Yesterday it was pushing 95 deg F here in Northern Alabama. It was time to mow the lawn, so out came the '94 vintage John Deere STX38 with the 12.5HP Kohler engine and hydrostatic transmission. I use 10W-30 oil, mostly Mobil1 but have put the odd half-quart of left-over dino 10W-30.
Since it was so hot, I got out the infrared heat gun and took the temperature of the outside surface of the oil filter as I was mowing. (Yes, I targeted the NAPA sticker, not the shiny can, knowing that the IR gun won't work on shiny surfaces.)
After about 30 minutes, it had hit 200 deg F.
After about 60 minutes, it had hit 225 deg F.
When I finally pulled into the garage after an hour and a half of mowing, it was reading 250 deg F. I could feel the heat radiating off of the engine itself.
I let the engine run at full throttle with no load for about 5 minutes in the garage. The temperature remained close to 250 degrees F. I was curious to see if 5 minutes of no load would drop the oil temp.
I was both surprised and not surprised that it had gotten this hot. On one hand, I know small engines that air-cool don't have active temperature control, so I'm not shocked. As we hit warmer weather, the engine will naturally run hotter. Yet, on the other, I'd never have guessed it would hit 250 deg F, as I would have though it would have sufficient cooling to not get that hot.
I've always been an advocate for quality oils in air-cooled equipment and personally have always run Mobil1. With the Mobil1, I can run a full season (50 hours or so) with the oil staying very clean. In fact, it almost looks too good to change at the 50 hour mark. But since it sits all Winter, I always change the oil/filter in the Spring regardless of appearance. It takes maybe 2.5 quarts and the NAPA Gold filter is under $5 from site sponsor Fleet Filter.
Now that I've seen this result, I have just a little bit more data to back up advocating quality oils for air-cooled small engines. Note that I'm not saying that a cheap oil wouldn't work as well, I'm just saying that I feel more comfortable using what I use.
thanks much,
ben
Since it was so hot, I got out the infrared heat gun and took the temperature of the outside surface of the oil filter as I was mowing. (Yes, I targeted the NAPA sticker, not the shiny can, knowing that the IR gun won't work on shiny surfaces.)
After about 30 minutes, it had hit 200 deg F.
After about 60 minutes, it had hit 225 deg F.
When I finally pulled into the garage after an hour and a half of mowing, it was reading 250 deg F. I could feel the heat radiating off of the engine itself.
I let the engine run at full throttle with no load for about 5 minutes in the garage. The temperature remained close to 250 degrees F. I was curious to see if 5 minutes of no load would drop the oil temp.
I was both surprised and not surprised that it had gotten this hot. On one hand, I know small engines that air-cool don't have active temperature control, so I'm not shocked. As we hit warmer weather, the engine will naturally run hotter. Yet, on the other, I'd never have guessed it would hit 250 deg F, as I would have though it would have sufficient cooling to not get that hot.
I've always been an advocate for quality oils in air-cooled equipment and personally have always run Mobil1. With the Mobil1, I can run a full season (50 hours or so) with the oil staying very clean. In fact, it almost looks too good to change at the 50 hour mark. But since it sits all Winter, I always change the oil/filter in the Spring regardless of appearance. It takes maybe 2.5 quarts and the NAPA Gold filter is under $5 from site sponsor Fleet Filter.
Now that I've seen this result, I have just a little bit more data to back up advocating quality oils for air-cooled small engines. Note that I'm not saying that a cheap oil wouldn't work as well, I'm just saying that I feel more comfortable using what I use.
thanks much,
ben