Transaxle (or engine) oil change surface exposed unprotected if not driving soon after?

It's not necessary to run the car right away after changing either fluid, except for purposes of making sure that you did the job right and there are no leaks. You might forget to do this check if you let some time elapse. Another household member might jump into the car and zoom off.

 

Yes, I think that you may be obsessing a bit over this. I don't think it makes any measurable difference to the life of the engine whether you start right away or wait till the next day or even a few days later. You will never drain all of the oil (or transaxle fluid) in a normal change, there will always be a thin film of oil on the important surfaces. The only way this would not be the case is if you ran some kind of solvent through the engine to remove the oil film. (Don't do that BTW.)

 

With the Classic and 2G Prius, the oil filter is mounted upright. If you partially fill the new filter with engine oil before installing it, then upon initial startup the engine will run nicely. If you don't fill the oil filter, then upon initial startup the engine will make funny noises for a few seconds until the oil pressure builds up.

 

Thanks Patrick. I've worked with similar systems and know the drill. I always try to fill the filter as much as possible in these cases, though not everyone does this properly (or does it at all). Since you might get a longer delay in oil circulation then start the engine to get the oil system primed and circulating as soon as possible – while warm and the engine friction low. That's all I suggested and I don’t really see why it is so controversial.

 

the engine is not necessarily warm upon restarting after an oil change

i typically allow the motor to drain for quite some time, with the oil fill cap off, dipstick out, filter off and drain plug off, completely depressurizing the system, and allowing for ALL the used oil and residue to drain

the car has cooled 100% by the time the draining is complete

however, when refilling the oil, you are pouring the oil into the head, and it is draining down through the valve train and motor into the pan, and you are essentially manually lubricating from the top end down to the bottom

immediately after refilling the oil, there is probably more oil in the top end and coating the cams/crank as there would be before any start-up

... this manual pre-lubing is another good reason to start-up immediately after the oil change, in addition to checking for leaks/pressure

even if you pre-fill the oil filter, you're not affecting the oil pressure on start up, and pre-filling the filter is not required, nor would it be considered priming

... as you're not priming the oil pump

the circulating oil is coming from the pan, going from the pick-up to the pump and then the circulated through the motor

this is the second virtually identical thread regarding 2009Prius's oil change ... it's looking like more of a hang-up than a lubrication question

 

I advised the OP in the other thread that he'd get better lubrication if he started the engine immediately after the oil change. I don't know why he needed to start another thread to debate it. Several people criticized my suggestion but others (including yourself have confirmed it). You’ve just included one more reason.

Personally I like to do the oil change when the motor is still a bit warm and aren't too concerned about getting every last bit of the old oil out (I warm drain for about 5 minutes with the oil filler cap removed). I know that some folk do like to do it longer and try to get as much of the old out as possible, that’s cool too, but hopefully you can admit that its just as much a "hang-up" as my "cold start the next day without oil system being primed" hangup.

 

i'm not criticizing you :thumb:

when i begin my oil change, the engine is warm
by the time she's topped off and ready to roll, she's cool.

when i check the fluid levels, she's warm again.

i'm addressing the need to prime a Prius

further, even on the old Fords, you didn't need to prime 'em after an oil change, you primed 'em after an engine rebuild :thumb:



2009Prius can start the car or not start the car ... it just doesn't matter

 

Regarding the transaxle fluid change, pls see my post #2 here:
http://priuschat.com/forums/gen-ii-...bleshooting/44124-changing-transaxle-oil.html

 

it's not critical to run a car after a fluid change

if however, you're going to store a car for a long time, areas, including internals, that are not adequately lubricated are subject to oxidation, this includes both hard parts and gaskets, which can dry

example ...
storing a motorcycle, it's better to leave a full tank of "treated" gas than no gas,
to prevent the inside of the gas tank from oxidizing

obviously, because of the elastic polymer bladder, this wouldn't apply to a Prius

but maybe i'm making this more complex

YOU SHOULD RUN THE VEHICLE so that you can ascertain if everything is working properly, sealed properly and pressurized properly

that way, you won't be surprised by a catastrophic failure when you return to the car, and may need to hop in and go

but NO ... you do NOT need to run the car