Diesel Engine Break-In Myth?

[Waldek Walrus]

We've been hearing this one for years and maybe it was partially true at one time but with today's higher tech engine fabbing and tolerances could there be any truth to the old adage that diesel engine fuel economy improves once the engine is "broken-in?"

Why wouldn't a diesel auto manufacturer provide an already broken-in engine for test if it was that easy to get 10 to over 30% improved fuel economy like many suggest?

Back to the OP. My '96 Buick took virtually no break-in as noted. That was par for that period. The '01 Buick took a little bit of break-in, by 5000 miles it was up to full engine performance and has stayed there. I attributed that to slighly tigher tolerances. This has been a sweet running engine for me. The '04 GMC sat on the dealer's lot for six months before I got it for a song. This one took a lot of effort to break it in. The first 3000 miles were touch and go and it took a good 20,000 miles before it acted right to me. I attribute that to sitting on the lot too long not used.

Now we get to the TDI. DBW's break-in instructions have been listed here. Those are probably good for most TDIs. That would not have done it for the one I got. What it took to get my TDI running half way decently was to load the car with people and stuff to a bit over max GVW and go for a week long tear through the mountains. The engine did not want to rev up before that and had no bottom end at all. After 2000 miles of full blast up the mountains with full load it did a lot better, not great but better. Now with 30,000 miles it is still breaking in. I would say break-in with the TDI is no myth. Some of this is the engine management systems learning to work with each other, but a LOT is mechanical wear-in.

Just my $0.02 worth...

 

[mrGutWrench]

(snip) I would say break-in with the TDI is no myth. Some of this is the engine management systems learning to work with each other, but a LOT is mechanical wear-in.
Just my $0.02 worth...

__. I was able to break my '02 in from new (my '03 I bought used with about 110K on it).

After 10K miles, the overall fuel econ average was 50.93
After 20K miles, "" 52.72
After 30K miles, "" 54.47
After 40K miles, "" 55.17
After 50K miles, "" 55.96

__. Of course, that doesn't tell the full story. The "overall" averages are being dragged down by the earlier low mileages. So, another way to look at it:

After 10K miles, the overall fuel econ average was 50.93
From 10K to 20K, the average was 54.61
From 20K to 30K, the average was 58.44
From 30K to 40K, the average was 57.33 (Winter of '04)
From 40K to 50K, the average was 59.12
From 50K to 60K, the average was 55.83 (incl. coast-to-coast trip; hard driving)
From 60K to 70K, the average was 58.51
From 70K to 80K, the average was 57.91 (Winter of '05)

__. All of this was done with EGR set to minimum; at about 50K, the advance in adaptation was reset to approx. maximum at a GTG. All on stock tires, etc.

__. So, with a "pretty much level playing field", my fuel economy went from about 50 MPG to about 59 MPG in 50K miles. How much of this is the driver learning to drive for economy? Well, I was known as the "easy driver" when I was doing miles at Land Rover -- I consistently got the best MPG's of any driver in the fleet. But still, I have the subjective feel that a fair amount of the improvement was me learning to drive a TDI for maximum efficiency. But that can only account for some of the improvement; there must be some amount of "break-in" effect from the car.

__. I agree that the "break-in"effect from the car must be split into engine break-in, drivetrain loosening, tire changes, and computer adaptation. But 50-- 59 MPG is something like a 20% improvement and that's substantial.

 

[TornadoRed]

Facts surrounding TDI engines prior to leaving the factory:

Thus the reason why the initial fill should not be drained before the recommended interval.

 

[dsimmelink]

FIRST oil change mileage???

Just picked up my 09 Jetta tdi sedan on Sunday. My salesman told me the oil should be changed every 10,000 miles and showed me the specific oil I will need for the engine. Of course maintenance is covered through 36,000 miles. So do I indeed want to wait untill 10k for the FIRST oil change or should I do it at 5???

Thanks! =)

 

[TornadoRed]

Just picked up my 09 Jetta tdi sedan on Sunday. My salesman told me the oil should be changed every 10,000 miles and showed me the specific oil I will need for the engine. Of course maintenance is covered through 36,000 miles. So do I indeed want to wait untill 10k for the FIRST oil change or should I do it at 5???

In the previous generations of TDIs, the interval was 5k, 10k, 20k, 30k miles, etc.

I have heard that the 2009 TDIs skip the 5k-mile oil change. Check your owner's manual.

 

[dsimmelink]

In the previous generations of TDIs, the interval was 5k, 10k, 20k, 30k miles, etc.

