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The only effect that a little more oil has is of course the temperature, which does not rise as quickly. But the calculations don't take the fill level into account. I think the effect is more cosmetic but I wouldn't top up to the maximum -- on any car.
I'm sure they're assuming some fixed volume for the oil rather than updating that based on the dipstick readings.
Running more oil will definitely help with oil life to some extent: at minimum the contaminants created by driving are distributed through a larger volume of oil, and it helps keep oil temperatures down. That said, on a Cayman where full is ~8qt and the low line is ~7qt you've got a lot of oil so I doubt it matters much. Other cars I always keep at full, the 987.2 I keep at one notch below full because I was getting excess oil in the intake otherwise.
As an example, the wife's Mini is like 4qt full and 3qt minimum. That's a much bigger difference, and with the turbo those cars all burn some oil. Folks get in trouble because they don't check it and drive around at or below the minimum, and then the oil gets really nasty from the heat and contamination. The best thing you can do on those cars to prolong engine life is to check the oil once a month and keep it at the top line.
Full or not quite full can also be affected by oil pan depth and piston orientation. Couldn't agree more on the idea that oil quantity being at the high mark might be better for many cars. But our flat 6 design with shallow oil pan doesn't favor that IMHO.
On another note ... I had Covid 14 months ago (thank you AT&T cable guy!!!). I thought I was fine until I realized I couldn't lay out stair stringers in my head while rebuilding a friend's backyard. Realizing this, I started running the normal calculations I've always done in my head and ... oops. I'm guessing my memory faded for a while as well. I thought I had air filters, poly V belt, and plugs coming due. I went to my service chart and realized I did all of this and more just a year ago. So, while I bought a borescope to look into my cylinders, I'm not due to have my plugs out for a while still. Since modern plugs have sacrificial coatings (do not use anti seize), they are not reusable, so I won't be doing this check for some time. Sorry to those who were expecting me to post pictures soon.
Last edited by Wayne Smith; 02-12-2024 at 03:47 PM.
Since modern plugs have sacrificial coatings (do not use anti seize), they are not reusable, so I won't be doing this check for some time. Sorry to those who were expecting me to post pictures soon.
You can reinstall modern plated plugs and I've done so many a time. As long as the threads are still shiny then the anti-seize plating is there and they're likely fine. There's also an NGK tech doc somewhere that says you can use anti-seize when reinstalling used plugs as a replacement for the plating, you just have to mind the amount and use the low end of the torque spec.
The "don't use anti-seize" advice from the manufacturers is sound: with modern thread plating it's not needed for new plugs and I never use it on fresh plugs any more. It's easier for manufacturers to just keep things black or white because it reduces potential issues, but the reality of working on cars can be more gray. Assuming you KNOW WHAT YOU ARE DOING (which the vast majority of people installing spark plugs do not) then anti-seize on plugs is perfectly fine in some cases.
If there's any question or you don't trust yourself just get new plugs.
You can reinstall modern plated plugs, and I've done so many a time. As long as the threads are still shiny then the anti-seize plating is there and they're likely fine. There's also an NGK tech doc somewhere that says you can use anti-seize when reinstalling used plugs as a replacement for the plating, you just have to mind the amount and use the low end of the torque spec.
The "don't use anti-seize" advice from the manufacturers is sound: with modern thread plating it's not needed for new plugs and I never use it on fresh plugs any more. It's easier for manufacturers to just keep things black or white because it reduces potential issues, but the reality of working on cars can be more gray. Assuming you KNOW WHAT YOU ARE DOING (which the vast majority of people installing spark plugs do not) then anti-seize on plugs is perfectly fine in some cases.
If there's any question or you don't trust yourself just get new plugs.
Let me stress ... This is not intended to start a fight. This is IMHO only ...
I (almost) agree with everything you say. But I would hesitate to state such to an unknown public audience!!! So ...
There are those who will argue that anti seize impairs electrons. But antiseize was common in the "old" days, even with half the electrode voltage, and motors ran fine. So I'm pretty much OK here. However, reading about people breaking plugs or pulling out threads with antiseize needs to be noted. How much should torque be reduced so the plug is the right amount of secure? (Re)user beware!!!!
I've had plugs creak and groan all the way out on these cars. For me, that's scary. Aluminum heads are soft and fragile, IMHO. I'd just as soon throw out plugs rather than risk having a rough edge on the reused and possibly compromised plating catch a thread, with or without antiseize. So I'll opt to not reuse. That's me, not everyone. No judgement on my side as to your choice. Full disclosure ... When I was younger with little money, I reused plugs after cleaning them ... many times. So who am I to talk?!?!?!
To be clear, as I started this reply with ... I (almost) agree with everything you say.
No, totally get what you're saying. Like I said, you have to REALLY know what you're doing. But as long as you know the logic behind the rules sometimes it's okay to break them. For the record, here's what NGK was saying, at least a few years ago:
Manufacturers will err on the side of the simplest instructions that will prevent the majority of folks from messing up. If that means throwing away a perfectly good set of plugs, heck, they're not paying for it: they just don't want to get sued or be on the hook for warranty repairs that are not their fault.
02-12-2024, 02:35 PM
