Why don't owner's manuals specify the oil type

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If the OM recommendation is 0Wx20, I assume it only comes in synthetic so there is no ambiguity ...
However, I have seen many owners manual that recommend 5Wx20, 5Wx30, 10Wx30, 10Wx40 and to change the oil after x many miles without specifying the oil type (conventional/dino vs. Synthetic or syn-blend).

Do manufacturer specify the oci (x miles) considering the lowest performing oil (i.e. dino) available on the market? or do they think there is not a huge difference between conventional and synthetic
shocked2.gif
 
In the absence of other requirements like VW502, LL01, Dexos1 etc my guess would be the recommendation comes from the minimum requirements for that lubricant as the API spec is usually stated as well. For example my 2004 Lexus required API SL or better in 5w30. New cars are the same, specify a viscosity and spec, again in the absence of other requirements.

It's been shown over and over again that at reasonable intervals that a conventional lubricant performs admirably. My 4Runner has been run on conventional 99% of it's life and is still trucking along at 342,660 miles, it currently has conventional in the sump.

In the absence of a manufacturer spec I'd be comfortable going the recommended interval on Super Tech conventional if it existed in the required/recommenxed viscosity.
 
All SN/SN+ 5-20 and 5-30 oil is semi-synth and pretty good. There's some interesting comment on Blackstone's web site stating that they can find no real wear difference in various brands of oil-- cheap or expensive. In other words, for most cars, ST dino works as well as Royal Purple.
 
Originally Posted by OilUzer


Do manufacturer specify the oci (x miles) considering the lowest performing oil (i.e. dino) available on the market?


Yes, absolutely.

Military repair manuals are written to the "8th grade level" not because everyone who comes in is at that level....

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.
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But...... there's always that ONE GUY (or girl)
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So, they have to build the car and specify oils to the "lowest common denominator" of "mankind"
 
Originally Posted by csandste
Blackstone's web site stating that they can find no real wear difference in various brands of oil - - cheap or expensive. In other words, for most cars, ST dino works as well as Royal Purple.


Most cars.

Some vehicles that do a lot of heavy towing, very cold starts, etc. can see some benefit from running a high quality synthetic.


But, your Grandma's Hyundai Sonata in Kentucky likely will never, ever tell the difference.
 
I never saw an owners manual with a oil recommendation on viscosity alone. A lot will have a manufacturer spec. If not, they likely will say to meet a API or ILSAC. The Toyota I have just says ILSAC GF-5 0w20. So basically I just need to use a 0w20 that meets ILSAC GF-5 or later. Most 0w20 is sold in full synthetic but there are a few synthetic blends out there. 0w20 will require better base stocks to make vs. 5w20 and that is probably why Toyota specs 0w20 with a 10k OCI.
 
Originally Posted by NH73
... The Toyota I have just says ILSAC GF-5 0w20. So basically I just need to use a 0w20 that meets ILSAC GF-5 or later. Most 0w20 is sold in full synthetic but there are a few synthetic blends out there. 0w20 will require better base stocks to make vs. 5w20 and that is probably why Toyota specs 0w20 with a 10k OCI.
My Toyota, likewise. They also say you may use a conventional 5W-20 if 0W-20 is unavailable, but must replace it at half the normal change interval. In some contexts, they omit the "conventional" adjective, in otherwise similar statements. What's conspicuously missing is clarification as to whether synthetic 5W-20 of the same (apparent) quality as a manufacturer's 0W-20 is equally OK for the same change interval. I'm betting it is, although I'm technically violating their prescription by using 5W-20.
 
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Originally Posted by CR94
Originally Posted by NH73
... The Toyota I have just says ILSAC GF-5 0w20. So basically I just need to use a 0w20 that meets ILSAC GF-5 or later. Most 0w20 is sold in full synthetic but there are a few synthetic blends out there. 0w20 will require better base stocks to make vs. 5w20 and that is probably why Toyota specs 0w20 with a 10k OCI.
My Toyota, likewise. They also say you may use a conventional 5W-20 if 0W-20 is unavailable, but must replace it at half the normal change interval. In some contexts, they omit the "conventional" adjective, in otherwise similar statements. What's conspicuously missing is clarification as to whether synthetic 5W-20 of the same (apparent) quality as a manufacturer's 0W-20 is equally OK for the same change interval. I'm betting it is, although I'm technically violating their prescription by using 5W-20.


Interesting!
My Toyota says sae 0wx20 must be used but if sae 0wx20 is not available, sae 5Wx20 maybe used. However it must be replaced with 0Wx20 at next oil interval. There is no mention of reducing the interval or using a synthetic 5Wx20. Since 5Wx20 can be syn-blend and sounds like you can even have a conventional 5Wx20 as well.

Besides there are many owner's manuals that don't mention anything about syn vs. dino.
Maybe 0Wx20 or d1g2 or some other specs (BMW, etc.) forces the use of synthetic but there are other cars that just recommend the grade and api spec and nothing else.

I think they should specify the oci as follow if they are recommending any grade that can be dino or synthetic:
  • x miles with conventional
  • x+2000 miles (for example) with synthetic
 
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Originally Posted by OilUzer
If the OM recommendation is 0Wx20, I assume it only comes in synthetic so there is no ambiguity ...
However, I have seen many owners manual that recommend 5Wx20, 5Wx30, 10Wx30, 10Wx40 and to change the oil after x many miles without specifying the oil type (conventional/dino vs. Synthetic or syn-blend).

