Oil Overfill Question

Significant engine oil overfilling could lead to an mpg decrease and engine start problems.

My guess is that 5 quarts of oil were added to your car.

FYI, $30 is about right for an engine oil and oil filter change at a Toyota dealer. $65 is a rip-off price.

 

I would not use that dealer again. They are a toyota dealer, the Prius is a toyota product, so all the service staff including the service advisor should know about the Prius idyosciouses ( damn I wish i could spell LOL). The first oil change for my Prius I was introduced to the Prius tech and HE told me I was smart to come to them for oil changes ect. and went on to explain about not overfilling the oil ect.

 

Half an inch works out to about 0.5 quarts over. Standard Toyota fill is 3.9 quarts, and this results in about 0.2-0.25 quart overfill, roughly 1/4 inch. Toyota delivers them from the factory overfilled. Some techs round 3.9 to 4 making the problem slightly worse. If Toyota was paying attention to this, they would simply give the techs a target instead of a capacity. The target should be less than capacity. Also, Toyota really should update their capacity figure as it doesn't match the dipstick. Perhaps the dipsticks they are shipping in all of the cars are wrong, but more likely the capacity calculation is a bit off.

The span from full to low on the dipstick is 1.6 quarts (per Toyota) over a little less than 1-3/4 inches. Granted this is not completely linear but over short ranges it will provide a decent approximation.

There is undoubtedly some safety margin above and below the fill lines on the dipstick...how much is anyone's guess. There was another poster recently who had a large overfill (how much is unknown). In that case oil was actually being blown over into the throttle chamber and producing an error code for one of the cylinders.

 

Idiosyncrasy, from Greek ιδιοσυγκρασία, idiosunkrasia, "a peculiar temperament", "habit of body" (idios "one's own" and syn-krasis "mixture"). It is defined as an individualizing quality or characteristic of a person or group, and is often used to express eccentricity or peculiarity. (idiosyncrasies)

Thanks to reference.com

Yes the prius can be a bit idiosyncratic. It prefers engine oil not overfilled, tires not underfilled, and fuel tank not empty. In most other respects it is quite easy to get along with.

 

write toyota with your story. they need to know the BS being put out buy the staff at that dealer; plus send copy to president of company that owns dealership. we only get better service by informing everyone what is going on!

 

Very true! I noticed that after my first two oil changes at a dealer that they routinely overfilled the oil. I also noticed a rapid decrease in mpg. After those experiences, I told the dealer specifically "not" to overfill the oil, and the reasons why. They complied, and my mpg increased by at least 4-5 mpg.

 

Ok, at that point I would have had to restrain myself from smacking him upside the head.

And I would never let him work on my car again.

 

Unfortunately its not just car dealerships! :fear:

 

Assuming that the dipstick is correct, why th' heck has Toyota not corrected the shop manual after five years? 3.9 quarts (which is stated in the owner's manual as the *dry capacity* of the system including filter) is simply too much to add at an oil+filter change, because it does not allow for the residual oil remaining inside the engine.

The certain way of avoiding an overfill is to buy 3 (three) quarts of oil yourself, hand them to the service writer/oil change tech and tell them to use that and no more. Three quarts is plenty at an oil+filter change; it leaves the level about halfway between the ADD and FULL marks on the dipstick.

And always check the level yourself before driving away from any oil change, no matter who does it. This can find many gross mistakes before they become annoying and/or expensive.

 

I just checked my oil today and noticed it is about a half inch over the full dimple. I would like to get it to the normal level (i read it should be about 1/4 inches below the full dimple. Does anyone know of an easy way to take out some of the oil? Thanks!

 

Most marine stores sell hand operated vacuum pumps designed to drain oil through the dipstick. They work as well or better than using the drain plug. Around $30.

Or find a good shop that works on German cars,,, most German cars are spec'ed to drain from the dipstick, and a good shop will have a pump and might do it for you. You could always, loosen the plug and let a few CC's drip out into a pan, then retighten the plug. Watch for leaks after since you won't be using a new crush washer.

Icarus

 

Thanks for the response. Are there any significant losses for having my oil level a half inch over full?

 

Changing the oil/filter in a Prius is very easy and can almost be done without ramps (straddle a ditch and crawl under with your oil pan, appropriate socket to fit drain, small oil wrench, and filter...
install a Fumoto valve...

fumoto oil drian valves

...and in the future you can regulate and change oil from the bottom with ease and without a socket wrench. You can also get every last drop of that dirty stuff out!

PS, document oil and filter purchases and install dates for warantee issues.

 

Vacuum pump,, from a marine dealer ~$30 works slicker than snot,,, gets every last drop out,, you don't have to mess with the drain plug or install fumoto valve,,, which could accidently open.

Pump it out, spin off the filter,, you don't even have to get one hand dirty.

Icarus

 

Whatever suits you...I'm no salesman or stockholder but Fumotos don't leak and "according to their site" and my experience with using them they won't leak.

 

My point was that with a vacuum pump,, you don't even have to crawl under the car. (except for the filter).

T

 

No problem. Thanks for responding.
Charlie