First Oil Change...only 2 qts. came out

i just did an oil change yesterday and i got only 2 quarts too! my oil was good and hot and i even tipped the left side of my car to get an extra half quart out. Id like to know if anyone has any ideas too!

additional data: i personally change my oil with full synthetic every 5K miles. ive only just noticed that 2 quarts came out and i don't know if its happened in the past, which now that i think about it, i think it has! i always put in just under 3.4 quarts.

 

You both have a 6 year old car that you have never done an oil change on, and you are wondering why some oil is missing?

Vaporization would be my first guess, but I am not ruling out a slow leak if it has 6 years. With 6 years of use some may have turned to sludge then solidified.

I sure hope I am misunderstanding the 'first oil change' part.

 

How many miles has the car done, and when did you last check the oil level.

John (Britprius)

 

The OP says his dipstick showed oil at the top mark. Mystery deepens...

I think it's got something to do with that tricky pump.

 

Yes I read that bit, but the reading on the dipstick could have been false if he just pulled out the stick and looked at it. On PC there have been numerous posts where people have not checked there oil and wondered why they were getting warning lights on the dash, and even posts reporting the same thing as the OP without dipping the oil before draining.

The thing the OP does not say is how much oil it took to fill up.

John (Britprius)

 

i personally change my oil with full synthetic every 5K miles. ive only just noticed that 2 quarts came out and i don't know if its happened in the past, which now that i think about it, i think it has! i always put in just under 3.4 quarts.

 

There's another half a quart or so in the filter, but you're still missing another full quart there somewhere.

I typically drain about 3 quarts into my catch pan, and the other half quart or so I spill all over myself.

 

I think this is another case of not checking oil level between changes, and only finding the oil is low after draining to discover missing oil.

John (Britprius)

 

sounds like it to me. ive gotta check it more often. the only reason i didn't before was because i would check it and it was fine. i guess things have changes and its lower by 5k miles.

 

What about the engine oil filter, was that replaced? The old oil filter will hold some of the used engine oil.

At least one of the following assertions must be incorrect since the Prius engine oil capacity is spec'd at 3.9 US quarts:

"only 2 quarts came out" What is your means to measure the used engine oil?

"The dip stick read full" Full means that the engine oil level reaches the higher of the two dimples on the dipstick. Was the car on level ground, and the dipstick read after the engine had been off for five minutes or more?

"removing the bolt and nothing came out" Which bolt was removed? If you are referring to the engine oil drain plug, you might want to take a picture with some perspective, to verify you correctly identified and removed that plug.

 

how many miles on your cars?

 

Sucking out only two qts seems about right to me. You won't get whats in the oil filter (as has been mentioned). What I don't follow is the 4th qt that's been mentioned. I've done 20 changes on my 100K+ mile 2005, and only ever re-fill with 3 US Qts. This puts the mark about half way in the dipstick range. 5,000 miles later, its down to the Add mark, and it's time for the next change. For the record, I use a lift and drain from the drain plug. Plus, I change the filter every time.

 

The rated engine oil capacity of the Classic and 2G engine is ~3.9 US quarts. There is around 1.6 quart difference between the two dipstick dimples. Hence the safe operating oil level can be as low as ~2.3 quarts.

If you fill with 3 quarts and drain out 2.3 quarts then your engine has consumed 0.7 quarts over 5K miles. That is pretty good.

However not all engines will consume oil at that rate (some less, others more) and not all owners are diligent about checking engine oil level between oil change intervals. Hence you can think of the 1.6 quart margin over the 2.3 quart minimum as a safety factor.

If you choose to fill with 3 quarts, the safety margin has decreased from 1.6 quarts to 0.7 quarts. Should your engine start burning oil at a faster rate than in the past and you do not promptly check your oil level, then the first warning you will get is when the master warning triangle light turns on as you make a turn, and you are left wondering what is going on.

Eventually you may discover that the engine oil level is too low, but engine damage has probably occurred by then. This results in increasing oil consumption followed eventually by visible exhaust emissions as the oil burn rate increases to an unacceptable level.

 

I can remember one instance of draining around 2 qts in our 2004 G2 Prius. It made me nervous just like OP, and more diligent about checking the oil dipstick level between changes as well as filling to the top dimple when I changed oil. Based on subsequent oil changes no harm was done, since I have not seen increased oil consumption since.

Bottom line: Oil changes every 10k miles is nice, but more frequent checks is a very good idea.

 

Missing Oil Syndrome