Difference between a tranny cooler and engine oil cooler?

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While we are on the subject of cold weather, one other "cooler" item comes to mind for the OP.

I have heard that heavy duty aftermarket transmission coolers sometimes work so well, that in severe cold weather the transmission does not reach proper operating temperature. The result is somewhat akin to the overly thick damaged oil that forms from overheating, in that the transmission may not shift properly. The fix was to bypass the cooler in cold weather, and some brands may have built-in bypasses.

In the distant past I have had very cold starts where the OEM-cooled auto tranny had that buzzing for a while, indicative of a hydraulic pump with an air bubble in it. The last ten years we used a manual transmission, or Prius, neither of which have that cold-related noise problem.

Wes
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In winter here, I used 0w40 synthetic in combo with an oil pan heater and the block heater and two battery blankets. Brrr.

Great post Ben!! Really good post.

And great vid's IB. I'm just glad I don't live in a freezer like some do. Cold here is 20F and really, really cold is 10F. Rotella 15/40 dino works just fine here for me.

ib516 wrote:

Wes Tausend wrote:
Do you think synthetic and ordinary modern oil will perform substancially different in cold weather? The article did say synthetic flowed easier, I believe. Do you think the difference is enough to justify the extra cost?

Wes
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Yes I do.

Cold pour test

Video #2

Video #3

Video #4

Ok, you got me, I see your point. The -40F/-40C was pretty dramatic. I've poured ordinary oil at about -10F and it is pretty syrupy, but reasonably liquid yet. The surprise I didn't expect was the near solid paraffin. If it can plug fuel, it can plug sumps. :E

I had to unexpectedly use my diesel last winter, but it was only about 0F out. I wonder how well the Rotella 15W40 flowed? I already had plans for a pan and tank heater and this cinches it.

Thanks for the links.

BenK wrote:
CR is a joke for me, but the Bible for most out there...

Ben,

I can't say Consumer Reports is a joke for me but I do take it with a grain of salt, especially regarding new vehicle tests, as you do.

I think the taxi test was legit, one of their better ones the way they honestly qualified it with some limitations. I will say I usually look at CR in the library, when I do, since a subscription wouldn't pay for me.

Wes
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CR is a joke for me, but the Bible for most out there...

Who drives and takes care of their vehicles like a NY Taxis company? Their bodies
usually wear out before their drive trains and mainly due to far fewer cold starts.
Plus their maintenance schedule and that could be El Cheapo Jug engine oil and filters

Used to use Mobil 1 synthetic in all of my vehicles. Even the then wife's, but
after a year in there and it still looked like honey could not stand to not change
the oil. Yes, am anal about that kind of stuff. Now she is the 'Ex', my mechanic
says both of the lux sedans showing poor maintenance. He has told her to take
them else where. Says she doesn't change it on a regular schedule and takes them
to the corner quick lube...

Agree that if the ICE and Automatic isn't used at the max spec but maintained
on a good schedule...that just about anything with a certified label will do. Ditto
El Cheapo filters

But...if driven at the OEM's spec limits or over...then the higher spec synthetics
will do better. Ditto ambient conditions at the OEM's spec limits.

Another 'but' to this...even placing the specifications of both regular oil
and synthetic oil (both 'good' ones) will have many not understand what it says
As not many are tech savvy and is NOT a knock on them...just that they have
other strengths and interests

Back on CR...looked at the specifications of their new automotive test facility.
Including that marvelous track. I'd love to have access to them, but after being
a subscriber during my younger years...found that even with all of their PhD's...their
recommendations normally did not fit me. Disliked most of what they recommended
bigger than a washing machine. Worst were automotive

Then the Matador recommendation. Or the SUV tip over and that roof mounted steel
out rigger...any SUV would tip over...even a lower CG sedan with a few hundred
pounds of steel on their roof

Another point is 'context' of it all. Royal Purple is a good synthetic for track
but poor for street. Little to no additive package for street usage. Mainly the
over nite shut downs and the cold morning starts



Back to the OP's questions.

IF you have the OEM tow package, employ the severe duty maintenance schedule,
keep within the OEM's specifications and drive 'normally' (not boy racer)

On that, you need to understand how the ratings system works...too many take
any 'one' ratings out of context and in absolute terms

Meaning that the MTWR (Max Tow Weight Rating) only applies if you have the 'curb'
vehicle. A 'curb' vehicle is the stripper model with the tow option. A manual
tranny and no options (other than that tow option) and one 150 lb driver

Take my Suburban. It's 'curb' is listed at 5,250 lbs. I've weighed it with me
(180), toolbox (+200), misc (+50). IIRC around 7,200 lbs. I'd have to unbolt
or cut out all of the options and take 30 lbs off my body to get it down to
the OEM listed 'curb'

Options: 4x4 (a few hundred lbs), automatic (a few hundred), big block (a few
hundred), highest option package (a few hundred), etc.

Note that in todays offerings...most OEMs do NOT offer for sale that 'curb' or
stripper model. They just used a test mule optioned out as a 'stripper'

If you driver HARD, tow HEAVY and travel in the high mountains...then be sure
to use the higher spec lube fluids, best filters and aggressive maintenance schedule

Wes Tausend wrote:
Do you think synthetic and ordinary modern oil will perform substancially different in cold weather? The article did say synthetic flowed easier, I believe. Do you think the difference is enough to justify the extra cost?

