Overfilling oil: Just let it be, or take it back?

Yes take it back. You paid for service and should get the proper service. Wait too long and they'll think you're trying to pull a quick one of them. Engine will have to work harder to move the excess oil that you provided info on and cause it stress. I'm old school and want the best bang for my buck

 

I don't think that little overfill will affect anything. Just let it burn off. When bisco had his gen2, this was a regular occurrence with him, no harm, no foul

 

The place maybe had a hard time reading the dipstick? Best ploy is to just refill with the specd 4.5 US quarts (with filter change).

For best read, remove dipstick and wait a good 5 minutes before checking.

 

if you're never going to change it yourself, get a cheapo vacuum. takes ten minutes to suck out the excess through the dipstick.

 

Overfill stresses the gaskets and seals, which leads to oil leaks. Your call...

 

I'd guess they put in 5 quarts?

 

That's what they did when I gave them a 5 qt jug.

Now I give them 4 qts and tell them I'll top it up myself.

Posted via the PriusChat mobile app.

 

I guess I am the only one who remembers horror stories vividly. Reread this members experience w/ an overfill; granted its a Gen2 engine, but your Gen3 is designed to operate w/ oil between the two marks.
Another Walmart oil overfill, Toyota is hinting at new ICE | PriusChat

What's confusing? The oil is to be kept between the two marks for optimal operation; ideally keep the oil level at the top mark.
If oil is below the bottom mark of the dipstick, early engine death.
If oil is above the top mark of the dipstick, bad stuff might happen like the poor guy above.

Think lug nut. It has a specified torque value.

You under tighten it, the nut will likely work itself loose, BAD.
You over tighten it, the stud may break off b/c it is being overstressed, BAD.​

Just tighten the lug nut to the specified torque value and all will be well.

KEEP your oil level between the two marks, and all will remain well.

 

The problem with dipsticks is they can't measure the oil that isn't in the pan. When you put fresh (and cool) oil into an engine that may also be a bit cool, a lot of it is going to stick to the metal in the upper parts of the engine. This could be an extra half quart or more that isn't in the pan. So when you check after an oil change the dipstick reads full. Go on a long drive to get everything warmed up, then leave it parked overnight, and check the oil and it will be above full.

There will also be variations in readings if you're not parked on a flat surface.

With all this uncertainty, I would think a well designed car should be able to handle up to a quart of overfill without a serious problem.

On some of the new F-150s, you're not supposed to check the oil until after the truck has been sitting for 15 minutes. One guy did his own oil change and had 10 quarts come out of his 6 quart capacity engine and wrote about it here: Easy DIY Oil Change Holds a Minefield of Potential Screw-Ups - 2015 Ford F-150 Long-Term Road Test Note that a new engine was not required even though it had 166% of the specified amount of oil.

 

How? It doesn't increase oil pressure. That is set by a spring in the oil pump. If you overfill enough you can end up with "hydraulic lock". This requires you to almost fully fill the engine with oil. The engine will not turn over. Since he drove it home we know it's just fine running with a little extra oil. The only possible downside is if there is enough extra oil it can increase drag in the engine and the "splashing" of the extra oil can cause it to seep past vents etc a little more than usual. The amount reported doesn't sound like that will happen.

I would leave it. He actually got better value (extra oil for no extra cost).

 

The problem with over filling comes when moving parts start splashing oil causing it to foam. Any trapped air gets sucked into the oil pump causing it to cavitate. This is what I have been told and can't prove it one way or the other.

I looked around and found this.

What to Do If I Overfilled a Car With Oil | It Still Runs | Your Ultimate Older Auto Resource

 

Yeah I've found the level reading low, just after a fill. Being near-clear, and the smearing dipstick: doesn't help. Again, just drain well, put in the spec'd amount, check it more carefully a day or two later, first thing in the morning.

I think OP's instruction to the the "mom and pop" garage to get the oil on the top mark, coupled with the above vagaries, caused the overfill.

 

when my local guy overfills, he swears he puts in the spec. why would i put in more? it just costs me money.
but what he doesn't do is put in less, and check the dipstick.
most mechanics believe a little extra doesn't hurt anything, even though most manuals repeatedly warn against it.

 

I've heard this too, and it happens when the oil level reaches the crankshaft. However, it's not really an all or nothing thing, as you're driving up and down hills, going around corners, and hitting bumps, and all that is going to make the oil slosh all around. So the higher the oil level the more likely and more frequently the crank will hit the oil up until the point where the level is so high the crank is sitting in the oil with the engine off.

Of course, there's things you can do in the design of the engine to prevent this, such as baffles in the oil pan to limit the oil from sloshing around, or a windage tray under the crankshaft to limit oil splashing onto the crank (I was shocked to find out that our old Taurus had one of these, it also probably helps with aerodynamics inside the engine).

 

I'm sure a lot of people that have their oil changed never catch the overfill because that's the oil changes job right? (sarcasm)

 

Get yourself a Mityvac and you can easily solve problems like this yourself in about 5 minutes.

 

I usually overfill my Gen3 by about 1/4. Its tough to get it right. I put 4.4qt and it measures correctly. But then I drive around and on the next day it shows about 1/4 above.

I always get it right on the Gen2.

 

I have a difficult time reading the level, so with the 5 qt. jug I pour out the amount needed to get to the 4.x qts as noted in the manual. I wait a long time during draining, lower the car so it is flat on the floor, to make sure I get as much as possible out, and fill as prescribed. I don't waste time trying to read what I can't.

If you can read the level, and it would take a long time to bring the car back, I'd take it upon myself to drain about 0.5 qt out and measure the level again...

 

The Prius dipstick. Hard to read. Hard to see the oil. Never had a problem with any other car. Is it because the oil is so thin? I check the oil twice a month, in the morning, after the car has been sitting all night.

So Mendel, the secret is to pull out the stick, wait 5 minutes, then reinsert and check? I never see a distinct level on my dipstick... I just see kind of a blotchy smear. And I can't tell if it's overfilled, low, or what.