Should I switch from 10w30 to 5w20? Switch to High Mileage Oil?

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Valvoline makes some thin 5W30's in full synthetic.
Mobile 1 makes some thick 0W and 5W20's in full synthetic.
 
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Well, your car has this thing called a "cooling system" that if properly maintained makes outside temps moot in most circumstances...
Not 100%. Try feeling around in an engine bay in the winter vs summer, or try doing an oil change (or better yet touch the oil pan or dipstick) at "normal operating temperature" in the winter vs summer. The entire engine bay and definitely the oil will be much hotter. In the summer my dipstick is so hot right after shutting the engine down I will burn myself if I touch the portion submerged in oil, not so in the winter.

Almost the entire bottom end of the engine (journals and bearings) are cooled exclusively by oil. A great deal of convective cooling happens from cold air running over the oil pan in the winter.

Water temperature only tells you the cooling system has not exceeded it's capacity to remove heat.
 
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Not 100%. Try feeling around in an engine bay in the winter vs summer, or try doing an oil change (or better yet touch the oil pan or dipstick) at "normal operating temperature" in the winter vs summer. The entire engine bay and definitely the oil will be much hotter. In the summer my dipstick is so hot right after shutting the engine down I will burn myself if I touch the portion submerged in oil, not so in the winter.

Almost the entire bottom end of the engine (journals and bearings) are cooled exclusively by oil. A great deal of convective cooling happens from cold air running over the oil pan in the winter.

Water temperature only tells you the cooling system has not exceeded it's capacity to remove heat.
^^
Exactly.
There is no correlation of engine coolant temperature to oil temperature. They are two completely different subjects with two completely different ways of dealing with heat, of which many engines have none for oil.

When people discuss oil and heat they are off the mark when they bring up coolant temperature, its completely invalid and the only valid discussion is if the oil temperature is available.

There are two things certain with oil temperatures being higher regardless of if one is able to measure the oil temperature.
1. If you are in a hot climate, your oil is running at a higher temperature (again, no matter what the coolant temperature says)
2. If you are running at high speeds, high loads or demanding conditions the oil temperature is higher. (many engines spray oil on the bottom on the pistons to cool the pistons at high speeds)

These two points above justify running one grade more heavy oil if it pertains to you. The USA is a HUGE country, what is the perfect oil viscosity for the north, is not perfect for the hot south, however now a days manufacturers mostly round it out and of course lean towards the most fuel efficient, not for the owner but for the manufacturers average MPGs.
Will it make a difference in engine wear? I would say with todays modern oils, most likely not by much if it is the manufacturer recommended grade, if any, then again, why is anyone here in BITOG then?

I run one grade (viscosity) higher where I live now in the south where summer time normal daily highs are in the 90s and winter time rarely every as cold as my old hometown on Long Island, NY and even more extreme cold upstate NY.
 
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4WD

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^^
Exactly.
There is no correlation of engine coolant temperature to oil temperature. They are two completely different subjects with two completely different ways of dealing with heat, of which many engines have none for oil.

When people discuss oil and heat they are off the mark when they bring up coolant temperature, its completely invalid and the only valid discussion is if the oil temperature is available.

There are two things certain with oil temperatures being higher regardless of if one is able to measure the oil temperature.
1. If you are in a hot climate, you oil is running at a higher temperature (again, no matter what the coolant temperature says)
2. If you are running at high speeds or demanding conditions the oil temperature is too. (many engines spray oil on the bottom on the pistons to cool the pistons at high speeds)
Yep … I have been watching mine this summer and they always come up and stay in this order
Oil temp +/- 222F
Coolant temp +/- 215F
Trans temp +/- 205F
 
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Yep … I have been watching mine this summer and they always come up and stay in this order
Oil temp +/- 222F
Coolant temp +/- 215F
Trans temp +/- 205F
Too bad this thread will be old by a cold winter, would be great to see the numbers again. Cool to have that information, I assume they are probes into the fluids?
 

OVERKILL

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Too bad this thread will be old by a cold winter, would be great to see the numbers again. Cool to have that information, I assume they are probes into the fluids?
With a coolant/oil heat exchanger, my oil temps track very much with coolant temps. Would be interesting how that looks on a RAM that doesn't have that during the winter up here.

UNADJUSTEDNONRAW_thumb_5a6.jpg
 

4WD

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Too bad this thread will be old by a cold winter, would be great to see the numbers again. Cool to have that information, I assume they are probes into the fluids?
Yes … and digital by selecting each … the only time I saw coolant approach oil temp was in the soft stuff in 4WD and then the electric fans took some of that back off …
Now as Dr Haas has pointed out (when starting out) the oil temp can take 20 minutes to catch up to coolant temps
Trans temp even slower …
 
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Yeah, without question, engines with oil coolers I would agree
With a coolant/oil heat exchanger, my oil temps track very much with coolant temps. Would be interesting how that looks on a RAM that doesn't have that during the winter up here.

View attachment 66073
I agree with an oil cooler but I dont think many OEM engines have oil coolers? At least in decades I never had a vehicle with one.
Exceptions might be specialized with tow packages.
 

OVERKILL

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Yeah, without question, engines with oil coolers I would agree

I agree with an oil cooler but I dont think many OEM engines have oil coolers? At least in decades I never had a vehicle with one.
Exceptions might be specialized with tow packages.

