Does Synthetic Oil have a Break-in Period?
#1
Does Synthetic Oil have a Break-in Period?
My last two cars have had nothing in them except Mobil One synthetic.
On my TCH, which has had only 0W-20 in it, I just went throught the first oil change, and my first tank afterward showed a decrease of approximately 2 MPG over the same commute that I have gotten 44 MPG on since I got the car. The second tank after the oil change is now showing an FE improvement and I am back to 43 MPG.
My wife's Forester uses 5W-20, and during the last three oil changes I have noticed that the FE dropped from 28 MPG down to about 26 MPG for her commute. It came back up again after a refuel or two to what it was before.
I wonder if synthetic oil, or at least Mobil One, needs a to get hot before it gets stable -- maybe a "break in" period. Anyone else noticing anything like this?
On my TCH, which has had only 0W-20 in it, I just went throught the first oil change, and my first tank afterward showed a decrease of approximately 2 MPG over the same commute that I have gotten 44 MPG on since I got the car. The second tank after the oil change is now showing an FE improvement and I am back to 43 MPG.
My wife's Forester uses 5W-20, and during the last three oil changes I have noticed that the FE dropped from 28 MPG down to about 26 MPG for her commute. It came back up again after a refuel or two to what it was before.
I wonder if synthetic oil, or at least Mobil One, needs a to get hot before it gets stable -- maybe a "break in" period. Anyone else noticing anything like this?
Last edited by FastMover; 08-29-2007 at 01:53 PM.
#2
Re: Does Synthetic Oil have a Break-in Period?
My last two cars have had nothing in them except Mobil One synthetic.
On my TCH, which has had only 0W-20 in it, I just went throught the first oil change, and my first tank afterward showed a decrease of approximately 2 MPG over the same commute that I have gotten 44 MPG on since I got the car. The second tank after the oil change is now showing an FE improvement and I am back to 43 MPG.
My wife's Forester uses 5W-20, and during the last three oil changes I have noticed that the FE dropped from 28 MPG down to about 26 MPG for her commute. It came back up again after a refuel or two to what it was before.
I wonder if synthetic oil, or at least Mobil One, needs a to get hot before it gets stable -- maybe a "break in" period. Anyone else noticing anything like this?
On my TCH, which has had only 0W-20 in it, I just went throught the first oil change, and my first tank afterward showed a decrease of approximately 2 MPG over the same commute that I have gotten 44 MPG on since I got the car. The second tank after the oil change is now showing an FE improvement and I am back to 43 MPG.
My wife's Forester uses 5W-20, and during the last three oil changes I have noticed that the FE dropped from 28 MPG down to about 26 MPG for her commute. It came back up again after a refuel or two to what it was before.
I wonder if synthetic oil, or at least Mobil One, needs a to get hot before it gets stable -- maybe a "break in" period. Anyone else noticing anything like this?
I've got some charts showing what happens with transaxle oil:
The same appears to happen with engine oil.
Bob Wilson
#3
Re: Does Synthetic Oil have a Break-in Period?
My TCH is coming up to its first oil change. My dealer will provide the first one free. Did you do yours at the dealer? Will they put in 0w20? Also, do you know for sure that the oil in your new camry was indeed 0w20. I would be depressed if my mpg drop cause of a different oil grade. The location of the filter and plug is very accessible. I am however somewhat hesitant on doing it myself for warranty purposes.
If you are doing your own oil change, are you not concerned about warranty. I have seen a post that recommend buying the oil and filter from Toyota so that warranty denial can be avoided. That's just hard to fathom. Thoughts anyone?
Last edited by rocko0002; 08-29-2007 at 05:29 PM.
#4
Re: Does Synthetic Oil have a Break-in Period?
Although there can be some competing factors pulling the viscosity in different ways, engine oil tends to become more viscous through its lifetime. I'm reminded of a study on engine oil life of Amsoil and Mobil 1 synthetic oils. In general, both of these samples' viscosities increased with their lifetime.
