BrendanC
$100 site donor 2024
you trust a thin piece of stamped steel versus the volume an engineer specified? GM LT motors get 8 quarts. never touch the dipstick when servicing.
Overfilled from the factory?
- Thread starter Flatrate
- Start date
One doesn't exclude the other. The thing is that there is always at least 1/2 quart of the old oil remained in the engine. So overfilling with that amount every time is not really healthy for the engine.
I'n telling you because last time I overfilled with about that amount by mistake and my valve cover gasket started leaking. When I set the oil a bit below max. the leak stopped.
BrendanC
$100 site donor 2024
an overfill by .5 quarts is not going to make your valve cover leak. please thing about that statement and how oil has to get there.
My wife’s Subaru dealership always overfills on an oil change and other dealers do it too. I think it is some kind of “insurance” as many drivers don’t routinely check oil levels these days
Well, do you know how much the oil expands when heated to 212°F. Also how that is related to its volume and engine RPM too?
That's for sure. Everyone, always.
Patman
Staff member
It doesn’t expand that much actually. It’s not as if checking the oil cold vs hot shows a massive difference on the dipstick. In most cases it’s barely noticeable
BrendanC
$100 site donor 2024
again, you oil pump has to lift the oil to the top of the motor. that is steady state with rpm regardless of sump volume unless very low on oil and cavitation. could be hooked up to an oil sump the size of the ocean and it’s not going to change how much oil is in the top end of your motor.
Uh, yeah. Checks out.
Seriously, I bet it's muscle memory/culture/habit from all the years of one quart per 1000
- Joined
- Sep 22, 2025
- Messages
- 154
I personally have not experienced this. My complimentary first service included oil/filter, rotate tires and lube chassis on my Sierra 2500 L5T. When I was on level ground and the truck sat for about 30 minutes it was dead on the full mark. Same with the quick lube joint when I was injured some years back. Right at the full mark.
I check under the hood every fill up.
Of course this is anecdotal and YMMV.
CleanSump
Site Donor 2026
People keep relating that there is oil remaining in the engine. Folks, the engineers accounted for that when they put the volume of oil for a change in the manual. Stop worrying about it as it's irrelevant to an in-service oil change.
The dipstick, when read correctly and in the right conditions (fully drained back into the pan), should be the "final" say in checking the level.
BrendanC
$100 site donor 2024
i’m glad someone else has common sense….
I always thought the 'ideal' was right in the middle of the markings on dipsticks and most owners manuals say anywhere in between is perfectly fine. There's a segment of people that think if it's not touching the top or "Full" or "Max" mark that it's LOW on oil and must be topped off !
There really aren't going to be "pockets" where oil settles, if that's what people think. Oil does stick to walls and create a film but this isn't going to amount to much more than ounces in the grand scheme of things.
Many manuals put both the TOTAL OIL CAPACITY (new or rebuilt dry engine) and the oil amount required for oil and filter change.
But how many drivers bother to read that manual now. The fact that with the manual they also include a 3 page “quick start” comic book gives you a clue.
If they're changing their own oil, my money says the vast majority of them are in fact checking the manual.
But, in my experience the manual is not as accurate as using the dipstick for the final determination. I had a car that wouldn't drain almost a quart of oil when on the ramps. If I put in the amount in the manual it would be overfilled. Here's the thing. Why do you think they put the dipstick there? Do they expect you to ignore it? I doubt it.
So, the dip stick is not designed and calculated by those same engineers?
Does it matter ir does it say jn the manual how long to wait until all the oil is drained from the engine, so then it's ready for the quantity mentioned in those same manual?
The thing us that different people wait different time for the oil to drain. Usually, people who overfill are those who don't wait enough.
Last edited:
My comment was STRICTLY in response to them saying people don't read manuals. In another post, I advocated that the dipstick is the FINAL say in determining the level. To me, the manual amount is a guideline or starting point though. On my old car, the manual said 5.25 quarts with oil change and filter change. For 6+ years, I dumped a 5 quart bottle in and it was in the middle of the marks so I no longer cared what the manual said.
I do the same—I change my oil when car's front is a bit jacked up on stands. It's not horizontal. That may contribute for some oil unable to be poured out vs people who change their oil when their car is completely horizontal as on a lift.