Wes
...

Yes I do.

Cold pour test

Video #2

Video #3

Video #4

ib516 wrote:
1) that CR test is almost 20 years old.
2) they tested synthetic oil in an taxi cabs that hardly ever shut off and are run continuously in mild weather (not 100*F above or 40* below).

Of course it will perform about the same as regular oil.

Try repeating that test at -40* with several cold starts and see what happens.

That test was useless at determining if synthetic is any better in any vehicle but a NYC taxi - in which it wasn't, and I'd agree.

From the article:
"Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service - stop-and-go city driving."

I'll stand by my suggestion that if you want extra insurance against heat related break down while towing, use a quality synthetic oil.

Well, I don't see where we are disagreeing here ib516, but thanks for replying.

My last statement was:

Wes wrote:
"Lastly, an engine that is never working at extreme heat levels won't benefit from more expensive synthetic. Consumer reports did an interesting study on this."

In other words I'm saying synthetic doesn't normally pay off in the family grocery getter. Unless one races to the store. But, I whole-heartedly agree with your statement,

ib516 wrote:
"I'll stand by my suggestion that if you want extra insurance against heat related break down while towing, use a quality synthetic oil."

You also said earlier,

ib516 wrote:
"Of course it will perform about the same as regular oil.

Try repeating that test at -40* with several cold starts and see what happens."

Do you think synthetic and ordinary modern oil will perform substancially different in cold weather? The article did say synthetic flowed easier, I believe. Do you think the difference is enough to justify the extra cost?

Personally, I thought the old article was well written and the logic is still as true today as it was then, but I can see that it might generate some controversy amongst some consumers. :)

There is another perhaps "controversial" article on the "classic" site that also seems to make a lot of sense (and humor) on additives. It's written for oil additives, but I think the common sense could be applied just as well to fuel additives, then and today.
Link: Is That Additive Really A Negative?
Food for thought.

Wes
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1) that CR test is almost 20 years old.
2) they tested synthetic oil in an taxi cabs that hardly ever shut off and are run continuously in mild weather (not 100*F above or 40* below).

Of course it will perform about the same as regular oil.

Try repeating that test at -40* with several cold starts and see what happens.

That test was useless at determining if synthetic is any better in any vehicle but a NYC taxi - in which it wasn't, and I'd agree.

From the article:
"Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service - stop-and-go city driving."

I'll stand by my suggestion that if you want extra insurance against heat related break down while towing, use a quality synthetic oil.

...

sheripoms,

The tranny cooler and engine oil cooler are similar items and could probably be interchanged in function. Both remove heat from oil. If your Tahoe will be working hard, it will benefit from upgrading both coolers.

Regular petroleum oil begans to break down around 275 degrees Fahrenheit. The oil becomes thicker and therefore less flows at the pre-set oil pressure, robbing bearings of needed cooling. In the case of auto trannies, the control valving will not work right, possibly leading to slow slipping shifts and other problems. Synthetic oils resist heat up to around 500 degrees F and are less susceptable to lube failure. Synthetic oil was developed for high heat aircraft turbine engines.

Heavier piston engine loads cause more bearing heat and require more cooling flow to remove said heat, so too thick of oil will fail in this regard. One thing to keep in mind is that some molecules are subjected to extreme heat even when the average temp is within reason. So oil continuously breaks down over time and should be changed at suggested OEM service intervals. Heavy towing requires more frequent intervals for this reason. In this way, oil does wear out.

Some years ago ('90's?), GM quit installing oil coolers in their Corvette and sent them out of the factory with Mobil 1 synthetic already installed. Most owners kept this up since the book called for it. The idea was that synthetic protected the cars during high speed road racing just as well as the former oil coolers. If it is good for a hard working Corvette, it is good for a hard working Tahoe.

Do not be afraid of synthetic weight grades. In simple terms, an oil designated as 15w40 (for example) means that the oil will not get thicker than 15 weight when cold, nor thinner than 40 weight when hot. Synthetic is simply more stable than a straight weight oil. Straight weight oils vary widely in viscosity (thinness) and are seldom used anymore. Install the seasonal oil weight that the owners manual calls for, be it synthetic or ordinary refined petroleum oil. By the way, the "w" in 15w40, or 5w20, stands for winter, the first use of such oils until it was realised that it worked better for cold starts all year.

I own a Ford V-10 that has come with a built-in oil cooler since about 1997. The engine was designed for hard work and auto trannies packaged with it all have factory tranny coolers also. Ford initially called for 5w30 oil (all season moderate climates) and then changed that to 5w20 when it became apparent that oil was not circulating fast enough, especially to the overhead cams.

Lastly, an engine that is never working at extreme heat levels won't benefit from more expensive synthetic. Consumer reports did an interesting study on this.

Wes
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Turtle n Peeps wrote:

Redsky wrote:
Synthetics can be worse for engines operating under high temperatures. almost all of them are 5W40 formulations and the engine manufacturers specify this weight for sub zero driving conditions and air temperatures under 90F degrees. In hotter weather they specify a 15W40 motor oil regardless of whether it is a mineral/dino or synthetic motor oil. You do not want to be starting the engine with a 5W oil on a 100 degree day and waiting for it reach 15W to be properly lubricating the engine bearings.

You do not have any understanding on how a multi grade oil works.

X2, not a clue.