Quote:
Originally Posted by quarterliter
Oil is rated hot at 212F and running it cooler than that is not good. Hotter is better than too cool. SRT will state that 300F oil temps are nothing to worry about with penziol ultra, a high quality GRP III oil. Unless you are seeing 300+ oil temps, an oil cooler is not necessary. An oil cooler will reduce flow in an engine as well. More distance the oil has to travel which equates to more fluid drag. Also with oil that cool, contaminants such as gasoline, and water will not evaporate off as effectively.
Moral of the story is you should use a good oil such as 5w40 rotella t6 and change it every 3000 or so.
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Quote:
Originally Posted by jkv45
All oil, synthetic or convention, is designed to run at 212F - that's the temp they use to get the higher rating. There may be instances where an engine could exceed that, but with a water-cooled engine it wouldn't be by much in most conditions.
With oil, thicker and colder are NOT better. An oil cooler will extend warm-up time also, which is also not an advantage.
If you are concerned about maximum protection, move up to an ester-based synthetic oil (Group V) like Redline or Motul which can withstand extreme heat and pressure that even a Group III synthetic like Rotella T6 can't. But if you are getting into that range, you most likely have bigger problems.
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The Thermo-Bob guy agrees with these statements too.
http://www.watt-man.com/uploads/TB_FAQ.pdf
Quote:
"Why a 195°F thermostat instead of a 160°?"
Because hotter is better until it causes items to decrease in life. The KLR oil is notoriously cold in the winter, hotter only helps get more heat into the oil which helps get rid of contaminants that enter the oil. I’ve dealt with a few engine designers over the years and they’ve said if mileage and engine life was their primary design goal, they’d probably use a 220° or 230°F thermostat. Current materials / design seem to be around 195°-210°F on the exit side of the engine, and for the cars that actually have the thermostat on the inlet side of the engine controlling the inlet temperature, they control at 180°-195°F, which results in very similar exit temps for both designs.
"I thought hotter was worse"
I hear this occasionally from the over-generalizers. They get on a "hotter is worse" thread because we all know that 300°F is worse than 250°F. And based on experience, 250° is worse than 230°. But is 160° worse than 140°? No, it's better. Engines are designed to run in a certain operating range... 140° stinks, 150° is better, 160° is better still, etc. You want to be in that 190°-220° range all year to keep clearances right and to keep your oil free of water.
Bottom Line – This hasn’t raised peak temps at all – but have raised minimum temps when you're riding and it's below 80°F outside. Even here in the desert, that's the majority of my year. In a lot of places, that's the entire year.
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I personally think it's more advantageous to upgrade the cooling system with something like a Thermo-Bob to add a bypass loop. That way, the coolant is constantly circulating through the engine staying a consistent temperature. When it gets too hot, the thermostat opens and allows coolant through the radiator to dump some heat. When it cools down again, it returns to just flowing through the engine.
By comparison, the stock setup is a single loop. When the thermostat is closed, it essentially blocks flow of all the coolant. That makes it harder for the heat of the engine to get to the thermostat to cause it to open when the engine gets warm. When it does open, the cold coolant that's been stuck in the radiator rushes into the engine (we all know that throwing cold water on hot metal is a great idea), and in some cases will even make it through the engine cold enough to cause the thermostat to close again, causing the cycle to repeat.
With a bypass circuit, as long as your radiator is sufficient to dump as much extra heat as the engine is making, the engine should stay right around the thermostat temp, without major swings up or down. When it gets warmer, the stat opens and the radiator dumps the extra heat. When it gets cooler, the stat closes and the coolant just loops through the engine.
It's bad if your oil is too hot. But it's also bad if it's not hot enough. Being a water-cooled engine, the oil is only a secondary cooling method. I think it's more of a direct fix (as opposed to a band-aid on a symptom) to change the lame cooling system to something that will help the entire engine stay the proper temp. If everything else is in working order and your oil is still too hot, definitely add a cooler. But I don't think it's a good idea to just assume (without any data) that adding a cooler is an improvement over stock.