As for the competing factors, I pulled the following description from here:
Contamination from wear or debris increases the viscosity. Incomplete combustion, fuel leaks, coolant leaks, overheating, additive loss and detergent breakdown tend to decrease the oil viscosity before complete failure cooks the lubricant causing its viscosity to increase.
As for the competing factors, I pulled the following description from here:
Contamination from wear or debris increases the viscosity. Incomplete combustion, fuel leaks, coolant leaks, overheating, additive loss and detergent breakdown tend to decrease the oil viscosity before complete failure cooks the lubricant causing its viscosity to increase.
#5
Re: Does Synthetic Oil have a Break-in Period?
Although there can be some competing factors pulling the viscosity in different ways, engine oil tends to become more viscous through its lifetime. I'm reminded of a study on engine oil life of Amsoil and Mobil 1 synthetic oils. In general, both of these samples' viscosities increased with their lifetime.
. . .
As for the competing factors, I pulled the following description from here:
Contamination from wear or debris increases the viscosity. Incomplete combustion, fuel leaks, coolant leaks, overheating, additive loss and detergent breakdown tend to decrease the oil viscosity before complete failure cooks the lubricant causing its viscosity to increase.
As for the competing factors, I pulled the following description from here:
Contamination from wear or debris increases the viscosity. Incomplete combustion, fuel leaks, coolant leaks, overheating, additive loss and detergent breakdown tend to decrease the oil viscosity before complete failure cooks the lubricant causing its viscosity to increase.
Thanks,
Bob Wilson
#6
Re: Does Synthetic Oil have a Break-in Period?
Although there can be some competing factors pulling the viscosity in different ways, engine oil tends to become more viscous through its lifetime. I'm reminded of a study on engine oil life of Amsoil and Mobil 1 synthetic oils. In general, both of these samples' viscosities increased with their lifetime.
Last edited by FastMover; 08-30-2007 at 02:09 PM.
#7
Re: Does Synthetic Oil have a Break-in Period?
Since you mentioned oil filter, let me throw one more variable into the thought process.
When you put a fresh filter on the car, the oil should be flowing through the media. Then as the oil starts to accumulate particulate, it starts to clog the filter, and the force required to push it through the media increases. Suddenly the force is greater than that required for the relief valve and the oil starts to bypass the media. Now that it has started to pypass the media, the relief valve does not require as much force to stay open, and the net result is it requires less force to go through the bypass route than it did in the new filter media resulting in less drag on the oil pump and better fuel economy.
Just a theory, but I really hope it is not true as it would mean the oil filters on most all cars don't really serve any useful purpose.
When you put a fresh filter on the car, the oil should be flowing through the media. Then as the oil starts to accumulate particulate, it starts to clog the filter, and the force required to push it through the media increases. Suddenly the force is greater than that required for the relief valve and the oil starts to bypass the media. Now that it has started to pypass the media, the relief valve does not require as much force to stay open, and the net result is it requires less force to go through the bypass route than it did in the new filter media resulting in less drag on the oil pump and better fuel economy.
Just a theory, but I really hope it is not true as it would mean the oil filters on most all cars don't really serve any useful purpose.
#8
Re: Does Synthetic Oil have a Break-in Period?
Nope. Where I work we can do a crude check for metal and for filtered materials in oil (we cannot check viscosity, however). Very low metals count of less than 0.01 PPM, no foreign matter for both vehicles. Certainly nothing that would open the bypass.
#10
Re: Does Synthetic Oil have a Break-in Period?
When you put a fresh filter on the car, the oil should be flowing through the media. Then as the oil starts to accumulate particulate, it starts to clog the filter, and the force required to push it through the media increases. Suddenly the force is greater than that required for the relief valve and the oil starts to bypass the media. Now that it has started to pypass the media, the relief valve does not require as much force to stay open, and the net result is it requires less force to go through the bypass route than it did in the new filter media resulting in less drag on the oil pump and better fuel economy.
Most likely the oil does have a breakin period as some of the long HC chains will shear and lower the viscosity after a few hot/cold cycles. IIRC non petroleum base sythetics have less of a break in.
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