Does an engine run cooler with Syn in it?

Status
Not open for further replies.
Joined
Mar 7, 2009
Messages
453
Location
northeast
I changed my oil to a syn blend and it seems to be running a few degrees degrees cooler. According to temp gauge ..Is that possible?
 
Last edited:
Originally Posted By: lucerne06
I changed my oil to a syn blend and it seems to be running a few degrees degrees cooler. According to temp gauge ..Is that possible?

Yes, it is possible.
 
Originally Posted By: Mark888
Originally Posted By: lucerne06
I changed my oil to a syn blend and it seems to be running a few degrees degrees cooler. According to temp gauge ..Is that possible?

Yes, it is possible.


X2.

BuickGN is right that your t-stat and coolant control the temp BUT... The t-stat has a temp that it opens at but that does not mean the coolant stays at that temp. A t-stat may open at say 195 but the engine can actually run at 205-210. Synthetic oil, which reduces friction that causes heat, can lower operating temp a little. Remember that the coolant heats up from the friction and combustion of the engine running.

If you run something like Royal Purple's Purple Ice or Redline's Water Wetter you can reduce operating temp even further. You will only reduce it to the temp at which the t-stat opens at though. If it lowered it more than that the t-stat would close causing the engine to heat back up.
 
Last edited:
Originally Posted By: GMBoy
My Harley dropped 10 degrees on Redline Synthetic.


Air cooled or liquid?
 
In a liquid cooled engine the heat is generated and mitigated in the head and cylinder block by the coolant. Oil will do some cooling there, but much less than circulating coolant. Oils role more important in the bottom end, here only cooled by oil, and lesser friction may help. Most friction is the cyl/rings, and this is largely loaded into the coolant not the oil. 5-10 degrees lower coolant temp if that may be possible, more likely in a air cooled engine, here oil is more important secondary cooling factor. Total heat loading is the same just the portion going into coolant vs. oil.
 
Originally Posted By: NHHEMI
Originally Posted By: GMBoy
My Harley dropped 10 degrees on Redline Synthetic.


Air cooled or liquid?


I don't think Harley makes any liquid cooled bikes.
 
I`m a firm believer that it does too. My car`s temp gauge always stays on the 1/4 mark when I use Mobil 1 15W50 silver cap. All other oils it usually stays right underneath the halfway mark. Another thing I notice when using it,is that the top end of the engine where the cam shafts are (it`s a DOHC) always stays cooler to the touch after a long drive with this oil. Dunno if it`s all in my head but whenever I change oils and go back to that particular one,the same trend takes place. My engine also runs cooler on thicker oils.
 
Originally Posted By: Mark888
Originally Posted By: lucerne06
I changed my oil to a syn blend and it seems to be running a few degrees degrees cooler. According to temp gauge ..Is that possible?

Yes, it is possible.
How is it possible?
 
I don't know if an engine runs cooler with syn. Conceptually I suppose it could, given better flow and reduced friction.

Back in the early 70's had a Yamaha 500cc bike (4 stroke air-cooled, big bore, short stroke engine) that would stall and practically sieze up in the summer on hot days when driving in traffic. The conventional oil just cooked and the internal friction due to heat bogged the motor down till it stalled and wouldn't start again till it cooled down. I couldn't even kick or electric start it since the engine was just too tight to crank. I switched to Mobil 1 Synthetic and the problem went away. Did the engine run cooler? Perhaps. I think that M1 simply had better lubrication properties at high temps and could tolerate the excessive heat without cooking into a thick goo.
 
Last edited:
Originally Posted By: GMBoy
My Harley dropped 10 degrees on Redline Synthetic.


Mine dropped about the same easily. It was noticable. Right now I am running a fill of Lubeatech 20w50 and it runs very cool.
 
Last edited:
I don't believe you'll ever see a difference in the indicated operating temperature of a *liquid* cooled engine due to using synthetic vs. conventional oil. As others have said, the thermostat regulates coolant temperature, and even if you could magically wave a wand and make the engine internal friction zero, the coolant would still run the same temperature due to the fact that the combustion process dumps far more heat into the coolant than the friction of oil lubricated parts does (by orders of magnitude!)

That's not to say that there is less HEAT rejected to the atmosphere if you use a synthetic, assuming that the synthetic really reduces internal friction (questionable, given how good today's conventional oils are). But that is different than saying that the engine "runs cooler."
 
Last edited:
Status
Not open for further replies.
Back
Top Bottom