[hanstj]

Hi all,

I have recently read through the article on proper break-in procedure here http://www.myturbodiesel.com/1000q/enginebreakin.htm.

There is something I would like to clarify though.

Under the sub-topic "Proper new engine break in procedure (can really apply to any modern water cooled passenger car engine)", the writer mentioned this term "% power or throttle" several times.

For example,

On a brand new engine (rebuilt or replaced engine), let it idle for 20 seconds to let the oil circulate. You should also be checking coolant levels and other things on a new engine. Then drive it with normal load below about 50-60% power until the engine is warm.

After you've put some miles on it, once the engine is warm, rev it at varying throttle up to 75% with both medium load while driving in stop and go conditions. You want to avoid low rpm/high load power settings (like lugging the engine) so don't be afraid to downshift. Do not go to redline, try to avoid going above 80% power, and avoid steady rpm driving (like highway) and excessive idling. The best thing you can do is to drive up to 75% power and then coast down in gear under engine braking (foot completely off the accelerator pedal).

Between about 500-1000 miles, drive more normally and try to not exceed 80% throttle/load. A brief, smooth, rpm cycling to 95% power is fine after 1000 miles.

For all the above phrase in bold, what does it refer to actually? Does it refer to the rpm (i.e., 75% power means 75% of the redline rpm)?

OR

Does it refer to how you press the accelerator pedal (i.e., 100% power or throttle means you totally floor the accelerator pedal)?

 

[hanstj]

Thank you very much. I think it is much clearer now.

By the way, I also found this thread about the same topic of breaking-in: http://forums.tdiclub.com/showpost.php?p=2264550&postcount=28

I think, this post is more or less the same as yours. What do you think about that post? Do you think that is a good breaking-in procedure?

 

[hanstj]

Yes, they pretty much say the same thing. A little more or a little less isn't as important as long term maintenance on the long term health of the engine. Letting a 3 year old have a soda won't contribute to obesity but giving them 2 liters of soda every day for life will.

The difference is that I am not so strict about exact RPM for the reasons stated above. RPM is only a partial indicator of what's happening - load is also important and rpm and load depend on the situation. As a general rule during break in, medium rpm with higher load is better than higher rpm with low load since this loads the rings and engine without overloading them.

And automatic transmissions can't control the engine rpm and load as easily as a manual transmission - does this mean that all autos are broken in incorrectly?

This is another thread talking about break-in procedure: http://forums.tdiclub.com/showthread.php?p=464223. It is a very long thread (49 pages). Here and there, people did ask the break-in procedure for automatic transmission.

For automatic transmission, I think Drivbiwire (the person who wrote the other break-in procedure) suggested to just drive it with varying load without having to worry too much on the RPM. Since it is pretty difficult to upshift or downshift at a specific rpm in automatic, except maybe tiptronic.

 

[hanstj]

What do you mean by "it doesn't make a big difference"?

From what I have understood, the most important thing to do in breaking-in an engine is to vary the load on the engine. In other words, babying the engine (most probably with an intention to get better mileage) is a BIG NO. In fact, a properly broken-in engine will potentially achieve better mileage than if you just baby it from the beginning.

All those info are based on what I have been reading these past few days. I have never practiced the procedure myself since I don't even own a TDI. So, I am basically trying to gather as much knowledge as possible before I actually drive my own TDI.