Well I thought you were talking about winter. That's not a winter!
I would agree 50F to 90F does not require a viscosity change.
I would agree 50F to 90F does not require a viscosity change.
5W20 and summer heat
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"Well I thought you were talking about winter. That's not a winter! I would agree 50F to 90F does not require a viscosity change."
Huh? The original post was about FND's upcoming summer road trip, as were my posts. Specifically whether he needed something thicker than 20w than his factory-specified, year-round 5w-20 oil he's currenty using. Back in the 50's, 60's, and 70's, it was common for engines to run hot and sometimes overheat on summer road trips. The newer cars I've owned don't even seem familiar with the term "overheat," except for occasional track events in Summer. My point simply being that this downgrades the need/significance of switching to thicker weights during the hot months. My suggestion to FND was that, if his Windstar cooling system was as efficient as my cars, he probably didn't "need" a thicker oil for his trip, something that Ford apparently agrees with.
Huh? The original post was about FND's upcoming summer road trip, as were my posts. Specifically whether he needed something thicker than 20w than his factory-specified, year-round 5w-20 oil he's currenty using. Back in the 50's, 60's, and 70's, it was common for engines to run hot and sometimes overheat on summer road trips. The newer cars I've owned don't even seem familiar with the term "overheat," except for occasional track events in Summer. My point simply being that this downgrades the need/significance of switching to thicker weights during the hot months. My suggestion to FND was that, if his Windstar cooling system was as efficient as my cars, he probably didn't "need" a thicker oil for his trip, something that Ford apparently agrees with.
Well you were saying that OT is not independant of coolant temp. When in fact it is.
Again I would agree that modern cars do not have problems with summer heat, nor overheat unless something is wrong with them.
Again I would agree that modern cars do not have problems with summer heat, nor overheat unless something is wrong with them.
I did a search on both this site and several authoritative auto websites, and the concensus appears to be (some seemingly obvious info here):
1. There's normally a direct correlation between the oil and coolant temps; if one rises or drops in steady-state operation, the other typically will as well, and in the same rough proportion.
2.In a transitory situation, such as when changing from flat highway to a long, steep grade, oil and coolant temp may temporarily rise or fall at different rates.
3. Oil temp is typically about 20-40F higher than coolant temp.
I can see how my earlier comment wasn't worded very well -- I was simply trying to say that, in steady-state operation, changes in oil temp will roughly track changes in the coolant temp gauge. If certain temp gauges are sloppily calibrated, that's another topic...
[ May 19, 2004, 06:03 PM: Message edited by: TC ]
1. There's normally a direct correlation between the oil and coolant temps; if one rises or drops in steady-state operation, the other typically will as well, and in the same rough proportion.
2.In a transitory situation, such as when changing from flat highway to a long, steep grade, oil and coolant temp may temporarily rise or fall at different rates.
3. Oil temp is typically about 20-40F higher than coolant temp.
I can see how my earlier comment wasn't worded very well -- I was simply trying to say that, in steady-state operation, changes in oil temp will roughly track changes in the coolant temp gauge. If certain temp gauges are sloppily calibrated, that's another topic...
[ May 19, 2004, 06:03 PM: Message edited by: TC ]
I rest my case.
Assuming properly functioning cooling and lube systems, and assuming a properly functioning and reasonably accurate temp gauge, my comment is dead-on accurate. The oil temp will typically be 20-40F higher than coolant temp during steady state operation. If a coolant gauge indicates "normal," and the factory considers oil temps 20-40F higher than that "normal," why would the oil temp be something OTHER THAN THAT during steady state driving? As far as ambient outside temps are concerned, a gauge that reads 220F year-round is indicating an oil or fluid at 220F, regardless of whether it's January or July.
I rest my case...
I rest my case...
There's an old engineering saying that goes something like this, "follow what the evidence tells you, not what logic dictates".
I would say the oil temp and the water temp are related but do not run concurrent. Oil acts as a coolant as well.
The definitive test requires an oil temp gauge.
The definitive test requires an oil temp gauge.
Coolant systems do not limit peak temps. Quite often you get over heat situations in the desert towing or off roading. On many occasion Road and Track and Motor Trend have had at least one vechile in their truck testing fail to maintain a proper coolant temp and quite often 2-3 three other vechiles were at their limit trying to maintain a proper coolant and oil temp.
Very few coolant or oil temp gauges read real time any more. Most are heavily buffered or they only read in the normal range until they exceed the preset temp limit then they will rise into the read to let the driver know something is wrong. Most are actualy idiot lights with a needle!
Very few coolant or oil temp gauges read real time any more. Most are heavily buffered or they only read in the normal range until they exceed the preset temp limit then they will rise into the read to let the driver know something is wrong. Most are actualy idiot lights with a needle!
The thermostat regulates coolant temperature at one point in the engine. The coolant temperature gauge reads the temperature at one point in the engine (sometimes nearly the same point). Likewise with oil temperature gauges and thermostatically controlled oil coolers.
I always change my oil after driving my vehicle 12+ highway miles. In the winter, the oil draining out is warm. In the summer, the oil draining out is HOT. In both cases the coolant temperature gauge reading is the same. It’s the same when lifting the hood. In the summer, you get a blast of HOT air. In the winter, the air not nearly as hot.
For me and my vehicles, there’s plenty of evidence that average oil temperatures are significantly higher in summer than winter, even during highway driving. Whether the difference is enough to need a different viscosity of oil is another matter.
I always change my oil after driving my vehicle 12+ highway miles. In the winter, the oil draining out is warm. In the summer, the oil draining out is HOT. In both cases the coolant temperature gauge reading is the same. It’s the same when lifting the hood. In the summer, you get a blast of HOT air. In the winter, the air not nearly as hot.
For me and my vehicles, there’s plenty of evidence that average oil temperatures are significantly higher in summer than winter, even during highway driving. Whether the difference is enough to need a different viscosity of oil is another matter.
And we have reached a conclusion that a thicker viscosity would make any difference?
All I know is my 97 F150 with the 4.6 had 163,000 miles on it when I sold it with not one engine repair.
My '99 is on the same track. 102,530 miles on the odometer tonight.
I stand by my statement that a 5w20 used in an application where specified is fine.
I was happier with my '97. It was a 2wd with a 3:08 rear end and small tires. (Supercab Flareside) I averaged 17.1 mpg over 163,000 miles. 20 was easily obtainable on the freeway.
My current truck is a '99 F150 with 4x4 and 3.55 gears and taller tires. It downshifts more often and is getting about 15.5 mpg (102,000 miles).
If I had to do it again, a 2wd truck is fine with the 4.6 and will get better mileage than the 5.4. With the extra weight of the 4x4 and taller tires, I think I'd get nearly the same mileage with the 5.4.
But if I was really overly concerned about fuel mileage, I probably wouldn't be driving a full size truck! Not to say it doesn't matter, just a bit less of a factor.
So, fuel mileage is so-so, but in terms of reliabiltiy, I give the 4.6 a huge thumbs up!
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