Engine oil replacement?

In looking at my Tundra manual the instructions are clear: keep the level between the marks on the dipsticks and it gives an "approximate" (their word) range between the marks. It never says to fill with X quarts. It doesn't have instructions for changing oil...apparently Toyota doesn't consider that a DIY item. It does however list the oil capacity.

I've always targeted midway between the marks. I've never had any internal motor problems with any vehicle I bought new.

 

dogfriend,

Thanks for that pdf. Note that the header is "Capacity." This is being misinterpreted by the mechanics as refill volume. Instead it will put them at capacity: the full mark. Anecdotal evidence/measurment here suggests the 3.9 liters is still ~0.2 liters too much in real world oil changes.

The "dry fill" was particularly helpful, 4.3 quarts, because it illustrates that 0.4 quarts are retained in various spaces (when level) with no filter.

It looks like this came out of the dealer service manual.

 

The advantage to being near the top mark is to have 'enough' on board in case the car leaks or burns oil between your oil-level checks. Both conditions appear to be very rare in Prius.

Two possible advantages to being not too close to the bottom mark are more oil for heat transfer, and avoiding pump starvation during high-G maneuvers. The latter are also rare in Prius

There is no known advantage to being above the top mark, and a couple of potential disadvantages.

 

For the last three decades, every time I mention this someone gets upset - but it's usually the same person who believes passionately that using high octane fuel is "better for the car" regardless of manufacturer specification. Well, here goes:

In the 1970s, the military did an evaluation comparing common SAE-rated organic oil to Mobil 1 on some thousand of vehicles, gasoline and diesel, of which many were subject to very hard usage. All other factors (oil change intervals, filters, etc.) were kept equal, and the sheer number of vehicles in each group ensured statistically valid results. At the end, the records for the test groups showed there was no difference in maintenance. Randomly selected vehicles were torn down at 100k miles, and there was no differences in engine wear - measured with micrometers and microscopes - and no differences in accumulations of residue or sludge. There was, however, a third group, the vehicles of which used recycled oil (filtered and with replaced additives) - it fared badly.

Interestingly, despite the hard evidence in front of us, car nuts like me continued to use Mobil 1 in our cars. We also filled our cooling systems with 100% coolant - despite temperate weather. However, there was never an issue about octane - at that time, I had no choice but to use 96 in my Porsche, with manual ignition timing control to permit squeezing the last hp out of it.

The bottom line: synthetic oil, special coolant protocols, and high octane fuel will not make your Prius last longer. Neither will a $300 "Teflon paint treatment" or magnets on the fuel lines. Any combination of these may make you feel that you're repaying the car for the satisfaction it gives you, but it's a waste of money. Really.

The Prius ICE should easily last 300,000 miles without overhaul, because when accelerating from zero the electric motor does the hard work. That relieves the ICE of the high BMEP (Brake Mean Effective Pressure) conditions that produce the most wear and generate the biggest temperature differentials between internal locations. Have you noticed how cool your Prius ICE is to the touch?

If you really want to do something nice for your car, take the tire pressure down from 45# to that specified in the manual. That will allow the tires to absorb more of the road-rubber energy, and reduce the average vibration-induced G-shock applied to suspension components in the lower quadrature flanton. And you can quote me...

 

I'm just going to quote this part. I'm going to try to work this phrase into my next conversation at work and see if anyone calls me on it. :evil:

 

Eisenson,

I agree that modern engines are likely to last a very long time if basic maintenance is done. Synthetic is likely overkill for 99% of us. I don't expect much difference in dino oil and synthetic when the oil change intervals are short (the dino oil specified intervals). I also don't expect much on regularly driven vehicles or mild environments.

However, from what I've seen the synthetic does a better job of keeping parts wetted when the vehicle is not operated for longer periods. I've also seen a day cold enough (local all time record) that dino oil stuck to the dipstick like molasses and I had considerable engine wear as a result of trying to start that car that day (necessity, unfortunately--that old car never ran as well again.) When I drain dino oil at 5K it looks much worse than synthetic at 7.5k. The synthetic is more robust, but it is not a must. (I didn't start using it until I began squeezing every ounce of performance out of my Nissan, with a lot of time spent near redline with quite a bit more power than it was originally built to produce.)

Other than price the most annoying think about running synthetic is trying to read the dipstick.

Whether or not someone uses synthetic or dino oil doesn't matter much to me if they maintain their vehicle.

 

The last time I was in I asked for 3.5, and my dipstick (after several hours of rest) was every bit up to the full line on the dipstick

 

Then what you asked for was not what you got!

 

I took my Prius in today for my first, dealer-paid oil change. I have always done my own oil changes in the past because of the risks mentioned here of having someone else do it, but I thought I would give it a try this time. I got home and let the car set for about an hour before checking the oil level. Guess what? The level was 5/8" above the Full mark. I drained the oil down to the Full mark. I poured the drained oil into a container that had oz and ml increments marked on it. I measured just a little over 14 oz. There was a very small amount left in the drain pan, so I may have taken about 15 oz out.
I am going to call my dealer tomorrow to discuss this with whomever needs to know. I want to be prepared for the answer... "A little bit over is not going to hurt anything." Is there some documentation, other than the Toyota Owner's Manual (which only says not to overfill), that I can refer to in my talk with the dealer about this? I would like to have some documented facts about what harm overfilling might cause.

 

There is a TSB on it.

 

dogfriend,

Thanks for sharing that TSB! It is clear why the dealers are going to screw up every oil change. Toyota is telling them to overfill the oil so that it will always be overfull after a change. WTH is Toyota thinking? This isn't rocket science. Unless they intend for the "full" market to actually be the ADD OIL mark, this is an idiotic TSB.

 

Here is some pretty good info on just about everything you wanted to know about engine oil.