Stop/Start reduces oxidation and wear

[BMWTurboDzl]

An episode with Lake Speed.

Clift notes

Stop/start reduces fuel dilution which reduces oxidation. Fuel dilution causes more wear than S/S.
Long drain oils can be formulated to initially drop in grade and rely on oxidation to increase viscosity as the miles accumulate
Low viscosity oils in many cases perform better in city cycle driving vs thicker grades. There's no difference in highway.
OE's slow down the rate at which oil moves through the engine when using thinner oils

 

[dnewton3]

Sample size of one does not make for science worthy of such conclusions. Anecdotal evidence at best.

Auto stop/start in this example gives zero indication of how many times that function happened relative to the total miles of the OCI. I find it very unlikely that a significant portion of this OCI was improved in terms of wear regarding using stop/start and it's supposed correlation to oxidation via fuel dilution.

WAY TOO MANY VARIABLES in this "test" to prove anything but YT videos intrigue the uninformed.

 

[ctechbob]

Interesting. His truck looks familiar. Looks to be a Ranger, which would be the 2.3 Ecoboost, so not a stranger to oil dilution.

I'll still be leaving mine off.

 

[ctechbob]

Screenshot of his UOA:

 

[BillyHW]

Does idling still increase fuel dilution if the engine has reached full operating temperature?

 

[daves87rs]

Stop Start simply restarts a warm engine. Also depends how long the engine stops.

 

[BigTimeTA]

1. Stop/start minimizes oil film thickness and invites boundary-lubrication incidents at each warm restart before oil film is reestablished again and again.. and again.
2. Increased wear metals that resulted from boundary-lubrication incidents WILL further accelerate oxidation cycles eventually as miles accumlate on the oil.
3. Bearing failure is 3-times more likely to take place in engines with start/stop systems.

 

[shortyb]

Lake Speed. Says it all . (Aren't he and Scotty Kilmer related?)

1. Stop/start minimizes oil film thickness and invites boundary-lubrication incidents at each warm restart before oil film is reestablished again and again.. and again.
2. Increased wear metals that resulted from boundary-lubrication incidents WILL further accelerate oxidation cycles eventually as miles accumlate on the oil.
3. Bearing failure is 3-times more likely to take place in engines with start/stop systems.

And is why I have over-ridden this "feature" on my latest VW and it stays in constant run mode from the start.

 

[captainbeandip]

I didn't watch the video and I'm not going to. Whatever it says in that video, I don't buy the argument that it makes the car last longer. That makes no sense. Starts and stops are what create most of the wear on stuff. Have you ever heard that highway miles are much easier on vehicles than city miles are? This is the same type of deal. You can go ahead and keep your start/stop if you want, and if you're happy for the extra .05 MPG that it gets you then so be it. I'm just not convinced that it's a worthy thing to have.

I do like the beefier batteries that they use though, so I am all for those. My 2018 vehicle that didn't come with start/stop is currently riding around with the battery that the slightly newer versions of that vehicle come with.

 

[skyactiv]

I wonder if you permanently disable start stop on a new vehicle if the starter will most likely last the life of the vehicle?

 

[atikovi]

You can go ahead and keep your start/stop if you want, and if you're happy for the extra .05 MPG that it gets you then so be it.

I don't care about the extra mpg, I just like the silence and smoothness at every stoplight.

 

[BMWTurboDzl]

Sample size of one does not make for science worthy of such conclusions. Anecdotal evidence at best.

Auto stop/start in this example gives zero indication of how many times that function happened relative to the total miles of the OCI. I find it very unlikely that a significant portion of this OCI was improved in terms of wear regarding using stop/start and it's supposed correlation to oxidation via fuel dilution.

WAY TOO MANY VARIABLES in this "test" to prove anything but YT videos intrigue the uninformed.

Well it's not a sample size of one as we're relying on the judgement from the tribologist. Lake Speeds statement was that there's a greater tradeoff on wear vis fuel dilution compared to stop/start. He also said that all engines have different wear characteristics. So if a engine isn't a known diluter then there may be no difference in wear. Obviously one way to mitigate fuel dilution is to go up a grade. This brings up a potential problem for owners who disable S/S but continue to use the recommended 20 grade oil.

 

[BMWTurboDzl]

1. Stop/start minimizes oil film thickness and invites boundary-lubrication incidents at each warm restart before oil film is reestablished again and again.. and again.
2. Increased wear metals that resulted from boundary-lubrication incidents WILL further accelerate oxidation cycles eventually as miles accumlate on the oil.
3. Bearing failure is 3-times more likely to take place in engines with start/stop systems.

Are you a tribologist? Because Lake Speed is a tribologist and what you're saying is counter to his claim.

 

[BMWTurboDzl]

I didn't watch the video and I'm not going to. Whatever it says in that video, I don't buy the argument that it makes the car last longer. That makes no sense. Starts and stops are what create most of the wear on stuff. Have you ever heard that highway miles are much easier on vehicles than city miles are? This is the same type of deal. You can go ahead and keep your start/stop if you want, and if you're happy for the extra .05 MPG that it gets you then so be it. I'm just not convinced that it's a worthy thing to have.

I do like the beefier batteries that they use though, so I am all for those. My 2018 vehicle that didn't come with start/stop is currently riding around with the battery that the slightly newer versions of that vehicle come with.

He didn't say anything about whether a car lasts longer. He did say that because of the oil film which remains on engine parts under S/S conditions (i.e. sitting at a red lights) there is comparatively less wear vs idle induced fuel dilution when S/S is turned off.

BTW..The MPG bump is quite significant. The fuel savings increases by the number of cylinders you have and if you're so inclined you can calculate it for your own engine.

 

[BMWTurboDzl]

I wonder if you permanently disable start stop on a new vehicle if the starter will most likely last the life of the vehicle?

The S/S starters are beefed up so I'd imagine that it should last the life of the vehicle. I'll let you know when the starter on my 4-series dies. I have had S/S disabled for most of its life.

 

[BMWTurboDzl]

I don't care about the extra mpg, I just like the silence and smoothness at every stoplight.

Don't forget air conditioning!!

 

[Thermo1223]

Don't forget air conditioning!!

My only gripe is it should be tied to outdoor air temp & a/c usage to not shut off on a 90F day.

 

[BMWTurboDzl]

Interesting. His truck looks familiar. Looks to be a Ranger, which would be the 2.3 Ecoboost, so not a stranger to oil dilution.

I'll still be leaving mine off.

I leave mine off as well. Can't stand the lack of air conditioning in our state of perpetual humidity.

 

[BigTimeTA]

Are you a tribologist? Because Lake Speed is a tribologist and what you're saying is counter to his claim.

And because he's a tribologist, he's supposed to be infallible? That's an ill logical argument.

https://journals.sagepub.com/doi/abs/10.1177/1468087418810094

 

[atikovi]

Don't forget air conditioning!!

The last few hybrid cars I've had came with electric a/c compressors so that's not an issue. Even with belt driven compressors the blower still blows with the engine off and there is enough cold in the evaporator for a few minutes of the engine off to keep the inside tolerable. Besides, if it gets too warm, the engine turns on automatically when requested by the climate control. You'll be more uncomfortable in the 2 minute walk from the parking lot to the supermarket on a 90° day than the 2 minutes at a red light with the engine off.