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Discussion Starter #61
Anyone know what happens to the viscosity of the oil at 260+ degrees? According to the manufacturers 270+ degrees will not harm the oil itself, but does it put it outside of a good viscosity range for the engine?
Oil visc changes very little at high temps. I'll go find a chart.

Here we are. As you can see, the big visc changes are at cold temps. When hot, oil visc changes flatten out.

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Wouldn't under load oil temps skyrocketing suggest the oil does infact remove heat from the engine? I agree the stock "heat exchanger" since that is what we have to call it is insufficient in size or temp difference to adequately cool the oil.
 

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Discussion Starter #64
Wouldn't under load oil temps skyrocketing suggest the oil does infact remove heat from the engine? I agree the stock "heat exchanger" since that is what we have to call it is insufficient in size or temp difference to adequately cool the oil.
There is a difference between removing heat from the engine and removing significant heat from the engine. The coolant removes huge heat from the engine, ballpark 10k btu, engine and turbo combined, and then dumps to air traveling thru the radiator.

The oiling system in contrast, pulls a much smaller amount of heat from the engine, but then has no place to dump it. What heat energy the oil loses is mostly thru the AL pan. It also is able to dump a little bit of heat to the coolant via the oil/water heat exchanger, but the latter is hamstrung by the small temp delta.

The oiling system getting pretty hot is less about how much heat energy it pulls from the engine and more about there being no place for it to adequately get rid of heat energy. That's why those that installed an oil cooler saw such a drop in oil temps--finally the oil had a way to dump heat.
 

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How much heat would the coolant remove if the radiator received no cooling air flow? Similar to how the oil "heat exchanger" receives no/far insufficient cooling flow.
 

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Oil temps seem to go from 200-208 +/- degrees under moderate load to somewhat easily sustained at 240 and well beyond quickly under heavy loads.
 

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Discussion Starter #67
How much heat would the coolant remove if the radiator received no cooling air flow? Similar to how the oil "heat exchanger" receives no/far insufficient cooling flow.
If the rad got no airflow, there'd be no heat xfer from the rad due to (highly effective) convection. Instead there'd only be heat xfer to stationary air via conduction and also some radiation--neither of which would dump much heat.

Re. similar. Well, they'd both suck, but for different reasons. The problem with the heat exchanger is that the other fluid, coolant, is almost as hot as the oil, and there isn't much surface area. Heat xfer is proportional to surface area and delta temp. In your "got no airflow" example, there is no flow, so no heat xfer due to convention. So no airflow to rad means not much heat xfer.
 

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Discussion Starter #68 (Edited)
Someone mentioned removing the vent assembly in front of the engine to increase air flow to the radiator, not to mention tranny fluid cooler, AC condensor, and intercooler. That's not a crazy idea. I looked at that when I was doing the radiator swap. I noted, however, that the vent assembly also provides some of the airflow guidance from the grill into the radiator. The easy solution would be to hack out the movable events while leaving the bits that direct airflow--they are shrouding really. But I didn't want do do a hack job on it, so I left if alone.

Another thing I noticed is that there isn't any shrouding on the sides of the radiator, so lots of air is coming thru our grill but escaping out left and right, as opposed to going thru something useful and taking some heat with it. So when I get a chance I'm going to improve on the side shrouding a bit.
 

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Re. Doesn't explain the piston cooling nozzles the engineers designed to spray oil onto the bottom of the pistons. What's to explain? The design reduces peak piston temps. That's not the same as cooling the engine. The little cyclical oil spritz could be pulling 10btu from the pistons while the radiator pulls 10000btu from the engine and turbo. It's just a little once per rev spritz, how much heat energy do you really expect it to remove?
I'm now exhausted at this trivial bantering over a non-issue. You don't like your coolant temps. Very well. Good day.
 

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FWIW when the bearings in my crankshaft pulley froze snapping off the belt the ambient air temp was in the 40s (cold but don't remember exact F*) and of course running 80mph on I-26 Iad no idea it happened.

What I DO recall being alerted to engine temps high. The oil was 265ish, maybe 268 yet the coolant was in the 220s with no fan belt for how long??? Once pulled over and she cooled with the hood up I babied her another 5 miles to the CJDR dealer in Orangeburg, SC with oil temps never exceeding 230.

Coasted down hills in N and accelerated up watching oil temps. Of note the coolant never went above 220 whether running at 80 and oblivious to being belt-less, or driving easy w/o a belt. That was 23,000 miles ago. Were it a Summer night in SC doubt that would have been pulled off.

Coolant temps never were relevant.
 

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2 years ago pulling 8x24 cargo w/ 5 4-wheelers and 2 dirt bikes in 90* Florida heat at 65mph. Dry weight 7,000 and likely 7,500 fueled w/ gear. Where is the need for greater coolant capacity when oil temps are higher?
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Discussion Starter #74
FWIW when the bearings in my crankshaft pulley froze snapping off the belt the ambient air temp was in the 40s (cold but don't remember exact F*) and of course running 80mph on I-26 Iad no idea it happened.