Do manufacturer specify the oci (x miles) considering the lowest performing oil (i.e. dino) available on the market? or do they think there is not a huge difference between conventional and synthetic
shocked2.gif



Its real simple.

It doesnt matter if the oil is synthetic, conventional or semi syn.

and why on earth do you call dino oil the "lowest performing oil available on the market? ? Do you know some conventionals beat synthetics when it comes to wear?
$2. a quart oil of the same ratings are just as good as $7 a quart oil.

All oil of the same ratings are equal, there is no proof one is better then the other.
Sounds like a bit too much BITOG or you have been listening/reading the marketing material of too many oil products.

Oil is oil, ratings such as API are ratings, whatever gives one the idea that one is better then the other is marketing.

(just talking here)
 
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would you still take conventional over synthetic if price was not a factor?
 
Originally Posted by OilUzer
would you still take conventional over synthetic if price was not a factor?


If I maintain the 10k mile oci, no, I'll take synthetic all the time. All the major brand synthetics have shown they can easily go 10k miles in a well maintained car. Also synthetic oil has come down in price so much, for a 5 quart jug, the price difference is as little as $5 esp if you shop Walmart.

I'm sure there are conventional or blends that can go 10k OCI. I don't know much about them and picking a synthetic that's on sale is much easier for me.

Good luck.
 
Originally Posted by OilUzer
would you still take conventional over synthetic if price was not a factor?


I'm ancient and live in a condo that doesn't allow working on your car, so I gotta go to an oil change place. I get a $10 VWB oil change (with tax and fees it's more like $17). Occasionally there's a $10 extra for MaxLife and if available I'll use that. Usually the coupon says $10 off for MaxLife (their only blend) or syn. That's $40 or $50. I notice that 5 quart bottles of VWB and MaxLife costs the same at Wally World.

So, if I changed my own I'd be spending the few bucks extra for synthetic. At triple the price for an oil change, it's not worth it.
 
Originally Posted by OilUzer
Originally Posted by CR94
Originally Posted by NH73
... The Toyota I have just says ILSAC GF-5 0w20. So basically I just need to use a 0w20 that meets ILSAC GF-5 or later. Most 0w20 is sold in full synthetic but there are a few synthetic blends out there. 0w20 will require better base stocks to make vs. 5w20 and that is probably why Toyota specs 0w20 with a 10k OCI.
My Toyota, likewise. They also say you may use a conventional 5W-20 if 0W-20 is unavailable, but must replace it at half the normal change interval. In some contexts, they omit the "conventional" adjective, in otherwise similar statements. What's conspicuously missing is clarification as to whether synthetic 5W-20 of the same (apparent) quality as a manufacturer's 0W-20 is equally OK for the same change interval. I'm betting it is, although I'm technically violating their prescription by using 5W-20.


Interesting!
My Toyota says sae 0wx20 must be used but if sae 0wx20 is not available, sae 5Wx20 maybe used. However it must be replaced with 0Wx20 at next oil interval. There is no mention of reducing the interval or using a synthetic 5Wx20. Since 5Wx20 can be syn-blend and sounds like you can even have a conventional 5Wx20 as well.

Besides there are many owner's manuals that don't mention anything about syn vs. dino.
Maybe 0Wx20 or d1g2 or some other specs (BMW, etc.) forces the use of synthetic but there are other cars that just recommend the grade and api spec and nothing else.

I think they should specify the oci as follow if they are recommending any grade that can be dino or synthetic:
  • x miles with conventional
  • x+2000 miles (for example) with synthetic
Owner Manual are what they are. My guess they don't do that is so not to add to confusion. No doubt a synthetic 5w20 will be just as good as a 0w20. Al that as long as extending OCI's can be done with UOA's.
 
My 2018 Grand Caravan says conventional 5w20 oil but you can use synthetic 5w20 just don't go over 8k or one year same as conventional even giving Pennzoil 5w20 conventional or Gold as examples. Will run conventional.
 
Originally Posted by OilUzer
If the OM recommendation is 0Wx20, I assume it only comes in synthetic so there is no ambiguity ...
However, I have seen many owners manual that recommend 5Wx20, 5Wx30, 10Wx30, 10Wx40 and to change the oil after x many miles without specifying the oil type (conventional/dino vs. Synthetic or syn-blend).

Do manufacturer specify the oci (x miles) considering the lowest performing oil (i.e. dino) available on the market? or do they think there is not a huge difference between conventional and synthetic
shocked2.gif



Except in some specific cases of specs requiring a Dino vs syn the OM's just spec grade and minimum API designation (SN, etc.)

That way their arses are covered when Joe Schmo puts in cheap dino from a quickie lube but the engine is still happy when a BITOG'er used a nice Syn.
 
Last edited:
Originally Posted by dtownfb
Originally Posted by OilUzer
would you still take conventional over synthetic if price was not a factor?


If I maintain the 10k mile oci, no, I'll take synthetic all the time. All the major brand synthetics have shown they can easily go 10k miles in a well maintained car. Also synthetic oil has come down in price so much, for a 5 quart jug, the price difference is as little as $5 esp if you shop Walmart.

I'm sure there are conventional or blends that can go 10k OCI. I don't know much about them and picking a synthetic that's on sale is much easier for me.

Good luck.



Depending on useage synthetics can go for a lot less miles and conventional can go for a lot more. The majority are blends today.
 
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