How did you "BREAK IN" your Prius?

I have built up a number of engines for Vintage racing and there are some common sense things we do.

1. The very first mileage isn't driving the car at all. It is spent parked with the engine idling with the car in Neutral or Park to allow the engine to get to operating temperature. This is the "no load" break-in. Granted, someone else has driven your car first during shipping and delivery but this time is still important. ALL new engines need to seat or wear in somewhat, even your lawnmower! There is nothing special about the ICE that makes it different, it still has pistons, rings and bearings. This can be the time you spend at delivery learning about your car. Just let it warm up.

2. We vary the engine RPM during this warm up (Never over 3000 rpm initially)although that's not as easy with the ICE. Again, just to let things seat.

3. We run the engines as above for about 30 minutes, then we stop the engine and change the oil and filter. No synthetics yet. You would be shocked at what comes out! New engines are always assembled (at the factory or your backyard) using assembly lube. This is a very thick sticky oil to provide lubrication to the engine before the sump oil circulates and it makes assembly easier. It is so good at its job that the engine experiences almost no wear while it is still in the system. This oil change is to get the lube and whatever other crud may be there out of the engine.

4. Then we start to have fun. Racing engines have their own requirements for break-in, mostly dealing with gradually increasing the RPM range up to red line and then keeping them near racing RPM (around 2K less than red line). I can't give you mileages as they don't apply, but you can tell when the engine seems to accelerate more smoothly. By the way, most racing engines fail because of seized bearings, even after all of the above and can often be traced to a piece of grit still in the engine.

I pick up my Prius next week and I will follow this method. I will add "load" to the car by varying speeds and passengers to the car. I'll change the oil and filter (myself or at the dealer) well before 500 miles, especially as it is winter here. If the engine continues to "feel" tight I'll change the oil and filter again. Clean oil is the cheapest insurance you can buy. I won't be "racing" the Prius except past gas stations.

 

I tried to baby it - deal told me not to go above 100km ... but three days after I picked it up, I braked hard and got rear ended. No visable damage, but took it in to the dealership anyway and they confirmed no problems. (Interestingly, the first question they asked was did the display go blank?) Anyway, after that, I just drove it like a normal car, and 2800k later, still working fine.

 

This is a very intersting topic and one that concerns me deeply, as I've recently purchased an '06 prius. I only wish I had read this before I got my car, though. And eventhough it only has 500 miles on the odo, I hate the thought of all those tiny metal fragments circulating in my engine. What I don't understand is this: if breaking-in 80% of the engine can be done in about an hour, why don't auto manufactures do that themselves before final assembly or shipping their cars to dealers? Would it not be better for them to do that rather than to have their engines fail prematurely due to a bad break-in method? Oh well, gotta run now to change the oil and clean the oil pan!

 

Let us know if you find a way to intentionally vary the engine RPMs without hacking into an ECU. Of course the engine will be starting and stopping itself to stay warm and charge the traction battery as needed (though if the car is just sitting without the defrost running it may not need to charge itself).

Also let us know what that factory oil looks like. Betcha a quarter it's plain old 5W-30.

How will you be able to tell if the engine feels tight?

 

I've built engines also and use different assembly lubes depending on the parts. Vasoline, white grease, undiluted STP to name a few. I always run the oil pump without the engine running to prepressurize the oil passages for about 2 minutes. Then, I start the engine and always check oil pressure and listen for abnormalities. I run straight 30 weight oil for initial startup and let it idle while making final ajustments and checks. This usually takes about an hour. Then, I drain and refill with whatever the engine calls for. I do not over rev it or make jack rabbit starts for 500 miles. Then, I drain again and refill and drive it hard, real hard. I usually add 1000 lbs of sand bags or cement to the trunk or bed or pull a 5,000 trailer and drive it up the steepest hill I can find repeatedly until I can get around 15 miles pulling hard to help seal and seat rings. I've never had any trouble with this regime and the engines I've built always seem great for well over 100,000 miles and don't burn excesive oil.
I do not add synthetic oil until the engine is well broken in... say 25,000 miles, more if it's a diesel and I am not a proponent of extended oil changes. I do, however, use oil analysis to provide additional information at the 500 mile mark and check yearly after that with oil anaysis for the optimum oil change interval. I use quality oil and Baldwin filters. I think, but have not substantiated, that Napa filters <Wix> are of Baldwin manufacture. Good filters are very important to engine life and their manufacturing technique for the bypass valve are reasonably good indicators of filter quality. You do'nt want a filter with a piece of bent metal for a bypass valve. Spring valves with seals work well and don't leak oil through the bypass circuit preventing engine wear at start up.
-Paul R. Haller-

 

TO: Tuco, Paul and Richard,

Factory engine assembly areas are remarkably clean places(not many backyards though), I haven't found a bottlecap or wrench inside a new engine yet! The metal bits we are worried about are from the new engine parts wearing in. The OE oil filter will catch most or all of it. Our concern is just not to ask too much of this first filter, oil and assembly lube. The new grit and assembly lube are what we want to get out. Since you can't pre-pressurize your Prius, a quick oil change is the best approach. Everyone has their preferred filters and oil and should stick with those brands that have worked for them in other cars.

At how many miles is more obscure number. Is your initial driving city or highway, dirt roads or pavement, winter or moderate climate? It would pay to think of your mileage more like they do with aircraft and boat engines. It is done in Hours of Operation, not miles. 500 miles could be converted to 10-15 hours of operation (based on average speed). With the Prius ICE 500 could be more like 7-12 hours. My suggestion would be to change the oil as soon as its convenient. The goal is not some time limit, just get the factory oil and crud out.

I am not sure that I can describe the change in feel of the engine wearing in. It is recognizing the difference in sound and feel of the engine when brand new versus after XX miles of driving. The engine starts easier, idles smoother, feels stronger in acceleration. All pretty vague but the clues are there if you pay attention.

My last suggestion may bring some comments but I won't run any engine to the suggested oil change mileages. As above, everyones driving conditions, loads, and weather are different. Modern oil does not breakdown like in days past. Modern filters do a better job dirty than the old filters did new.

My reasons for changing the oil more often is simply modern oils still get dirty from the conditions, even though their ability to lubricate isn't effected. Look at the dipstick in any car, the oil will appear gray to black in color. That color is not the oil breaking down, it's the minute particles of dirt and metal in suspension in the oil. New oil is honey colored, so the farther you oil is from honey the more dirt in suspension. Dirt = friction = engine wear. An oil analysis will tell you exactly what elements are suspended, but besides curiosity, there is nothing you can do about the different elements, other than worry. Changing the oil and filter often is the only thing you have control over.

 

That makes sense. Thanks, Echosys.

Regards,
Tuco.

 

you guys know there's a magnet in the oilpan, right? i haven't read through ALL of the posts but in case noone has mentioned it yet...

in cars today break-in doesn't have to be an exacting process, factory clearances are very tight and you won't see much metal wandering around in the engine compartment.

however, everyone should do what makes them feel happy and good about their car.

 

Just passed the 5000 mile mark on our '05 (6 weeks?) and just drove it normal. Wasn't thinking about all the CVT stuff (which I agree with now that I think of it) and didn't use the Cruise Control for the first 500 miles. No biggie. Took someone else's suggestion and had the Tranny flushed today at the 5000 mile service. All good there B)

 

The break in periods that most manuals mentioned are jsut boilerplate text which ends up in every manual. There is logic to not going out and running LeMans in your new car, but there is also logic in driving it normally and not worrying about what you are doing on the highway or in the city.

If you have a lead foot, temper it. If you don't, don't worry.