Best oil temp range

[david3921]

I'm thinking about installing a fan on my Rhino oil cooler. I installed the cooler after seeing that last years plowing was causing the motor to get pretty hot. Because of the length of the oil lines, I had to install the cooler high on the ATV where its not going to get much airflow, hence, the fan. I would rather not turn it on and off with a manual switch. I'm thinking of installing a thermal switch. Most come in 15 degree ranges and I found a supplier that has eight ranges. I've done some browsing to find the optional oil temperature for an air cooled single. As expected, there was a lot of opinions with consensus being that it should be around the 200 degree range. I can get a switch that turns on at 200F and off at 185F. I was leaning towards that one but started thinking that it would pretty much run all the time. Would the 210F/195F be better? Or would one even higher be the one to get?

[braindead0]

On air cooled engines, I've seen oil temps at high as 250 without any issue.

If the oil cooler doesn't have good airflow, I think no matter what you do the fan will likely be running often if not all the time. I think 210f and 195f should be fine, engine temps will be higher but at least with that range the fan might be off sometimes?

In the end anything is a guess until you get the fan on it and see, maybe buy a couple?

[Amateur]

Oil coolers don't need external airflow to operate as intended.

You're obviously basing your imagined ideal temps off of water cooled automobile thermostat temps. Don't do that.

[wheelbender6]

According to MotorTrend, dinosaur oil begins to break down at 275 deg F. Full synthetic begins to break down at 300 deg F. More at the link.
https://www.motortrend.com/how-to/en...0260%20degrees.

[david3921]

From what I've read, the viscosity of oil is determined at 212F for the single grade oils (i.e. 30W) and the second part of multi-weight oil (i.e. the 30 in 5W30). With that in mind, I'm going to install the higher 210F/195F switch. I'm currently not running synthetic as I've always liked Rotella T4, 15W40. I can go to the T6 if I still have issues.

[david3921]

Originally Posted by wheelbender6

According to MotorTrend, dinosaur oil begins to break down at 275 deg F. Full synthetic begins to break down at 300 deg F. More at the link.
https://www.motortrend.com/how-to/en...0260%20degrees.

But does this also apply to an air cooled motor running a different kind of oil? There is agreement with the break down temperature but it also talks about making sure that the motor runs at 212F to burn off the water. Jerry's Hawk was running around 170F oil temp in 90 degree weather;
http://chinariders.net/showthread.ph...t=Meter&page=2
According to the article, any water vapor wouldn't have burned off. I'm sure it does though as I think oil temps fluctuate in air cooled motor as it moves through the motor.

[david3921]

Originally Posted by Amateur

Oil coolers don't need external airflow to operate as intended.

You're obviously basing your imagined ideal temps off of water cooled automobile thermostat temps. Don't do that.

Do you mean natural air flow or a fan. I believe it may need something or it wouldn't have fins to increase the surface area. As for ideal temps, I want to make sure I'm not overheating when I'm plowing. I was last year so I am looking for experiences and information as to the range that the oil temp needs to stay within. I was looking at oil bypasses (that Megadan has suggested) but couldn't find any in a higher range. They are made for autos with the bypass temp at 180F.

[JerryHawk250]

Originally Posted by david3921

But does this also apply to an air cooled motor running a different kind of oil? There is agreement with the break down temperature but it also talks about making sure that the motor runs at 212F to burn off the water. Jerry's Hawk was running around 170F oil temp in 90 degree weather;
http://chinariders.net/showthread.ph...t=Meter&page=2
According to the article, any water vapor wouldn't have burned off. I'm sure it does though as I think oil temps fluctuate in air cooled motor as it moves through the motor.

I never had any issues with water vapor collecting in the oil. Most of the time it will run between 170-180 but does go 200+ in slow traffic and off road trails during 90* + temperatures. The oil temperature sensor is located on the oil drain port so that oil was cooled off by the oil cooler before entering the base. I'm sure the oil temp is a good bit higher once it passes through the head and valve cover.

[david3921]

Originally Posted by JerryHawk250

I never had any issues with water vapor collecting in the oil. Most of the time it will run between 170-180 but does go 200+ in slow traffic and off road trails during 90* + temperatures. The oil temperature sensor is located on the oil drain port so that oil was cooled off by the oil cooler before entering the base. I'm sure the oil temp is a good bit higher once it passes through the head and valve cover.

Yeah, I didn't think you did either. I'm in a bit of a holding pattern as the switch won't be here until next week. We had a little bit of wet snow here the day after Xmas but it's almost gone now. That gives we a bit more time before I will need to plow.