OCI from Car Owner's Manual vs Haynes Manual

[626LX2.0LATX1998]

First of, I really enjoy this site. Lots of info. Long time reader, first time poster.

Now let me start...

I've been using the Haynes Manual to follow the maintenance of my car 1998 Mazda 626LX 2.0L ATX...
However, I just read the Mazda owner's manual and found out that the oil change interval for my car is 5k miles (8,000km) for severe service and 7.5k miles (12,000km) for normal driving on dino oil.

I just found out i've been wasting money on oil changes cause I've been changing it every 3k miles with dino oil since I got it.

Last December, I switched to synthetic and this oil currently has 3k miles on it and it's Mobil 1 supersyn 5W30, and i planned to use it till 5k miles..

But now that I found out that regular dino oil is expected to stay in my engine for 5k miles under severe service condition from owner's manual, (7.5k miles in normal driving) my plan for 5k extended drain using synthetic doesn't sound extended anymore.

I live in Toronto, Canada so temp can go below 0F. Work is just 10miles and it takes me about 12min drive from home. I drive 80% highway speed 60mph. I do frequent cold starts because I go home for lunch so car sits for 4 hours then I start it again, so approx. 4 cold starts per day with about 30-45sec. warm-up.

Now what is a good extended drain interval with synthetic oil for my car if a dino oil is expected to remain for 5k miles under severe condition?

 

[eljefino]

What does the mazda manual say "severe service" is? You might find that trips longer than or equal to ten miles are "regular service."

Haynes, I'm convinced, cuts and pastes its routine maintenance chapter without careful research. You'll likely find other errors as well.

If I were you, I'd use 5k mile changes with that M1 in the winter and 7500 come summer. Naturally, used oil analysis will tell you for sure.

 

[TomJones76]

If you're using M1, you can probably change your oil once a year and be absolutely fine. With 10 miles to work each way, you're probably driving 12,000 miles per year or less.
I'll disclaim that I'm not practicing what I'm preaching, because I just got my new car.
Here's my prescription, to put your mind at ease:
At 7500 miles, sample your oil and have Dyson labs analyze it. When you do that, ask Terry Dyson if your car will be safe with the oil change interval extended to 15000 miles.
And post the results (but not Terry's comments) in the Used Oil Analysis forum here. We enjoy reading them.

PS- I just realized shipping from Canada to the US on a UOA might be annoying. If it is, find a Canadian lab (preferably a site sponsor) and have them analyze it, making sure to run the TBN (it might cost extra.) *THEN* have Terry analyze it.

Here's a fun link discussing different theories on oil change intervals:
http://neptune.spacebears.com/cars/stories/interval.html

Here's a fun link where a guy actually ran Mobil 1 for a very long time:
http://neptune.spacebears.com/cars/stories/oil-life.html

[ February 24, 2005, 07:47 PM: Message edited by: TomJones76 ]

 

[HerkyJim]

Sounds like pretty severe service to me, so I'd change it every 60 days or so and use Walmart 5-30 and new filter every other change.
My $0.02

 

[bretfraz]

The only way you will know the true answer to your question is to run the current oil to a certain mileage (say... 5000 miles), drain, and send in for analysis. At that point you'll have a good idea of how far to run with that particular oil. From there you can decide how far you want to stretch oil change intervals. One of the primary benefits of full synthetic oils are extended drain intervals. If that's your new goal with this car, an analysis or two will let you know if you're on the right track.

 

[TC]

"Car Owner's Manual vs Haynes Manual"

In general, aftermarket manuals are good for generalities, but cannot always be trusted for specifics (such as specs and procedures) which change with each engine, model, or year. Other than factory technical service bulletins, the owner's manual is the closest thing you'll have to a "bible." Whether one chooses to believe or follow the manual is a different story, but it's the most accurate info you'll get from the factory, topped only by updated TSBs.

 

[srivett]

Haynes manuals aren't very good and from what I've seen Chiltons are evey worse. I would try to get an OEM manual or an OEM approved manual.

Steve

 

[626LX2.0LATX1998]

Well as using dino, I already know that it doesn't flow very well even in -6C because last december at that temp. when I changed to M1 5W30, as I was transfering the old oil (Castrol GTX changed after 3k) from the catch tray to the container, the oil hardly flowed. It was pretty thick after being left overnight in the catch tray.

So I decided to go synthetic hoping to have extra protection in winter and also to extend the OCI. But if the OEM Mazda manual says that a dino oil can actually stay in my engine for 5k miles under severe service, then I don't know if I made the right decision to use synthetic.

UOA's are hard to find in canada, unless someone from here can suggest someone who does it for less than price of 4L of M1.

Also, I am using fram filter, with the black grip on top from Walmart/Canadian Tire (that's the only brand that fits my car in that store), hoping to change the filter easily. If I remove the filter, I expect the oil to spill out. Is there an easy/quick way of taking off the filter without leaking oil?

 

[Grossomotto]

quote:

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Is there an easy/quick way of taking off the filter without leaking oil?

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Ziplock bags work the best, IMHO. Just get ones big enough to hold your filter. I'm sure you can figure out the rest!

 

[rpn453]

quote:

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Originally posted by 626LX2.0LATX1998:
If I remove the filter, I expect the oil to spill out. Is there an easy/quick way of taking off the filter without leaking oil?

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Funny thing about that engine/filter: my ex-girlfriend had an MX-6 with the same engine and the first time I did an oil change I was shocked when I took the filter off and, not only did it not drip, it was empty. I figured that either the ADBV had failed or Purolator Premium Plus filters were no good in the ADBV category. So, even though she had a bunch of new Purolators that a friend who used to own a 626 gave to her, I bought a NAPA Gold filter (Wix). It did the same thing on the next oil change.
In other words: don't be surprised if this happens. Or maybe there's just something strange going on with her car?

BTW, I'd go with Mazda's OCI recommendation over Haynes'. I trust their engineers and, as eljefino mentioned, the Haynes recommendation is simply a conservative "cut-and-paste" one.
Personally, I'd use the severe service schedule for winter and non-severe for summer.

[ February 26, 2005, 12:55 PM: Message edited by: rpn453 ]