I have heard that the 2009 TDIs skip the 5k-mile oil change. Check your owner's manual.

Forgot to mention that my next step as soon as I got home from work was to dig into the owner's manual. Thanks for the heads up tho.

 

[Suns_PSD]

I sell 18 wheelers for a living and I often get a phone call complaining about the very poor mpg for the first tank. But w/ every tank it gets better finally topping out around 40-50K miles and staying there for years.

If you forget about the first few tanks (which usually have VERY poor mpg) we still usually see a solid 20% improvement during that time

 

[Squid6290]

And those rules STILL APPLY to the 2009 TDI!

Why doesn't my 2009 owner's manual address any break in procedures other than drive gently and don't exceed 75% of the speedo's top speed for the first 600 miles?

I'm not questioning your recommendations...I'm just curious why VW doesn't provide more detailed guidance for breaking in a TDI.

 

[njkayaker]

Why doesn't my 2009 owner's manual address any break in procedures other than drive gently and don't exceed 75% of the speedo's top speed for the first 600 miles?

I suspect that VW has been giving that same procedures for every TDI. (That is, the procedure VW specifies for the 2009 isn't new.)

 

[Rod Bearing]

Well I just unloaded my 06 TDI off the trailer, complete with it's new engine and transmission.

I broke the first one in per the granny routine. I'm going to do the opposite on this one. I'll drive it like I'm mad at it.

They tell me the DMF on this one is updated. I'm going to drain the oil tonight, and change the filter, then it's in with some Mobil 1 ESP 5w30 507.00.

This one seems to run a lot better already. It's good to have it back. I'm leaving Friday for Fargo in it. It's gonna get a whuppin.

 

[JonFord]

Well put your armor on. You will get a beating. As you can read, I support you, so keep the boost up.

Now I am popping the pop corn and selling beer. More fun when they are a little bit tippsy.


JonFord

 

[MrSprdSheet]

1,000-10,000 miles
Use the full 5,100 rpm power range.
...
And those rules STILL APPLY to the 2009 TDI!
...
No VW engine should EVER be run above 75% of maximum rpm in the first 1,000 miles...EVER! Load is a new engines friend, running up a mountain in 5th gear while varying rpms = The best thing you can do to a new engine. Driving around screaming the engine in 1st gear and low load = the worst thing you can do to a new TDI.
DB

Drivbiwire,

Do you know the '09s redline at 4,500 RPM? Up to 3,800 is about 85% of that. So, a little lower max maybe?

I'm not too proud to admit I left the DSG in Tip mode and had the car shift before the idiot behind the wheel woke up a couple times on the delivery ride home. At least it was brief.

I, for one, hope JohnFord sticks around. If someone doesn't question doctrine, something else changes that no one catches. I'm new to diesels, but worked on a few Porsches and went through a re-ring process of my own.

-Do rings even stay in one spot to wear in?
-Has anyone indexed them to know for sure they aren't rotating during their life?
-Is it deposits from initial blow by that actually thicken cyclinder walls, what?, a thousandth of an inch, or so, or enough to seal any bore/taper irregularities? What specifically is breaking in? Rings, pistons??
-The guy who did my paper work for the new TDI was talkin' all kindz
'a crazy stuff, like 25:1 compression ratios, chrome rings and runaway diesels . I was thinkin' Man, have I entered a new paradigm 'er what?

I remember looking at the unique cross-hatch on the nikasil lined pistons I was using after they had 60,000 miles on them. They could have been new (for 95% of the stroke, anyway) and the theory was if any ring seating had taken place, it was in the first revolutions of the engine, not 1,000, or more miles. Castrol for the first 5k, etc, etc.

My head is filled with more that is probably doing me a disservice with the TDI than otherwise, but I still gotta ask.

 

[TornadoRed]

Do you know the '09s redline at 4,500 RPM? Up to 3,800 is about 85% of that. So, a little lower max maybe?

The "hard" redline is, or should be, 5100 rpm. So 75% of that is around 3800 rpm.

 

[Drivbiwire]

Drivbiwire,

Do you know the '09s redline at 4,500 RPM? Up to 3,800 is about 85% of that. So, a little lower max maybe?

Start the car and push the pedal to the floor and keep it there, the engine will smoothly rev and stop at 5100 rpm (+/- 100).

4500 is the start of the "cautionary" range (despite being marked in red) and the rev limit is 5100.