Surprisingly, our last several vehicles have had oil coolers, though the coolant/oil heat exchangers are the best as they heat the oil as well as keep it cool.

The BMW with the huge thermostatic controlled cooler in the valley was probably the worst, that huge aluminum engine shed heat like crazy in the winter and the 7L of oil didn't help matters. It was impossible to get the oil up to temp in the winter months, quite unlike the Jeeps and trucks.

The push to thinner oils and improved fuel economy has increased the presence of coolant/oil heat exchangers as it aides in expediting the warm-up process. It also works to regulate minimum viscosity by keeping the oil temperature in check, which is also important in the presence of thinner and thinner oils with reduced HTHS.
 

4WD

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Surprisingly, our last several vehicles have had oil coolers, though the coolant/oil heat exchangers are the best as they heat the oil as well as keep it cool.

The BMW with the huge thermostatic controlled cooler in the valley was probably the worst, that huge aluminum engine shed heat like crazy in the winter and the 7L of oil didn't help matters. It was impossible to get the oil up to temp in the winter months, quite unlike the Jeeps and trucks.

The push to thinner oils and improved fuel economy has increased the presence of coolant/oil heat exchangers as it aides in expediting the warm-up process. It also works to regulate minimum viscosity by keeping the oil temperature in check, which is also important in the presence of thinner and thinner oils with reduced HTHS.
No doubt my Pentastar warms up faster than the GM V8 … think the thermostat is “wired“ that way … but it also has a smaller cooler as you would expect - the GM has the upper level trailer package and lots of overall cooling …
 

4WD

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Yeah, without question, engines with oil coolers I would agree

I agree with an oil cooler but I dont think many OEM engines have oil coolers? At least in decades I never had a vehicle with one.
Exceptions might be specialized with tow packages.
Sometimes the addition of piston jets and oil coolers are associated with GDI or TDI … new hot spots …
That temp control is also a help with emissions etc … (keep it hot, but not too hot) …
 

shiny

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FWIW, this police interceptor is equipped with an oil cooler, engine cooler, transmission cooler, and even a power steering cooler. While certainly better than nothing, I don't know how much they help when the air flowing in through the front grill is coming off of pavement that's over 170 degrees.

Some people say to go with a grade thicker to handle the extra heat.

Other people say that a thinner oil flows faster and therefor cools better than a thicker oil, but doesn't protect metal parts as well as a thicker oil.
 
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FWIW, this police interceptor is equipped with an oil cooler, engine cooler, transmission cooler, and even a power steering cooler. While certainly better than nothing, I don't know how much they help when the air flowing in through the front grill is coming off of pavement that's over 170 degrees.

Some people say to go with a grade thicker to handle the extra heat.

Other people say that a thinner oil flows faster and therefor cools better than a thicker oil, but doesn't protect metal parts as well as a thicker oil.
Oil flows at exactly the same volume per RPM regardless of thickness with a positive displacement pump (so long as the oil is pumpable). Thicker oil can waste energy as heat from internal friction between the oil molecules, but not enough to make a major difference in oil temperature.

With all those coolers your oil should be mostly immune from outside temperature influence, but I still say: Thicker if maximum protection and longevity is the goal, thinner if you're trying to get maximum fuel economy.

Being that you live in the desert, you could easily get away with 20w50 year round, doesn't mean it's necessarily better than something like 10w40. Past a certain point you're just wasting energy from drag, however, thicker offers a larger margin of protection during extreme scenarios such as high RPM, high load (hills etc), and high temperatures (even if transient thanks to the oil cooler). If you drive like a maniac and frequently push the tachometer into the red zone, a higher viscosity will offer better protection. It's also much better for things like chain and cam wear.
 
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Even newer water cooled motorcycles (like my 2016 XSR900) have a water-to-oil cooler. My old 2005 Tacoma 4.0L V6 also has one. They've been around a long time.
 

shiny

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Oil flows at exactly the same volume per RPM regardless of thickness with a positive displacement pump (so long as the oil is pumpable). Thicker oil can waste energy as heat from internal friction between the oil molecules, but not enough to make a major difference in oil temperature.

With all those coolers your oil should be mostly immune from outside temperature influence, but I still say: Thicker if maximum protection and longevity is the goal, thinner if you're trying to get maximum fuel economy.

Being that you live in the desert, you could easily get away with 20w50 year round, doesn't mean it's necessarily better than something like 10w40. Past a certain point you're just wasting energy from drag, however, thicker offers a larger margin of protection during extreme scenarios such as high RPM, high load (hills etc), and high temperatures (even if transient thanks to the oil cooler). If you drive like a maniac and frequently push the tachometer into the red zone, a higher viscosity will offer better protection. It's also much better for things like chain and cam wear.
Thank you for explaining it this way. I read somewhere that the Ford engineers said Xw40 or Xw50 weight is too heavy for the lifters on this engine but 10w30 is fine. I don't drive like a maniac. The way I drive, the RPM rarely goes above 1500. Sometimes when there's no traffic at night I floor it for a few seconds just to clean out crud. (That always gets my heart racing!)

I'm going to stay with the 10w30. Like others have said, it's done a great job so far, and I'd like to put off a timing chain replacement as long as possible.

Thank you, everyone!
 
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