Justification for the 3000 mile oil change

[pitzel]

http://www.noln.net/columns/1-05/chevrontexacojan05.html

quote:

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A good rule-of-thumb for determining engine oil life is to look at the point where the acid and base number curves cross. In my case, the crossover point in Figure 2 occurs at about 3,000 miles. (Gee…maybe there is some science behind the recommended drain interval of 3,000 miles!)

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Should be noted that the oil started at a TBN of 6, so probably the cheapest XW-30 Havoline Dino was involved here. The article also doesn't provide really any evidence that a drain interval of 12k miles with ChevronTexaco's oil isn't appropriate, and I feel it is fairly weak in impugning that a 3000 mile oil change is necessary. Interesting, eh, even some of the industry propoganda is getting fairly weak.

 

[Steve S]

For some people, that is the only way the car will get fluids checked and tires aired.

 

[Jelly]

I do a 4,000 mile OCI, so I don't believe I can say too much...

 

[doitmyself]

This is a carefully worded advertisement for the quick oil change facilities to promote 3K OCIs.

It throws in some graphs and data that appear to be o.k., then the text is carefully worded to support the 3,000 mile OCI, without entirely throwing out longer OCI's.

"Figure 2 shows that there is still a good amount of base reserve remaining after 3,000 miles. If a driver wanted to push a drain, they could go as long as 6,000 miles without any serious detrimental effects from oxidation."

It concludes with:"it cheap insurance to do frequent changes".

"So what’s the bottom line when your customers ask you how often they should change their oil? My own personal experience (which is backed up by numerous scientific studies) is that engine oil continuously loses its effectiveness as mileage increases. The standard recommendation of 3,000 miles is certainly a good one. It may be possible to extend this interval, especially if a motorist uses a high quality oil and does not drive under severe conditions. However, more (rather than less) frequent oil changes are certainly a very cheap form of insurance when you have a large investment in your vehicle at stake."

He doesn't elaborate how a longer OCI can also be a good recommendation, depending on the circumstances.

The average consumer will be convinced by this "scientific" data that 3,000 mile OCI is always best.

 

[T-Keith]

Looks like he's using the same critiria as BOTIG uses for extended drains. Why does he end up with a different conclusion?

 

[pitzel]

quote:

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Originally posted by T-Keith:
Looks like he's using the same critiria as BOTIG uses for extended drains. Why does he end up with a different conclusion?

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Loyalty to his employer? Self-preservation?

 

[Doug Hillary]

Hi,
again IMHO this is a continuance of careful and probably justifiable misinformation that "fails safe" for Mr Average Motorist

As an example Porsche have for nearly three decades advocated OCIs of around 20k kms (12k miles) or one year in normal use with "Approved" MINERAL oils (and the same with Approved synthetics). Many Porsche Service Providers promote 5k (3k) OCIs even when using M1 0w-40 and charge accordingly. A waste of a great resource is being perpetuated here. These engines handle the factory limits with ease of course as long as Approved oils are used

Detroit Diesel-MTU in OZ recommended OCIs of 20k kms for their Series 60 engines (400+ hp) commencing in 1992 and when using CG-4 oils. I started UOAs and a semi-synthetic CG-4 HDEO and settled on 40k kms with no interim filter change. Later when using a fully synthetic CH-4 HDEO (and after installing a centrifuge by-pass filter) I settled on 100k kms OCIs and have used this parameter for nearly a decade. This did NOT include an interim filter change during the oil use period. I used random UOAs thereafter and the longest drain interval was @ 130k kms - the oil was still usable. The average OCI of all engines has been @ 90k kms. A recent tear down inspection of one engine at 1m kms (620k miles) showed virtually no wear on major wearing components and they were reusable including all valve train components. The cam and crank bearings were like new and no signs of corrosion etc was evident

The DD-MTU minimum for TBN of 1 (D4739) or 2 (2896) was always observed along with the maximums for Iron @ 150ppm, Copper @ 30ppm. Mobil's soot limit of 3.5% (DD-MTU's was 3) was used and their viscosity limits observed at all times
We never changed oil simply because these limits were met and we monitored other condition factors like fuel, coolant etc. Of course the average top up rate of 6k kms/litre was factored in to the UOA analysis
The lowest TBN recorded was 2 (D4739) and the highest TAN was 7.7 both reached at about 90k kms during one OCI.
The highest Soot level reached during an OCI was 3.6% and the Iron was @ 161ppm at that stage - this was at 106k kms when the oil was changed

These sorts of levels have never been reached in any petrol engines owned by me even at OCIs of 20k kms and over

So IMO the 3k OCI is a fail safe for Mr Average Motorist - tragically it is simply a waste of a valuable resources and money in many cases

Regards
Doug
MY02 Subaru Outback 2.5 manual (Delvac 1)
MY98 BMW Z3 2.8 manual (Delvac 1)
MY89 Porsche 928 S4 Auto (Delvac 1)

 

[ULVER]

Three thousand mile OCI's are the only sure way, to make sure you are protecting your vehicle's engine. Stop by, and have one of our felons...ah, I mean fellows change yours today.

Sincerely,
Al Snowya

President
Jiffy Lube

 

[Mike_dup1]

3000 mile Oil changes are very profitable.

There is a Pennzoil quick lube place here up for sale, the realator is advertising the gross sales per year are in the $250,000 range and thats in a small market of about 45,000 pop. And there are 2 other quick lube places in the same area.

I use to have my gov't truck serviced at one and only because they were Wheels Aprroved account that did not require a purchase order etc. We were required to service at only 5000 mile min. intervals and no time limits. This shop constantly tried to talk me into doing it every 3000 miles or 3 months. I got to know the manager over the years and he would always say, we ain't making any money off this guy.

[ February 11, 2005, 09:25 PM: Message edited by: Mike ]