc., generally shift things to the lower interval under manufacturer specifications. Your owner's manual will tell you what is considered "rough use" for your particular vehicle. In my experience, dealer service departments typically push for lower fluid change intervals because of...profit. We had one local dealer that pushed so hard on that point that we have never returned to them for that vehicle and just use a local independent shop for everything except warranty work.

[Bob Turkovich]

I go by the manufacturer's service intervals in the manual. For my 2012 Grand Cherokee Summit, that is 8000 miles. (MY14 is 10K miles) I do use synthetic oil and have done so for many years.

I question the dealer stating that you should use the lower interval because of "cold and salt". Those are not normally listed as "rough use" things by the manufacturer. Heavy towing, substantial off-road use, taxi service, etc., generally shift things to the lower interval under manufacturer specifications. Your owner's manual will tell you what is considered "rough use" for your particular vehicle. In my experience, dealer service departments typically push for lower fluid change intervals because of...profit..

Ditto to Jim's advice. Always follow the manufacturer's recommendations...always. They aren't written in a vacuum.

The primary deteriorating factor for engine oil (and transmission fluid for that matter) is temperature. The "change oil" light algorithms on most recent vehicles are primarily based on oil time@temperature histograms stored in the engine controller. Obviously, heavy use such as trailer towing and stop-and-go driving will fill in the histogram quicker. Cold & salt should have no effect on oil longevity.

I also recommend never putting any additives/supplements into your vehicles' fluids (at least while it is still on warranty) as there is no way the OEM's can verify every additive out there and there is no way the additive supplier can confirm full material compatibility with every manufacturers' system. (Some additives may offer help to some vehicles. You just can't be sure which ones.) The only safe additive I can recall (pre-retirement) is Chevron Techron for fuel injector cleaning as all the major injector suppliers had verified compatibility with their injector interior components.

Anything else recommended by the dealer is purely for profit.

[Stan Calow]

My dealer's mechanic refused to change the oil at 3,000 on my new truck saying the manufacturer recommended 10K and they stood by that.