-Do rings even stay in one spot to wear in?
-Has anyone indexed them to know for sure they aren't rotating during their life?

Yes rings in a TDI remain fixed. They are set at 120 degree offsets and will remain at that offset for the life of the motor.

-Is it deposits from initial blow by that actually thicken cyclinder walls, what?, a thousandth of an inch, or so, or enough to seal any bore/taper irregularities?

No deposits on the cylinders (at all). The accuracy is down to 100,000th of an inch (.00001) in and measured in micron accuracy. Any accumulation would ruin the compression due to the high compression ratios and accuracy required to achieve those pressures.

What specifically is breaking in? Rings, pistons??

Rings. High compression ring profiles (diesel) have profiles that rely on the high cylinder pressures to exert outward force on the rings to seal against the cylinders. In addition the rings must account for the increase in pressures under combustion. At low loads the rings are applying very little force against the cylinder walls. As load and "BMEP" rise, the rings force themselves against the cylinders with increasing force sufficient to seal in combustion gasses. The idea is to wear in the rings at a rate that results in the most uniform alignment of the ring to cylinder surfaces. Too fast or too slow can cause poor sealing for the life of the motor. TDI engines have an optimal load range of around 80% of rated power without reducing engine life translated "about" 80-100mph driving down the highway.

-The guy who did my paper work for the new TDI was talkin' all kindz
'a crazy stuff, like 25:1 compression ratios

16.5:1

chrome rings

True, the top compression ring is in fact chrome sealing against cast iron cylinders.

and runaway diesels .

True, if the turbo compressor seal fails you can have a runaway (it has happened). To stop a runaway simply shut the ignition off. VW incorporates an emergency shut-off which also doubles as the anti-shudder valve. The system closes a valve that stops incoming air and the motor shuts down...just don't attempt to restart it!

I was thinkin' Man, have I entered a new paradigm 'er what?

Welcome to the "Diesel-Cycle"

I remember looking at the unique cross-hatch on the nikasil lined pistons I was using after they had 60,000 miles on them. They could have been new (for 95% of the stroke, anyway) and the theory was if any ring seating had taken place, it was in the first revolutions of the engine, not 1,000, or more miles. Castrol for the first 5k, etc, etc.

I have had 400,000 mile TDI engines apart (head gasket) and there is NO ridge yet formed at the top of the cylinder. All original cross-hatch marks are STILL clearly visible! I told the owner, check back at 1,000,000 miles and maybe we might have some indication of wear.

My head is filled with more that is probably doing me a disservice with the TDI than otherwise, but I still gotta ask.

Best advice, follow the service manual TO THE "T". Don't get creative, don't over-service and don't baby these cars. These are pure bred Autobahn oil burners with extreme duty industrial lineage in their veins.

By the book, drive more and worry less.

DB

 

[BlueMotion]

I, for one, hope JohnFord sticks around. If someone doesn't question doctrine, something else changes that no one catches. I'm new to diesels...

Maybe he'll pick up the tab when the camshaft starts to wear out prematurely or the DPF only lasts 30,000 miles and VW won't repair it under warranty because the oil wasn't what they specified.

 

[DoctorDawg]

To stop a runaway simply shut the ignition off. VW incorporates an emergency shut-off which also doubles as the anti-shudder valve. The system closes a valve that stops incoming air and the motor shuts down

I'm so pleased to learn that somebody finally figgered this out...thanks, DBW! In my old beater Dodge Cummins conventional wisdom has it that no force on earth can stop a diesel runaway; the usual advice is "run like hell!" I've been drivin' around in it for the last 100K with a (nowadays-not-particularly-legal) freon fire extinguisher, ready to unload it into the air intake in case of runaway, while secretly wondering if I (or anyone else) would have the spheroids to face half a ton of screaming runaway Cummins long enough to get the job done. I like "simply shut the ignition off" a LOT better.

 

[TornadoRed]

I have heard that the anti-shudder valve will reopen in 0.5-1.0 seconds -- so it is not a sure-fire method of stopping a runaway TDI engine. Better than nothing, I suppose.

I wonder if I would have the presence of mind to 1) shut off the engine, and 2) leave it in gear and stomp on the brakes.

 

[DoctorDawg]

I have heard that the anti-shudder valve will reopen in 0.5-1.0 seconds -- so it is not a sure-fire method of stopping a runaway TDI engine.

Hmm...mebbe I better buy myself another freon fire extinguisher....

If anyone cares, you can still find 'em on ebay.

