jhcicco

I read on the Diesel forum that the following is a good way to break-in the 320 engine. Has anyone tried/is trying this method? Or are there other ways? When I had my diesel BMW, I babied it for about 2K miles and certainly didn't follow this method; it lasted 309K miles.

Break-in routine for Jeeps with Mercedes-Benz OM642 3.0L turbodiesel engine by boxcab, as adapted from recommendations by TDIClub.com's member Drivbiwire for Volkswagen TDIs.

Rules that apply for the life of the car:

- When the engine is cold (below the first mark above the base of the temp gage) rev the engine to at least 2,200 rpms when driving. Avoid idling.

- When the engine is at or approaching normal temperature (above the first white mark to middle of the gauge) rev the engine to at least 2,700 rpms. The reason for this is to keep the turbo on boost, clear the VGT guide vanes and apply firm pressure to the rings for optimal sealing against blow-by gasses. The rings need the boost to seal since its a turbo-charged engine, Babying the engine is detrimental and will lead to issues with compression and cylinder glazing if done so for very long.

Break-in procedure

1. First 1,000 miles:

- Keep maximum rpm below 3,400. Avoid steady rpm. Frequent firm application of power is strongly recomended up to 3,400 rpm. Avoid the use of cruise control so that you naturally fluctuate the power with your foot.

2. 1,000-6,000 miles:

- Use the full 4,500 rpm power range. Avoid steady rpm. Avoid the use of cruise control. Frequent application of full throttle is recomended to help seat the rings. City driving is ideal for breaking in a CRD due to frequent stops and acceleration. Once you get to 6,000 miles change the oil and perform your first service per the manual.

3. 6,000-12,000 miles:

- Use of the cruise control is okay at this point since most of the initial break in has occured. Continue to use occasional full throttle accelerations to continue to seat the rings. You will notice the engine becoming slightly louder during this phase due to less friction from the engine breaking-in (it's normal for a diesel to become louder under lighter loads). If you're going on a long drive and are using the cruise control, every so often push the pedal firmly to the floor (don't stomp on it) to accelerate up above your previous speed by about 20 - 30 mph, then coast back down to your preset speed.

4. 12,000-60,000 miles:

- This is when the rest of the break-in occurs. It will take at least 60,000 miles to reach peak compression pressure. For the most part, once you get to 12,000 miles your compression will close to peak, meaning that most of the break-in has occured.

The main thing is to drive spiritedly, but without jack-rabbit starts and recklessness. Make that engine work!

StevethePilot

The only recommendation I got from my dealer (who will have to do the warranty work on the vehicle) is not to use the cruise control for the first 7500 miles, to allow more even initial wear on certain moving parts (the theory being, I guess, that a long time at a particular speed will cause a larger wear pattern on one part of the aforementioned moving parts, causing uneven wear).

The rest of it sounds just the tiniest bit like bollox.

kkuna

Quick question,

with regards to the first part of the break in that JH mentioned,
Is there an engine temperature monitor...I was just looking at pics of the dash and didn't see any engine/oil temp gauge.

thanks

kkuna

Quick question,

with regards to the first part of the break in that JH mentioned,
Is there an engine temperature monitor...I was just looking at pics of the dash and didn't see any engine/oil temp gauge.

thanks

lkchris

When you have total and trip mileage showing, press up arrow for temp gauge.

In your manual, of course.

lkchris

So does your dealer's recommendation.

The stuff in the owners manual is enough.

kkuna

Kent,

Thanks for the info. I can't read the manual because I am anxiously waiting for my GL to arrive. However, the lack of a temp gauge had me worried.

StevethePilot

Oh, I agree. I think a modern diesel engine, particularly - what is this, third generation? I think it takes care of itself. Anything too much about a "break in period" or whatever, if it's not in the owner's manual, it's voodoo as far as I'm concerned.

When you get a new Cessna, they have you go something like 100 hours without doing "touch-and-goes," supposedly a Lycoming recommendation. Some say it's a "break-in" period, but I say it's probably to make sure you're not spending a lot of time low-and-slow when the engine's too new to know if it's reliably built or not. Still, same thing - RTFM and all else be skeptical about.

StevethePilot

I think there's a temperature gauge in the multifunction display in the instrument cluster. I'm pretty sure I've looked at it before, when I lost my turbo hose and wanted to make sure the engine temp was okay. Don't have my user's manual in front of me but you can check when you get yours.

scottybdiving

That's correct. It is in C and I haven't figured out how to change it to F.

lkchris

You get a 1940s engine (as you know)!

Nevada Jack

I have never seen a F reading on the MB temp gauge (not saying they do not have one that reads in F.) They all read in C and run from 40 to 120. Normal is usually between 80-100 C. Exceeding 120 is where the warning message comes on.

gas-man

My dealer also told me to run the engine as described above. I was reading the manual which I think does not say so. I remember my dad had a 1980 300SD it was babied from the day it was delivered and 306,000 miles later( was given to cousin in 1997) it was still running with no issues. I do not want to compare this engine to the 300 SD engine ( 5 Cylinder turbo diesel) but I guess as StevethePilot says if this is the recommended break-in why was it not included in the manual?

StevethePilot

Except that now they do have fuel injection. But it's still a horizontally opposed, naturally aspirated (i.e. non-turbo) four cylinder running either 80 octane (green) or 100LL (low lead - blue) aviation gas.

I've asked in the past about why it seems like light plane engine technology has lagged so far behind and it's got something to do with high compressions at high altitudes, cooling (they're all air cooled except the new diesels in the Diamond Twin Star), and some other issues involving how the fuel is affected by high altitudes. Now, as for why we're not using turbines to run our cars on the ground, that's a matter of efficiency at extreme altitudes, and noise.

So how off-topic is this?

oknish

To convert C to F

1. Divide C by 5.
2. Multiply line 1 by 9
3. Add 32 to line 2.

You're done.

StevethePilot

You do this while you're driving? Man, I'm waiting until you're in Las Vegas before I get there!

oknish

Nah, I don't do temp conversions when driving. When driving I play license plate games figuring out squares/square roots/factorials. Keeps me awake