Why would it run cooler with SuperTech synth compared to Mobil1?

[ToyotaNSaturn]

Vehicle: Saturn Vue with the Honda 3.5L V6. Ran M1 in the previous fill for 3K, then put Supertech "full" synth 5w-30 this past week. I figure that running 3K OCI's for the first 20K or so is wasting money using M1, so I gave ST a shot. I was surprised at how the temp needle is on the low side of 3/8 temp. M1 ran just below 1/2 temp. Big difference, th only change is the oil. VERY surprising to me. This week's past cold weather and even with it warming up, it still doesn't run as warm compared to M1. Any hints as to why?

 

[tundra30]

The ST oil evaporating from your crankcase is having a "cooling effect" on the engine?

 

[DSteven]

I don't know exactly the differences between the M1 and the ST, except the M1 should be better (obvious). I have experienced the same thing with the 94 Corsica...it ran and heated up faster with Chevron Supreme 5W-30 than Castrol GTX High Mileage 5W-30 with 1/3qt of Lucas oil stabilizer. The obvious is thickness between the two. My friend also thought his caddy ran cooler on Mobil-1 10W-30 than M1 5W-30. Maybe there is a bit of viscosity difference between the two.

 

[haley10]

Are you looking at an actual analog oil temperature guage?? If not, it's probably irrelevant. The Super Tech is probably a 20wt. right now if it behaves like Castrol N/A syn does, so the resistance to flow will be less.

 

[cryptokid]

if you are looking at the water temp gauge then the oil has nothing to do with it. if you are looking at an oil temp gauge then i have no idea.

 

[ToyotaNSaturn]

quote:

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Originally posted by haley10: The Super Tech is probably a 20wt. right now if it behaves like Castrol N/A syn does, so the resistance to flow will be less.

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I don't know, This Ford Ranger UOA shows it holding it's viscosity pretty well...

 

[G-MAN]

quote:

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Originally posted by cryptokid: if you are looking at the water temp gauge then the oil has nothing to do with it.

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Please explain your statement. Oil can have an effect on the overall operating temp of an engine. I had a VW Scirroco that ran about 10 degrees cooler with Mobil 1 5w30 vs Castrol GTX 20w50. Oil temp gauge was about 20 degrees cooler.

 

[7TFord]

The fact that as well as the obvious lubricating factor the primary function of motor oil is to remove heat from the components may indicate that as suggested the Supertech being a possible 20wt is flowing better and removing more heat. It's hard to believe though that it would result in a noticeable change in operating temps. Yes, having an analog gauge in place and maybe more readings/experimentations being done over a period of time would be more scientific.

 

[Dr. T]

Engines are designed to work within a certain temperature range of normal....winter or summer. Even though different oil brands/grades may have an effect on the overall oil temperature, the engine running/coolant temperature will be whatever is determined as normal by the COOLING SYSTEM...ie. the thermostat primarily and then the rest of the cooling equipment. Unless you have an aftermarket temp. guage and ALL other parameters eg. ambient temp. are the same, it is probably not possible for you to accurately report that one oil or another caused a change in your coolant operating temperture.

 

[ToyotaNSaturn]

Not scientific by any means, I know, but the change in temp on the gage is noticeable.

 

[haley10]

Yeah, the Super Tech 10W-30 from your link held it's visc. very well.

 

[haley10]

Any speculation that a Group III w/ or w/o slack wax might exhibit some better flow characteristics at normal operating conditions?? It obviously doesn't look like a viscosity issue, like in G-Man II's example, which is clearly viscosity.

 

[JoggingGuy]

quote:

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Originally posted by tundra30: The ST oil evaporating from your crankcase is having a "cooling effect" on the engine?

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The PCV system is your friend

 

[rjundi]

Likely nothing to do with the oil. Has your heat control been on hot or on warm in the car. This has a more direct impact on water temp than the oil typically.

 

[rg144]

And thermostat could be behaving differently. Going back to M1 and seeing it go back up would be interesting at your next oil change.

 

[ALS]

I know with M1 in my car the oil temp's run 10 to 20 degrees cooler. All winter up until yesterday I couldn't get the oil temp above 160 degrees. Now since the temps are above 70 outside I'm seeing 175 to 180 degree operating oil temps. Which is normal for the M1. Water temps have not changed at all. Needle sits at 12 O-clock as always. With Pennzoil 10W30 the oil temps ran in the 190 to 210 range normally.

 

[Bob Miller]

"I was surprised at how the temp needle is on the low side of 3/8 temp. M1 ran just below 1/2 temp. Big difference, th only change is the oil. VERY surprising to me." Perhaps your oil filter was the culprit, high restriction.