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Oil viscosity and synthetic vs regular

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 PostPosted: Sun Jul 02, 2017 2:34 pm   
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Currently i have 10w40 oil in the engine.

I know you guys suggest using synthetics but i change oil every 3000 or 3 months whatever comes first, so synthetics is waste of money it only good of synthetics is that it keeps its characteristics for longer period of time/miles like 5000-7000 which i never push with the oil.

Viscosity is same of synthetic and not synthetic oil really its all about oil weight you chose.
All comparisons online are made at -40, -30 F which i don't care about really unless you can show me a normal comparison of synthetic and regular or blend oil at normal temperature, and it shows synthetic flows better

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In California temps never go below 45F so based on oil viscosity chart i don't need multi grade oil here all year long.

[ img ]

I wanted to go with multi grade oil perhaps 15w or 20w, unfortunately Valvoline and Mobil only sell 10w-30, 10w-40 next level up is 20w-50 i think 50 is overkill.

What i am trying to decide is viscosity at engine working temperature should i go with 30 or 40?

This i don't understand and i know you don't too. :D Perhaps we could find answer together.



Lets look at this chart many are similar they show oil grade e.g. 10w-30 go up to 70degree F max when 10w-40 goes to 90 degree F ambient temperature.
Why is that?
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 PostPosted: Sun Jul 02, 2017 5:15 pm   
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I will offer what little insight I can based on my '04 owner's manual. It states very specifically the 2 oil viscosities to use are:
10W-30 if the ambient air temps before the next oil change are anticipated to be from 0° F to over 100° F; or,
5W-30 (preferred) if ambient air temps before the next oil change are anticipated to be below 100°.

Those are the only 2 oil viscosities recommended by Chrysler for the Sebring convertible. Why use anything else?

As to your 2nd chart, it is Porsche specific so why concern yourself with anything it contains - unless, of course, you have a Porsche and you're concerned about what oil to use in it.

As a side note, with a 2001 2.7L I'm sure you know about these engines sludging up and imploding. Your habit of changing the oil every 3,000 miles is a good thing to do. However, I would suggest you might want to consider using synthetic for one reason. The purpose of synthetic is not to increase oil change intervals. Rather, synthetic oil adheres to the internal engine parts much longer than traditional oils. What that simply means is that if you make a lot of short distance drives (grocery store, shopping, short work commute, etc.) synthetics will reduce the number of "cold" starts your engine is subject to. The fewer cold starts, the less wear on the internals. Only you know your driving habits in this regard.


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 PostPosted: Sun Jul 02, 2017 7:57 pm   
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 PostPosted: Sun Jul 02, 2017 8:25 pm   
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My 2¢ --

Manufacturer’s oil viscosity recommendations are based on many factors, but one of the most critical is the clearance between moving parts.

You got your thick oil. You got your thin oil. And you got your CORRECT oil – based on viscosity for the climate, engine and operational situation.

I would suggest to always use the oil recommended by the engine manufacturer.
As hard as it is to believe, none of us knows more about engine oils than the people who designed and built the engine.

As much fun as it is playing “garage mechanical engineer” there could be consequences.

Today’s precise computer controlled machining allows for smaller, more precise spaces between parts. Thinner oils do a better job of flowing freely through the engine while still filling the tighter clearances.

Too thick oil will give you outstanding oil pressure.
However, the parts and clearances inside the engine could actually be starved for oil due to lowered flow rate/volume.

Thicker oil being harder to push through the many oil passages and spaces between parts,
makes the oil pump work harder, which in turn increases oil pump discharge pressure, but at the same time, decreases oil volume.

Another point to keep in mind – oil circulating through the engine accounts for a large percentage of engine cooling.
Reduced oil-flow reduces cooling causing lubricated moving parts to operate at higher temperatures. Higher parts temperatures result in more wear over time.


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 PostPosted: Mon Jul 03, 2017 7:54 am   
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10W-30 if you're in warm weather.

Quote:
Thicker oil being harder to push through the many oil passages and spaces between parts,
makes the oil pump work harder, which in turn increases oil pump discharge pressure, but at the same time, decreases oil volume.


Thicker oil also doesn't help fuel economy..

Quote:
Too thick oil will give you outstanding oil pressure.

Yeah, I see some folks try and use 10W-40 to solve the 'flickering oil pressure light at idle' issue, but it is just a band-aid solution. The thicker oil causes all of the aforementioned problems, and if the oil pressure sender is on its way out, the pressure light will be back on sooner than later (especially in warm weather).


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 PostPosted: Mon Jul 03, 2017 8:11 am   
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10W30 or 10W40 brand name oil change it often. Non synthetic.


