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Oil questions?

Okay, so my folks and siblings kinda look to me for car advice. So far, this is what I’ve told them about oil. Was wondering if the advice is on the mark or not (as I’m not really the expert they make me out to be.)



1. Don’t go any lower than 5w-30. I’ve felt that 5w-20 and such is mainly for the company’s benefit: the marginally better MPGs allow them to sell comaparatively more of expensive, larger, (until recently) more profitable vehicles.



2. Don’t use (non-syn) 0w oil. This because 0w-30 is basically 0 weight at heart that just plays “dress up” as 30 weight due to additives. Should you ask too much of it, it will revert to 0w, generally at the worst possible time. My advice is 5w (winter) and 10w (summer); maybe even 10w (winter)–with warm-up–if you really “beat” on your car.



3. Oil change 3500 (DIY) or 5000mi (mechanic). This is because there’s certainly “diminishing returns” with increasing the frequency of changes; the point at which the add’l changes cost more than the corresponding savings on wear. Since DIY changes are about 1/2 price, more frequent changes make sense; more costly changes make the equilibrium point higher.



4. Additives: save your money (1 possible exception). That exception being zinc/phosphorus additives. Everything else is stuff that the oil companies choose not to include; ZDDP is stuff that they’ve been told not to use. I’ve just run oil w/o Z or P additives; going to have it analyzed for wear metals in comparison before making a recommendation one way or another.

There is a far simpler and better set of instruction.  

[b] Read the owner's manual [/b] 

Not all engines are the same, they have different needs.  Whatever the owner's manual says works best.  We all tend to think in terms of what yesterday's cars needed, but today's cars are far different. 

 Following the instructions in the owner's manual is far better.  Don't cheat and just look at the general instructions however.  Read the whole manual including the part about checking oil yourself regularly and the part about severe driving conditions.  

I’ve felt that 5w-20 and such is mainly for the company’s benefit:

In many modern cars it is needed to get oil to some of the close tolerance parts.

Don’t use (non-syn) 0w oil. This because 0w-30 is basically 0 weight at heart

 I don't believe you will find a non-synthetic oil recommended by a manufacturer that would be a 0W oil.  

[i] Oil change 3500 (DIY) or 5000mi (mechanic) [/i] 

Change it as recommended in the manual.  Modern oils will last far longer today than oils once did.  There have even been some evidence that changing too soon can increase engine wear. 

[i] Additives: save your money [/i] 

Good advice.  I suggest you stop there. 

In a old engine that is leaking, you might benefit with an oil designed for high mileage engines as it will have additives to swell the seals and might let you get a few more miles out of the old girl.

Your folks and and siblings need better advice, and it can be found in the owner’s manuals of their vehicles.

They should use whatever oil is recommended, and change it at the frequencies recommended. If the manual calls for 5w20 or 0w30 that’s what should be in the engine, and the same oil is good all year round. They don’t need winter and summer oil. Stop thinking you know more than the factory engineers.

No additives. Ever. Period. No exceptions.

They may not even need the owner’s manual, chances are it will say right there on the oil cap what is needed for that engine. Exceptions will however, be in the owner’s manual. For example, in my car it says “SAE 5W-30” on the cap but in the owner’s manual it states that 10W-30 may be used if it doesn’t get below 20F in the winter. It will also specify if synth can be used, and the specs for that engine oil.

"1. Don’t go any lower than 5w-30. I’ve felt that 5w-20 and such is mainly for the company’s benefit: the marginally better MPGs allow them to sell comaparatively more of expensive, larger, (until recently) more profitable vehicles. "

   Not necessarily today's engine have closer tolerances and require a thinner oil. It's been proven that 5W-20 oils do everything 5W-30 oils do, only better. 

"2. Don't use (non-syn) 0w oil. This because 0w-30 is basically 0 weight at heart that just plays "dress up" as 30 weight due to additives. Should you ask too much of it, it will revert to 0w, generally at the worst possible time. My advice is 5w (winter) and 10w (summer); maybe even 10w (winter)--with warm-up--if you really "beat" on your car."