There are a number of after-market vendors for manually activated anti-runaway valves for big rigs and construction equipment (they're required by law in gas and oil fields in some parts). These are typically built to standards more typically seen with the hatches of nuclear missile silos...'beefy' doesn't even begin to describe it...because once that valve slams shut the still-screaming turbo will instantly suck a huge vaccuum against it, conditions under which a flimsy valve would simply implode. This is prolly more of a concern with heavy engines and big turbos, like my Cummins, but I wonder if the anti-shudder valve is intentionally designed to bear the load a runaway TDI's turbo can produce? And is the anti-shudder valve immediately upstream of the turbo? If there's a plastic hose between valve and turbo then a runaway might simply inhale the hose and keep a-screamin'.... I dunno....

It occurs to me that there's prolly a diesel newbie out there sommers scratching his head and wondering what the h*ll we're talking about, so here it is: 'diesel runaway' occurs when the seals on your turbo fail, allowing engine oil into your turbo. Now, instead of merely supplying your engine with air under pressure, your turbo is suddenly supplying your engine with an air/fuel mixture under pressure, causing your engine to run faster. This, in turn, causes your turbo to run faster, feeding even more air/fuel mixture to your engine, which causes your engine to run even faster, and...well, you see where I'm going with this. If unchecked, your engine soon disassembles itself into its component sub-atomic particles, rather catastrophically. Is this something to lay awake nights worrying about? No. Your chances of dying in an auto accident are astronomically higher than your chances of ever witnessing a diesel runaway (much less even living in the same zip code as one). Its mostly something that diesel jocks love to talk about...I mean, how cool is 'spontaneous explosive engine self-destruction preceded by rapidly escalating screaming loud noise'? Ya gotta love it.

And why a freon fire extinguisher, I hear you ask? Well, conventional wisdom has it that a standard bicarbonate powder fire extinguisher will simply gum up yer air filter, causing your runaway turbo to inhale said filter, chuckle maliciously, and keep on goin, whereas freon (being a gas) will pass through the filter unimpeded, suffocating the fires of hell in your runaway engine. I have no idea whether this is nonsense or not, but it sounds plausible enough to me.

Bottom line, there are enough uncertainties involved in diesel runaway that, should you ever be unlucky enough to have one happening under your hood, the best advice is prolly "simply turn the key off and then run like hell!" [n.b.: my attorney has asked me to add, "but be sure to look both ways before running out into the street!"]

 

[MrSprdSheet]

I think part of the lore to runaway diesels stems from when they ran much hihger than 16:1 compression ratios. I take it somewhere higher than this (20-30 to 1?) is where compressed air, even without fuel, becomes a greater problem. What ratio does the Dodge run?

 

[BlueMotion]

I think part of the lore to runaway diesels stems from when they ran much hihger than 16:1 compression ratios. I take it somewhere higher than this (20-30 to 1?) is where compressed air, even without fuel, becomes a greater problem. What ratio does the Dodge run?

It's not CR that causes them to run away, it's putting fuel in. I've worked on Volkswagens for years and only ever known of one that ran away. The owner over filled it with oil and the oil came up through the breather into the air box, and got into the inlet that way. Since it was not getting in through the fuel system there was no way to shut it down with the key. It was impossible to stall and just slipped the clutch.

 

[40X40]

I think part of the lore to runaway diesels stems from when they ran much hihger than 16:1 compression ratios. I take it somewhere higher than this (20-30 to 1?) is where compressed air, even without fuel, becomes a greater problem. What ratio does the Dodge run?

Uhh, WHAT? Please don't post speculation without some kind of link. Some poor ignorant kid may find your post sometime in the future and think it is factual.

You must have A FUEL for combustion to take place.

The fuel can be unusual: Natural gas leaking from a pipeline, Engine oil from the crankcase, Propane leaking from a nearby tank, etc. But NEVER air by itself.

You can stop a diesel by shutting off either the AIR or the FUEL.

Bill

 

[MrSprdSheet]

You must have A FUEL for combustion to take place.

Bill

I lost my mind for a moment and thought oxygen became volatile under high compression. I'm learning/re-learning about some fundamental stuff and its been a while.

