Can a dealer determine what weight oil your using?

[Patman]

I actually use this all the time when my friends ask if boutique oils are better. I always say “the real question is do you need better?”

That is true as well. A lot of the things we worry about on here are moot if the car isn’t going to be kept long enough to make use of the boutique oils or the high efficiency filters. I’m not saying that they don’t have their place because they certainly do, but sometimes taking a step back and putting things into perspective and finding out what the goal of the car owner really is can help simplify things.

 

[hemioiler]

Why is it worse? You mean a 20 grade? Not a shred of data here showing that anyone gets more life out of their vehicle just b/c they choose to run a higher grade oil than the manual calls for to sleep better at night. 2013 Ford Focus. Bought new. 5W20 for the last 12 years/135K/no oil consumption. Running a 30 was better right?

The point is not whether it is actually better, the point is whether you think it is better.

I absolutely think 5w-30 offers far more protection (especially while towing) in my truck. So why would I run around "damaging my truck" during the warranty period, just in case I might need it (statistically unlikely, and equally unlikely that they'd deny it anyway based on viscosity)?

I want the truck to run forever, so give it what it needs to best achieve that.

Yes "damaging my truck" is perhaps the wrong choice of words, it's more about increasing the chances of my truck living longer, (or "reducing wear" as another guy posted above), by running thicker oil.

 

[kschachn]

It's there to reduce wear. Feel free to argue lubrizon on verbage, which uses wear.
https://360.lubrizol.com/2019/Why-HTHS-Viscosity-Matters

Sure. But the warranty (which is what we are taking about here) is based on damage. Excessive untimely wear would no doubt constitute damage.

An oil with too low of a film thickness can cause rapid damage under some circumstances.

As far as an argument goes I’m not arguing with anyone. I’ll leave that up to you.

 

[radiometer]

Sure. But the warranty (which is what we are taking about here) is based on damage. Excessive untimely wear would no doubt constitute damage.

An oil with too low of a film thickness can cause rapid damage under some circumstances.

As far as an argument goes I’m not arguing with anyone. I’ll leave that up to you.

I very much appreciate your frequent comments on the value of HTHS and wear of our engines. It's obvious some are uncomfortable with your posts on this subject. If someone could offer facts that could stand up against your position on this I would take a careful look at it, but that has not been done so far. If my engines don't need a higher HTHS it certainly won't harm anything and maybe they might last a bit longer. When I recently purchased a new car for which 0W-20 was called for I had a talk with the service manager. He told me that my using a 5W-30 will not have any effect on my warranty.

 

[Fishstyx]

Was wondering if there's anyway an auto dealer can determine what weight oil your using?

Yes by sending in a sample to a lab for oil analysis especially if it’s under warranty and there’s an issue that is say questionable.