  0W-30 oils may be useful in very cold climates. Changing between a 5W and 10W depending on season is trival at best. But if it makes you feel better, it probably won't hurt anything

"3. Oil change 3500 (DIY) or 5000mi (mechanic). This is because there’s certainly “diminishing returns” with increasing the frequency of changes; the point at which the add’l changes cost more than the corresponding savings on wear. Since DIY changes are about 1/2 price, more frequent changes make sense; more costly changes make the equilibrium point higher. "

 The car doesn't know or care who changed the oil. With today's modern oils and cars that have oil life monitors, oil changes of nearly 10,000 miles or better are possible. Most people (myself included) usually change the oil around ever 5k though since it's easy and cheap to do so.

“4. Additives: save your money (1 possible exception). That exception being zinc/phosphorus additives. Everything else is stuff that the oil companies choose not to include; ZDDP is stuff that they’ve been told not to use. I’ve just run oil w/o Z or P additives; going to have it analyzed for wear metals in comparison before making a recommendation one way or another.”

 If you have an older classic car , oil with ZDDP is desirable particularly if the car has solid lifters. As far as additives go, most are indeed snake oil. I've had good luck with seafom though.
  1. Don’t go any lower than 5w-30. I’ve felt that 5w-20 and such is mainly for the company’s benefit:

That may be what you felt…but your WRONG. Many engines can NOT tolerate the 5w-30 because of very tight tolerances.

  1. Additives: save your money (1 possible exception).

Show me the ONE additive that will save you money…There isn’t ONE out there PROVEN to save you money. The oil companies choose NOT to include them is because they are NOT needed.

  1. Oil change 3500 (DIY) or 5000mi (mechanic).

HUH…If a mechanic changes your oil it’ll some how last LONGER then if you DIY. This makes no sense what-so-ever. Read the owners manual for oil change intervals. 5k is pretty much the standard. My 98 Pathfinder isn’t burning one drop of oil between the 5k mile oil changes (sometimes longer because my daughter forgets to drive up from Boston when it’s due) and it now has well over 330k miles…

Here is my two cents.

  1. If your owner’s manual says to use 5W-20, use 5W-20. If you don’t have the owner’s manual, refer to the writing on the oil filler cap or the writing on the dip stick.

  2. 0W-anything is usually stynthetic oil used for hybrid engines. If your car recommends 0W-20, there is a reason. Just use what the manufacturer of your car recommends.

  3. The oil change frequency should be the same whether you do it yourself or you pay someone else. If your owner’s manual says 5,000 miles, change it at 5,000 miles. If it has a higher interval, it should depend on whether or not it requires synthetic oil. If your car requires synthetic oil, change it as often as your owner’s manual says to change it. If your car uses normal oil, this is a case where you might benefit from a shorter interval. If your manual says to change the oil every 6,000 or 8,000 miles, you might consider changing it every 5,000 miles regardless of what your owner’s manual says.

  4. Modern oil has its own additives in it already. There is no reason to add more additives, even zinc/phosphours additives. It is a waste of time and money.

Getting a used oil analysis will certainly help you decide what it best for your car, but I am not sure it is worth the trouble.

Where do you guys get this “close tolerance” stuff. I have never seen anything authoritative.

Look at the engine specifications…NOT FROM THE OWNERS MANUAL…The specifications in the shop manual. Compare that to engines 20-30 years ago…MUCH TIGHTER tolerances.

Where do you guys get this “close tolerance” stuff. I have never seen anything authoritative.

Here you go:

http://machinedesign.com/article/optimized-tolerances-make-good-products-better-0307

http://www.avweb.com/news/maint/oil_myths_debunked_197096-1.html

Check out your original post. If it was not your, then it was an amazingly alike, all the way down to the ZDDP.

Lots of comments already.   Most don't seem to agree with your advice.

I am still not buying it. The first piece does not mention lubrication or oil flow in any way. The second piece does not mention oil flow either. I think this is just an urban legend.

I am more willing to believe that using oil of too high a viscosity is more of a problem in OHC engines than in push-rod engines because it starves the top end. In the former engines the need for quick lubrication might be greater for the spinning cam shafts.

I am more willing to believe that using oil of too high a
viscosity is more of a problem in OHC engines than in push-rod
engines because it starves the top end. In the former engines
the need for quick lubrication might be greater for the spinning
cam shafts.

But even all push-rod engines had camshafts with cam bearings that needed lubricating. If what you’re saying is true, then how does an OHC engine vs an push-rod engine change the lubrication requirements of the camshaft bearings?