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 PostPosted: Mon Jul 03, 2017 8:34 am   
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Bumping it up a notch won’t hurt anything.
However bumping it up on an engine designed for 5w-20 or 5w-30 to 20w-50 like the OP referenced,
is where the flow characteristics can have a bad effect over time.


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 PostPosted: Mon Jul 03, 2017 9:29 am   
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5W20 is usually called for as a fuel economy measure. The first change I did on my 06 I used Mobil 1 5W20 and sent a sample out of what I drained. It had 5W20 in it. Since my entire fleet now calls for that, I will run them all the same; Mobil 1 or Pennzoil Platinum depending on price.
Oh and send every change out to be analysed. If I can push the intervals out I will.


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 PostPosted: Mon Jul 03, 2017 4:27 pm   
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I once ran into a retired Chevy motor engineer. We got to talking about oil. These are his words not mine. The only reason they went to 5w was to get a little better gas mileage so they could get a rebate from the government. NOT to make your engine last longer. He also said HE would never use it in his own car. Like I said HIS WORDS.


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 PostPosted: Mon Jul 03, 2017 8:36 pm   
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Terry, that's interesting. Did he say, or otherwise indicate, what he used. I'm assuming likely 10W-30 which is what I had always used right up until I got my '04 GTC in 2005 and read the 5W-30 recommendation.


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 PostPosted: Mon Jul 03, 2017 9:42 pm   
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No Don he just said he would never use 5W. I'm sure 10W was what he was using. When he said 5W gives better gas mileage he said is was very very small but you add that up on a million cars and the Government gives you a rebate.


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 PostPosted: Mon Jul 03, 2017 11:43 pm   
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While the Chevy motor guy says the only reason for 5w oil is MPG savings, from articles I’ve read, written by professional engine builders, there are other reasons not simply MPG.
For me, that’s too simplistic an answer, for a complicated, closely toleranced piece of machinery.
One example - Too thick an oil on a Ford 4.6 has been known to cause slow timing chain tensioner reaction on cold start up, causing the longer than normal timing chain to jump time. Even going from 5w-20 or 5w-30 to 10w-30 is not recommended.
There is another foreign brand (I forget which Audi – MB ??) that has the same type problem.


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 PostPosted: Tue Jul 04, 2017 8:52 am   
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EJS wrote:
While the Chevy motor guy says the only reason for 5w oil is MPG savings, from articles I’ve read, written by professional engine builders, there are other reasons not simply MPG.
For me, that’s too simplistic an answer, for a complicated, closely toleranced piece of machinery.
One example - Too thick an oil on a Ford 4.6 has been known to cause slow timing chain tensioner reaction on cold start up, causing the longer than normal timing chain to jump time. Even going from 5w-20 or 5w-30 to 10w-30 is not recommended.
There is another foreign brand (I forget which Audi – MB ??) that has the same type problem
.


Ed I don't doubt this in the least. These motor all have been designed way after my conversation with that engineer. But I don't think our 2.7 or 2.5 or even the 3.5 come into the same class as the two motor you mentioned.


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 PostPosted: Tue Jul 04, 2017 10:52 am   
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EJS wrote:
For me, that’s too simplistic an answer, for a complicated, closely toleranced piece of machinery.


Yeah, I'm not buying it either. If the folks who designed my engine tell me I should use 5W in colder temps, that's what I'm using. If Chevy designed an engine(s) to use 10W and just changed their recommendation without investigating possible consequences to get government dollars, then that's bad engineering (and/or corporate corruption). There's no reason to assume 5W-30 is a government conspiracy based off one old anecdote from a retired Chevy engineer.


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 PostPosted: Tue Jul 04, 2017 12:26 pm   
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The 4.6L Ford is about 5 years older than the 2.7L, but has tighter bearing tolerances.
To me this shows that Ford designed this tight tolerance engine, not just for the fuel savings alone, but also to address other design issues.
Using the light weight oil allowed them to not only achieve greater fuel economy, but also to develop
more horsepower, while eliminating the timing chain/tensioner issue.
What this shows me is that using a heavier oil because one doesn’t like light weight oil maybe be OK in many cases, but can, in certain cases, have very costly consequences.

I gulped hard when I saw Lincoln call out 5w-20.
But after a few discussions with a few experienced Ford people, they made it perfectly clear.
A 4.6L will routinely go over 300,000 miles on the factory spec’ed 5w-20 oil.

Times sure have changed from the days of my 327 Chevy, with clearances big enough to stick your finger through, and required 40 weight oil to fill the gaps.


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