Time for oil to reach operation temperature

[ron in sc]

I have been using Mobil 1 15W50 in 1997 Porsche since new.

Changed to Motul 15W50. I've driven the car several times since the change and each time the oil reaches operation temperature sooner. I drive the same route for warm up of oil for many years.

So what is going on here, just normal?

 

[oldhp]

Maybe the Motul 15W50 is thicker at lower temps causing engine to work harder, which would in turn warm up faster?

 

[dparm]

Originally Posted By: oldhp
Maybe the Motul 15W50 is thicker at lower temps causing engine to work harder, which would in turn warm up faster?


I was thinking the same thing, but they're almost exactly identical.

300V's HTHS is 5.3 to M1's 4.5, however, which is about 15%.

 

[ron in sc]

Originally Posted By: oldhp
Maybe the Motul 15W50 is thicker at lower temps causing engine to work harder, which would in turn warm up faster?


Would that account for it cooling down faster? I think it cools faster but I'm not positive on that; it's hard to judge that.

 

[edyvw]

Originally Posted By: dparm
Originally Posted By: oldhp
Maybe the Motul 15W50 is thicker at lower temps causing engine to work harder, which would in turn warm up faster?


I was thinking the same thing, but they're almost exactly identical.

300V's HTHS is 5.3 to M1's 4.5, however, which is about 15%.

That is not small difference.

 

[Clevy]

OP

perhaps due to motul being a group 4/5 basestock oil it helps absorb and dissipate heat faster that the M1 you were using before.
I've used motul 300V in my Harley before and it among my 3 favorite oils ever used in my bike.
Just monitor your gauges and enjoy the ride

 

[turtlevette]

Originally Posted By: Clevy

perhaps due to motul being a group 4/5 basestock oil it helps absorb and dissipate heat faster that the M1 you were using before.


That's what I was thinking. A different oil makeup will probably have a different specific heat.

 

[Shannow]

Specific heats are all pretty close.

Engines have to perform work against an oil to "shear" it, so thicker oil will take more work, and heat quicker.

 

[turtlevette]

Originally Posted By: Shannow
Specific heats are all pretty close.

Engines have to perform work against an oil to "shear" it, so thicker oil will take more work, and heat quicker.


Agreed.

Would a thinner oil have a lower steady state operating temperature? Or is it negligible?

Say my vette runs 3500 rpm at 70 mph. That would be enough rpm to be significant compared to the new cars that run around 1800rpm at 70.

If so that's another reason to go to a thinner oil. I've got Valvoline 0W-20 in it now.

 

[Clevy]

Originally Posted By: turtlevette
Originally Posted By: Shannow
Specific heats are all pretty close.

Engines have to perform work against an oil to "shear" it, so thicker oil will take more work, and heat quicker.


Agreed.

Would a thinner oil have a lower steady state operating temperature? Or is it negligible?

Say my vette runs 3500 rpm at 70 mph. That would be enough rpm to be significant compared to the new cars that run around 1800rpm at 70.

If so that's another reason to go to a thinner oil. I've got Valvoline 0W-20 in it now.










If your chevette is spinning at 3500rpm at 70mph you've got 4.60 gearing, or 5.11s in the rear and that car is seriously heating the oil up and no way would going thinner be advisable.
If anything a 40 grade is the bare minimum at those sustained rpm,unless you've got an oil cooler which is pretty much a must have if you're spinning a v8 at those rpm at highway speeds.
Heck even a 50 grade.
I'm going to experiment on my way home tonight. At 3500 rpm in my charger in 3rd gear I'm likely close to that 70mph. I'll try it out and see where my oil temps stabilize,just to get a rough estimate of what your running for oil temps.
At those rpm I'm sure my oil pump is bleeding off the excess pressure since at 2000rpm,I'm at 50psi oil pressure. It spikes up to 60,maybe 65 pounds and doesn't increase anymore from there.
I have 3.90s in my 2000 mustang and at 70mph I'm spinning at 2300rpm. So 3500 rpm means there is a whole lotta gear in that rear.
That is of course if this isn't some work of fiction.

 

[turtlevette]

Originally Posted By: Clevy
If your chevette is spinning at 3500rpm at 70mph you've got 4.60 gearing,


Good job. 4.56/1 with 700R4 .7/1 OD. That has the rear pinion spinning at 5K for hours at a time.

I've never had a diff that got so hot you can't touch it. And you can smell the diff gear oil when it gets hot.

At 6300 rpm the rear pinion is spinning a hot 9K. Up at Mosport on the Mario straight.

 

[Doug Hillary]

Hi,
ron in sc - How did you obtain the oil's temperature?

 

[ron in sc]

Originally Posted By: Doug Hillary
Hi,
ron in sc - How did you obtain the oil's temperature?
Doug,

By using the oil temperature gauge. It has hash marks on it and by the position of the needle you can get a very good estimate. That said I don't know offhand where the oil temp sensor is located in the engine. The first hash mark past zero hash mark equates to 50 degrees C, with the oil pressure very nearly 5 bar at 3500 rpm and probably same pressure at lower rpm too.

Owners manual says not to exceed 4200 rpm for first 5 minutes but I don't go above 3500 rpm until I see 50 degrees C. I generally don't drive it hard until temp is getting near to 90 degrees C. Of course as ambient temp increases so does oil temperature. The reverse is also true; as ambient decreases oil temps decrease too. I've seen oil temps as high as approximately 120 degrees C. Of course car does have an oil cooler with a fan. Also have an oil fan override switch so I can turn on oil cooler fan if stopped in traffic and temp begins climb.

At last oil change with filter I with car took 12 L.

Ron

 

[glxpassat]

My guess would be the Motul is thinner when cold and more is getting circulated through the engine rather than getting dumped back into the pan by the relief valve.

 

[ron in sc]

Originally Posted By: glxpassat
My guess would be the Motul is thinner when cold and more is getting circulated through the engine rather than getting dumped back into the pan by the relief valve.


I don't know if it makes any difference but there is no pan. It is a dry sump motor with an oil tank that holds about 8 L.

 

[glxpassat]

Ron, I think it would work the same because if there were no relief valve the pressure would be so high that it could blow off the oil filter. But I know nothing about dry sumps...

 

[glxpassat]

I just read Motul's data sheet and it stated it was made from an ester base, so it probably has a different specific heat. The viscosities are basically the same as M1.

 

[SXE10]

I'm confused, you're comparing M1 15W50 & 300V 15W50 an wondering why the Motul is better?? Ester deals with heat better than any other oil.

I changed from M1 5W30 to 300V 5W30 late last year. The difference is like night & day. More oil pressure, smother power delivery etc etc. Made my 90K mile engine feel like new again