Rising Oil Level

[ryogajyc]

I've measured the oil level several times since I've gotten my Prius. Right after I had taken delivery of it, I noted it was well within the min/max marks. After the first 1000 miles, I checked again and it was quite a bit above the max mark! It is consistently above the max mark now. I've been meaning to drain a bit of oil out to fix this, since this is definitely out of spec. Unfortunately, I've been really busy lately, but hopefully I can get to it tonight or tomorrow.

Also, I think the first time I checked it, the engine was cold. All the subsequent checks were when the engine was hot. I'm not sure if that makes a difference. Has anyone had something similar happen? It's seems very odd to me.

[toolbox]

the temp of the engine will make a small difference in the level of oil recorded on you dipstick. oil from the top of the engine has to have time to return to the oilpan but it shouldnt cause it to go over max full (thats why they give you a small full range on the stick to allow for a small amount of oil consuption and engine temp). once the level reaches past max full the oil begins to contact the bottom of the crankshaft which intoduces air into the oil which is bad plus puts a load on the crank. i would be more worried about the possiblity of a head gsk or cylinder wall leaking coolant into oil. which could also give you the same syptoms you descibe. watch for condensation in you oil fill cap and also oil looking milky. it you notice it over full drain a small quanity when the engine is cold and make sure to have the veh off the jack when checking the level and check very frequently or get to dealer with that low of mileage. the prius only holds about 4 quarts not 5 as most cars do.

[DaveinOlyWA]

i think the Prius only has 3.5 quarts... also i was under the impression that the oil measures low in a cold engine.

[toolbox]

its 3.9 is what toyota recomends to be exact. i changed my oil to mobile one @ 1k and used a toyota replacement oil filter. i used a 5 gallon jug of mobile1 5w30 and it took right about four quarts but its hard to measure out what i used on a five gallon jug so thats why i put about four. i drained the engine for awhile till no trickle but primed the oil filter before install. oil level is highest cold all circulated oil will drain back to the pan and this will cause the level to rise. if you dont believe me change your oil and fill it to a desired level. run the engine and your level will decrease, come back an hour later and you will right back where it was. oil will trickle forever

[DaveinOlyWA]

i did try it... there is no difference that i can see from sitting overnight and from taking a one way 55 mile trip on the freeway and checking it.

[toolbox]

its only a very small amount and how soon after did you check because the cleaner the engine faster the oil will return. i overfilled mine a tad during its first oil change but it registered right below full on the stick after start up (i let it cycle once after key on). i came out the next day and it was overfull. i assumed it was just drainback from me checking with oil with it still captured in the cylinder head. i spoke with a service writer at a dealer last week he told me keep the oil changed about every 3k running mineral oil because the prius engines are developing condesation in the oil because they cycle on/off. thats why i run syth it has better protection and higher detergents but with his mileage i wouldnt think he would have condensation yet.

[Ray Moore]

The same thing happens to mine. I only use 3.5 quarts now so there is room for the absorption of water. I use mobil1 now and I'm not sure that it is absorbing as much water as before. I drained the extra with a thin vinyl tubing down the dipstick tube into a dasani bottle. It took 30 minutes while I sat and read. There was no mess and the full 16.9 oz. bottle got it back under the full line. I no longer put in more than 3.5 quarts.

[DaveinOlyWA]

i checked it within a minute of shutting of the car.

to be honest with ya, i have to check it several times as it is very difficult to tell where the level is as the oil was just changed.

[toolbox]

lol... you had me curious so i just checked my own car. i changed my oil about 1500 miles ago and cold (sat all night) the oil is still measuring right under full cold (make sure you double wipe the dipstick first reading is never accurate). i cycled the car on and put it in gear with foot on the brake and let in run prob a good 30 seconds and rechecked it right after it shut down (first check showed right underfull thats why you have to check twice) and second check showed the oil level had dropped about a half inch on the stick. my car hot the oil level drops a small bit.

running the engine will splash oil onto the dipstick and pulling it up the tube will have oil coats the walls of the tube that is why you have to double check wiping off the stick