 

[Smokerr]

It's really obvious on the old 2 stroke Detroits I work on. Those things sound like there ain't any rings in them right after an overhaul. They start hard, lots of smokey cranking, idle like there's a couple pistons missing, the airboxes drool oil out the drain tubes, they smoke like a wood stove, and have no throttle response. After a good hour long dyno pull routine, they quit slobbering oil, stop smoking, get that really snappy quick throttle response they're known for, and get a really nice smooth idle clatter to them. Thats all due to the piston rings and valves seating and sealing off. M

Lets hear it for the old 2 Cycle Detroit Diesels!. Sad to see them go. They always ran a lot cleaner (if timing was set right) that the Cats and Cummins.

I have 6 of the 6V71 engines on fire pumps, and they should last in that service unt8il the building falls down. Terrific choice for that nasty application (no reasonable way to start a fire pump unloaded, so they go from zero to 2200 all the while the drag of the impeller is loading it up)

 

[KnLPrez]

I do not have a scanner, otherwise I could post some really informative pictures, but here is the little bit that I know about "breaking in" anything that has moving surfaces in contact, from a materials scientist's point of view.

Wear occurs when two moving surfaces are in contact, be it sliding (piston rings on cylinder bore), rotational (ball bearings around a journal) or a combination of both. When a surface wears it produces wear particles. The atomic surface of two moving objects in contact reaches extremely high temperatures. These very high temperatures cause changes in the wear particles. What happens is that over time a layer of a new material forms on the surfaces that are in contact, called the friction layer. The friction layer is of a completely new material not present in either surface in contact. This layer is very thin, usually measured in microns. This friction layer can be viewed with a section of a wear surface under an electron microscope. As this friction layer builds up, wear decreases. Total wear of a part and time in contact are related logarithmically, meaning that as time goes on the total amount of wear levels off. This effectively means that at a certain time frictional forces no longer cause any noticeable wear in the components.

This is the reason that a motor can last for hundreds of thousands of miles. To think about how much contact a piston undergoes with the cylinder wall, you need to take the stroke of the engine x average rpm during the life of the engine x 2 (each revolution the piston travels the distance of the stroke up, then down) x 60 min/hour x hours used. For an engine with a 4" stroke, operating at an average of 1500 rpm, the total distance the piston slides against the cylinder wall is 720,000 inches per hour of use! This is equal to dragging the piston over 11 miles across the cylinder wall ever hour! It has always fascinated me that a motor lasts even 100 miles!

Knowing this, it seems to me that from a materials point of view, the quicker a friction layer can be established the better, however the loads should be as low as possible while the layer is forming. For a piston ring in contact with a cylinder wall, the forces are probably fairly constant; varying only with changing side loads on the piston and the expansion and contraction of the materials as the temperature changes.

There is a lot more going on within a vehicle besides what is happening at the microscopic level on surfaces in contact. I am not an expert, but I have studied the subject and thought that this would help shed some light on break-in periods.

I will try to find some pictures of friction layers from brake pads and rotors, or find a scanner so I can upload some, as it is pretty cool.

I hope that was readable... it is kinda late

Kingston

 

[BlueMotion]

they smoke like a wood stove,

You're obviously stuck in a timewarp where diesels and woodstoves still smoke.

 

[Drivbiwire]

I have heard that the anti-shudder valve will reopen in 0.5-1.0 seconds -- so it is not a sure-fire method of stopping a runaway TDI engine. Better than nothing, I suppose.

I wonder if I would have the presence of mind to 1) shut off the engine, and 2) leave it in gear and stomp on the brakes.

It re-opens 5 seconds after crank rotation completely stops.

Vacuum to hold the valve closed after the engine comes to a stop is provided by the vacuum reservoir mounted on the engine (black ball) near the oil filter housing.

DB

DB

 

[TornadoRed]

It re-opens 5 seconds after crank rotation completely stops.

Vacuum to hold the valve closed after the engine comes to a stop is provided by the vacuum reservoir mounted on the engine (black ball) near the oil filter housing.

Okay, good to know.

I guess some people can hear the anti-shudder valve reopening, but I never have.

 

[OsirisTDI]

That's what that THUD is all about...so, it's a good sound. For 16 months, I'd say to myself, that can't be a bad sound.

 

[Thunderstruck]

DBW-You're saying in the break in procedures "Frequent firm application of power is strongly recommended up to 3,800 rpm" but then it says "No VW engine should EVER be run above 75% of maximum rpm in the first 1,000 miles...EVER!". max rpm on my new 09 is 4400, so I ran it to around 3800 tonight. 75% of 4400 is 3300, not 3800. Hope I didn't hose it w/o realizing it.

 

[TornadoRed]

http://forums.tdiclub.com/showpost.php?p=2271224&postcount=43