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Discussion Starter · #1 ·
I did a search through the forums for this topic, but I didn't find anything on this other than not to do it.

I started driving my tc from mile 0 to to about 700 without looking at the break-in procedure. I didn't brake abruptly or accelerate hard or race the engine, but one thing I did every now and then was drive at a constant speed a couple of times for about 15 minutes on the freeway. What are the adverse consequences of doing this to the engine?

Another question I have is should I get an oil change immediately after the break-in period? I know that with motorcycles, we get an oil change after the break-in to get all the metal bits and other crap out of the oil. Is this the same with the tc too?
 

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It's not necessary. We've had a lot of discussions about break-in procedure and there are two camps. Factory and other. You didn't do any harm with what you did. The factory just doesn't want you going on a long trip and setting the cruise control for a few hours during the break-in period. I say that's all a bunch of crap anyway, but you didn't hurt a thing.
 

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Any idea what Toyota's reasoning could be for the break-in rules? (As in why exactly wouldn't you want to set cruise control on a new engine?)
 

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Originally posted by Pharoh@Dec 18 2005, 10:35 AM
Any idea what Toyota's reasoning could be for the break-in rules? (As in why exactly wouldn't you want to set cruise control on a new engine?)
The pistons need a varying thermal load to size themselves properly. Setting the cruise control just about ensures a fairly constant thermal load since most people don't climb hills with their cruise on (I do, but I'm weird anyway). The point of break-in is to set the crystalline structure of the aluminum the piston is made of. In service, under heavy load, the aluminum approaches a plastic state from heat. As it does this, the metal's grain changes, and as it cools back from plastic, it realigns itself. When it does this if the shock is too sudden or too slow the piston may resize itself in a bad way. This is the basis of the break-in that Motoman and I both recommend. Predictably increasing thermal load over a specific (short) time period until break-in is complete.

"Taking it easy" (factory break-in) does not promote this, and only makes a muck out of a good engine IMHO. As I said before, the last time I did a factory break-in I got an engine that burned a quart of oil every 3000 miles. I'll never do that again.
 

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Originally posted by coffeegrinds@Dec 18 2005, 10:35 AM
Thanks for the help.

Do you recommend getting the oil changed after the break-in period to get rid of whatever metal shavings and debris are in the oil?
No. It's a waste of good oil. If this really meant anything, you'd drop the oil pan and clean the screen on the oil intake. No manufacturer recommends this because they don't want to pay for it, and the long term results indicate there is no advantage to it if your factory is assembling clean engines (as they very well should be).

I have done this with racing engines on motorcycles, but not cars.
 

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Discussion Starter · #8 ·
Alright, I think I'll try to save money and one of my three free oil changes, and hold off after the break-in period. Thanks for the input. I'm used to motorcycles as well, and the amount of metal debris we see after the break-in can get excessive.

Another question I have is frequency of oil changes. I know the manual says every 5000 miles, but if I'm a daily commuter that doesn't go very far from home, won't that build up sludge? And shouldn't I get oil change every 3000 miles at that point or am I being too cautious?
 

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Lance, aren't you contradicting yourself when you say not to change oil after break in period?

As part of the break in procedure motoman suggested that you change oil the first 20 miles.

Do you have any comments on that or was motoman referring to motorcycles?


Edit: Not really contradicting, but I just want to know.
 

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On an engine I've just built for a bike, yeah, I change the oil right away. I also use conventional oil for break-in, and I wouldn't run it for any length of time anyway. I also drop the oil pan and clean the screen on the oil pick up on a bike engine, but I don't on a car because getting the oil pan off a car is not a simple task, even if you appear to have full access to it from below. The FIPG they use to seal the oil pan is no fun to split.

Added to this, you get your car from Toyco with oil in it. It's already been driven by who knows whom a few times. It was also assembled in a climate controlled environment, maybe not a class 100 clean room but certainly class 1000. There isn't going to be much in the oil pan or the screen. Doing it at home is a lot different.

AFA bikes, it seems Kawasaki throws a handful of crap in their engines. I don't know why, but we always called it the Kawasaki swarth. Brand new, straight from the factory, crap in the oil pan every single time on first tear down. Yamaha, Suzuki, and Honda don't have this issue.

The other big deal about bikes is they almost all have wet clutches. Debris from the clutch friction material is one of the biggest pollutants in the oil on all bikes, and because the oil runs through a constant mesh gearbox and wet clutch, it is infinitely more abused than any car engine.

Last but not least, if you are doing frequent short drives (less than 10 minutes operating time) you need to change your oil much more frequently, and yes, 3000 miles would not be a bad choice if you are using conventional oil, and I would venture to say even I wouldn't run more than 5k on synthetic if I did a lot of less than 5 mile trips.

The key is this: water condenses inside the engine when you start it up. It's a simple fact of adding heat to the air. The water condenses on the sides of the block and runs down on top of the oil. On its way, it washes off byproducts of combustion, including highly corrosive acids from impurities in the fuel (like sulfur). Because the oil is cold, the water sits on top and sloshes around, but doesn't enter the oiling system.

Once the engine gets up to operating temperature, the oil sump will be somewhere between 180F and 200F, possibly more depending on conditions, but ideal oil temperature is 180F. This is enough to cause the water on top of the oil to vaporize, purge the oil of the impurities the water carried, and get pulled through the engine's PCV system, burned in the combustion chamber and run through the catalytic converters to clean up the bad stuff.

If the engine doesn't get hot and the water doesn't vaporize, it sits on top of the oil waiting for the next cold cycle to add more water and contaminants to the oil and eventually form sludge out of perfectly good oil. This is why more frequent oil changes are necessary for people who typically make short trips. It's actually better for the engine to run for at least 20 minutes every time you start the engine. It just doesn't make sense all the time for other reasons.
 

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i gave the short version of that to my brother, who is prone to short drives in his tacoma now that he moved closer to his employer.
 

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Discussion Starter · #14 ·
Looks like I'll be getting standard oil changes then. The service manual has certain things to do at 5000 mile intervals like the tire rotation. Can I get away with doing stuff like that at 6000 mile intervals (i.e. every other oil change?)?
 

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Just keep an eye on your tire wear and rotate them as necessary. It's a cost saving thing, not necessarily a life saving one.
 

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Discussion Starter · #16 ·
Thanks for the help.

One other question I have is I'm sure Toyota/Scion figures most of the people that buy the tc are average commuter/drivers like myself, so why would they put the service intervals at 5000 miles if they know it'd be better for the engine to do it every 3000?
 

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The average commuter drives more than 20 minutes each way these days. They used to have a 7500 mile interval, but had too many issues with sludge, so they reduced it to 5k to catch the vast majority of drivers. There are still a few who don't drive more than 10 minutes, but they are statistically insignificant now. If a trend develops where fewer drivers are driving 20 minutes or more, we may see another shift to shorter change intervals, or we'll see the Mercedes style change interval where the ECM keeps track of the type of driving you do and sets an oil change light on the dash to tell you when it is time to change your oil. That would probably be most cost effective since it's just a software change, but Toyco hasn't adopted that approach yet.
 

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Hmm... I work about 4 mins from my house four days a week. I come home on breaks. I drive to school 40 mins twice a week. I knew frequent short trips are bad foe the engine but I didnt know you could prevent the damage it could cause. I think I ought to take advantage of those free oil changes a bit sooner than 3000k. Thanks for the good info.
 
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