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Discussion Starter · #1 ·
Re: 3.6L Engine.

2012 Owners Manual:
SAE 5W-30 engine oil is recommended for all operating
temperatures.
Under no circumstances should oil change
intervals exceed 8,000 miles (13 000 km) or six months,
whichever occurs first.

2013 Owners Manual:
SAE 5W-20 engine oil is recommended for all operating
temperatures.
NOTE:Under no circumstances should oil change intervals
exceed 10,000 miles (16,000 km) or twelve months,
whichever occurs first.

Why the difference?
 

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Usually manuals have different recommendaations for different climates. Being in a warm climate, I generally use 10W-30 for everything.

The oil pumpis another place where an electric pump and accumulator could be used but is different from steering and brakes in that the pressure requirement varies with engine speed so an engine driven pump makes sense. Simiilarly time has shown that a georotor pump is better for automotive applications than a gear pump.

Ideally, oil would be of a constant viscosity regardless of temperature (dino oil varies A Lot, synthetic is much better. If I lived in a cold climate, I'd run synthetic. Since I do not, there are more options.

What an oil spec says (say a 5W-30) is that when cold it get no thicker than a 5 weight and when hot it gets no thinner than 30 weight (5 cold is thicker than 30 hot). This is done by blending oil and additives, mostly long chain polymers.

When the additives break down through age and temperature, they become less conforming and eventually a 5w-30 will act like a straight weight 20. This is why oil needs to be changed periodically and not just filtered (are other reasons such as contaminants due to crankcase ventillation but age is the main one).

ATF is different (starts out like a 15 or 20 weight & makes a good hand cleaner) and lasts much longer since it is not supporting combustion pressures.

The two stage oil pressure relief in the Pentastar is odd but maintains the 10 psi/1000 rpm that has been a useful guideline for many years.
 

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Discussion Starter · #3 ·
Usually manuals have different recommendaations for different climates. Being in a warm climate, I generally use 10W-30 for everything.

The oil pumpis another place where an electric pump and accumulator could be used but is different from steering and brakes in that the pressure requirement varies with engine speed so an engine driven pump makes sense. Simiilarly time has shown that a georotor pump is better for automotive applications than a gear pump.

Ideally, oil would be of a constant viscosity regardless of temperature (dino oil varies A Lot, synthetic is much better. If I lived in a cold climate, I'd run synthetic. Since I do not, there are more options.

What an oil spec says (say a 5W-30) is that when cold it get no thicker than a 5 weight and when hot it gets no thinner than 30 weight (5 cold is thicker than 30 hot). This is done by blending oil and additives, mostly long chain polymers.

When the additives break down through age and temperature, they become less conforming and eventually a 5w-30 will act like a straight weight 20. This is why oil needs to be changed periodically and not just filtered (are other reasons such as contaminants due to crankcase ventillation but age is the main one).

ATF is different (starts out like a 15 or 20 weight & makes a good hand cleaner) and lasts much longer since it is not supporting combustion pressures.

The two stage oil pressure relief in the Pentastar is odd but maintains the 10 psi/1000 rpm that has been a useful guideline for many years.
Okay, so what's this have to do with my question? :confused:
 

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Read and follow your manual -- not any other. The change has nothing to due with climate or temp. "Recommended for all operating temperatures" means you use the posted weight whether you live in FL or ND. Chrysler must have re-certified 5w20 in '13 and later. They probably figured out they could increase mpg by .1%, and it caused no harm. I use 5w30 -- which is what my manual says. Once broke in, I follow my manual for change intervals as well.
 

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Okay, so what's this have to do with my question? :confused:
The man provides us with many facts. It makes him feel good.

So what if it doesn't answer your question. :lol:


---
 

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Discussion Starter · #8 ·
Official response from Jeep Customer Assistance Center:

According to available information, the engine oil viscosity change was
made to improve engine efficiency/fuel economy and with that the
engineers determined that the change interval could be extended.

As previously stated, we suggest to follow the recommendations and
information found in the Owner's Manual for your specific vehicle.
 
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