What I DO recall being alerted to engine temps high. The oil was 265ish, maybe 268 yet the coolant was in the 220s with no fan belt for how long??? Once pulled over and she cooled with the hood up I babied her another 5 miles to the CJDR dealer in Orangeburg, SC with oil temps never exceeding 230.

Coasted down hills in N and accelerated up watching oil temps. Of note the coolant never went above 220 whether running at 80 and oblivious to being belt-less, or driving easy w/o a belt. That was 23,000 miles ago. Were it a Summer night in SC doubt that would have been pulled off.

Coolant temps never were relevant.
When your coolant system has a big failure, like the pump isn't turning, you can't rely on the coolant temp sensor. With no pump, you're now in some failure mode and it's hard to know what it will look like. About 10yrs ago a couple buddies and I were doing a 5hr race. A coolant hose developed a leak and the engine started loosing coolant. This was before I installed a coolant pressure sensor so the driver didn't know. His coolant temp never went up, but, after a couple laps, the oil temp was clearly higher than normal. This is my car mind you, my first race car, and I loved the thing.

The increased oil temp worried the driver so he came in. But by then, the engine was toast. Cracked head and failed rings. The coolant sensor never indicated a problem. Was a bummer because engine # 5 had been an early favorite. The point is that failure modes--what precisely happens when a complicated system fails, can be tricky. I don't know what happens at the EcoD coolant temp sensor if the pump quits turning on a hot engine, but I'd be slow to draw conclusions from the incident re. the importance of coolant.

Re. what is the need for greater coolant capacity when oil temps are higher. I assume that you mean heat xfer capacity. There is a reason why the max coolant temp (240?) is lower then your max oil temp (269?). I'd be happy to explain, but I think I've driven people crazy enough. If you really think 237deg oil is a bigger problem than 221deg water, then don't just assert it, explain your reasoning.
 

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No assertions simply real world experience on two different occasions. As others have stated and the picture demonstrates, pulling a near capacity load at a higher speed in 90*F Florida Summer heat and the coolant temps were well within spec therefore an increase in coolant capacity simply is not needed.

Weight outside of specs or 8% grades on a consistent basis may warrant a 2500 for safety and longevity vs. trying to adapt a 1500 for these circumstances.
 

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Discussion Starter #76
No assertions simply real world experience on two different occasions. As others have stated and the picture demonstrates, pulling a near capacity load at a higher speed in 90*F Florida Summer heat and the coolant temps were well within spec therefore an increase in coolant capacity simply is not needed.

Weight outside of specs or 8% grades on a consistent basis may warrant a 2500 for safety and longevity vs. trying to adapt a 1500 for these circumstances.
I would define the "coolant temp spec" as "thermostat management range." How would you define the coolant temp spec?

This was never about "coolant capacity." You sure that's the phrase you want to use?
 

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I would define the "coolant temp spec" as "thermostat management range." How would you define the coolant temp spec?

This was never about "coolant capacity." You sure that's the phrase you want to use?
A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A requirement specification is a documented requirement, or set of documented requirements, to be satisfied by a given material, design, product, service, etc. It is a common early part of engineering design and product development processes in many fields.

Is MS12106 a known Chrysler coolant Spec?
 

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Discussion Starter #78 (Edited)
A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A requirement specification is a documented requirement, or set of documented requirements, to be satisfied by a given material, design, product, service, etc. It is a common early part of engineering design and product development processes in many fields.

Is MS12106 a known Chrysler coolant Spec?
That was a very strange response. You going add something of value to the conversation, or just waste time googling a few generic definitions?

You used the phrase "coolant temps were well within spec." What do you perceive those coolant temp specs are? Of course, pls try to support your assertions.

Lets see if you can agree with this: The engine has a preferred range spec of operating temps. We know this because the engine has a thermostat and we can guess pretty closely what the preferred temp range is by watching the temp on the EVIC closely. The engine also has an identified "too hot" spec which was tentatively ID'd as 240deg. We know it's a "too hot" spec because of what apparently happens when the coolant hits that temp--derate.
 

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That was a very strange response. You going add something of value to the conversation, or just waste time googling a few generic definitions?

You used the phrase "coolant temps were well within spec." What do you perceive those coolant temp specs are? Of course, pls try to support your assertions.

Lets see if you can agree with this: The engine has a preferred range spec of operating temps. We know this because the engine has a thermostat and we can guess pretty closely what the preferred temp range is by watching the temp on the EVIC closely. The engine also has an identified "too hot" spec which was tentatively ID'd as 240deg. We know it's a "too hot" spec because of what apparently happens when the coolant hits that temp--derate.
If you go ask a dealer as an every day joe, i bet anything less than derate = "within spec" CaptainMal's transmission temps were lol.
 
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