Both have the same problems, BUT that 2003 model is consided the "bridge engine" model.

It will have higher exhaust temps, and we have seen eroded turbo "hot" housings and exhaust "center sections", because of those temps, and in addition to that, CAT screwed up and had the fuel settings wrong on those engines and caused even more heat to enter the exhaust. It took them about 3-4 updates to get their fuel setting numbers correct.
 
On any 2003 C-12 engine, those numbers needs to be checked to insure that update/change got done WITH THE LATEST NUMBERS(fuel settings) Would have to have an ECM downloaded to tell if it ever got done.

Seen turbos and exhaust manifold ruined in less than 6 months, when this isn't done correctly.[ Note: also need to test the ATAAC core ("air to air aftercooler") to insure it holds boost pressure also.]
 
Also, the 2003 models have more exhaust backpressure(emissions muffler, catalyst), thus tend to get a little less fuel economy, too.( if you illegally install a regular muffler, that I've read on another truck site, some years ago, that the mileage comes back)

Don't currently have e-mail.  Currently, I'm living in a extended stay motel, until I quit CAT in Feb 2012.

 

1. probably just one hour of shop time (Seattle = $116 per hour)

fuel settings(Updated ones) are on an Excel speadsheet on CAT's website for mechanics and dealerships. Just need the engine serial number, then I or a dealer can look them up and post them.

Reprogramming?  If just changing some parameters = top speed, cruise limits, etc = just shop time = easy to do.
                                BUT , if you mean rerating to more HP, then that all depends? (parts, CAT Factory service charge, Shop time charge)

2. I don't deal with prices (just call a dealer/foreman for an estimate), I almost 100 % positive that there is no difference in the bolt pattern on CAT's rear flywheel housing(where the starter mounts) thus an electric starter should bolt right up.
Note: some trucks only use 3 batteries(total)
2nd note: A truck, with an air starter, still has a battery(run cab electrical), thus It should have a battery box already. [Question is: Is is big enough?]

It is possible, but "bridge engines" released in Oct of 2002, so unless the OEM truck builder had a big inventory , of CAT engines, setting in their warehouse, My best guess is that a 2003 truck likely has C-12 "MBL" serial number prefix = Bridge Engine.

If it is a "2KS" prefix, than it is a Pre-2003 engine.

Problems of C-12 engines;

 tend to be water pump weep hole can become plugged, thus when water pump seal leaks, it pushes coolant into the oil pan.
 
Next: the cylinder head gasket can seep coolant into the oil pan, BUT the new procedure and head gasket is a excellent repair= have great success, so if this has been done, it should be fine.
 
Next, the injector roller followers roller pin can fail , due to lack of interference fit between pin and its holder (there are updated parts for this= increase of the amount of metal for interference fit ) BUT it is an expensive repair=probably ruins cam, cyl. head must be pulled, and if cam is bad, then radiator and front cover must also come off. = $$$. CAT recommends ALL 6 get replaced(at customer's expense), during a repair, too(thus all get updated) Again, if this has been due, already, it should be OK.

Sometimes, We have seen failed valve cam followers, too, But not nearly as often has Injector cam followers.(Still expensive to repair) 

Question: Can you hear a huge, loud roar of the engine fan, WHEN you turn on the manual fan switch?

Reason, I ask is because we see this fan clutches, that have an alum. hub on them slip so badly, that the fan never really gets "locked up", They just sit there and spin at 400 rpm, when they should be at 2400 -2500 rpm(locked up), if the engine was at 2100 rpm.  
 
I would still change the thermostats and their lip seals make sure you stake in those lips seals, CAT even recommends "retaining compound on the metal edges", so they stay in their press-fit)  I just use an automatic center punch, and dimple the alum. right above the metal lips (about 12-15 dimples per lip seal) I just hold the tool at an angle to punch/dimple it.

I am unsure IF your fan circuit is operated by CAT sensor or Peterbilt sensor, probably a CAT sensor. There is the possibility that it reads incorrectly( reads low), thus it is sending an incorrect signal to the CAT ecm to turn on the fan. (least likely cause)

Check/listen for the fan and change t-stats first. 

That engine won't need any fuel setting adjustments, that issue is only with "MBL" serial number prefixes(=bridge engine) in the C-12 family.

That's probably a good choice, it should probably have the latest design of cylinder block and cylinder head, which has just a little more metal at the top deck of the block, and a little more surface metal on the bottom deck of the cylinder head. It uses just a little slightly different head gasket, so a little more material gets clamped down, when the head gets the "double torque-turn procedure" .

Some of our "used truck" dealers bring in trucks just for a wheel HP dyno run, take an oil sample(HOT oil), and record engine blowby, during the dyno run.

Just remember, this "one-time" oil sample is only a "snapshot", Plus; 

How much time/mileage is on the oil being sampled, anyways? 2000, or 12,000 miles???

It may alert someone to an immediate,upcoming  failure,  But stuff still can happen in 100-200 miles too, after person buys something. You just never know.

Oil samples, taken regularly,  are preferred to watch trends.


With those kind of miles, and no records, i would like to see a person install new rod and main bearings(= cheap insurance). Seems like many companies are trying to push the limits on these types of maintenance items, lately.


Six months ago, we replaced an engine, that spun a bearing (C15) and it had 1.2 million miles on it and the owner NEVER replaced bearings!!! Honestly, I am surprized he got that far. I think I heard it was a $28,000 replacement

A couple years ago, I rebuilt 2 C-12 engines, one with 965,000 and other with around 945,000 miles. This was for preventive maintenance, as the owner/company has these trucks on special routes(ran 2 shifts per day), and were happy with these trucks/engines/mileage; so they chose a complete inframe overhaul with all OPT options(water pump, turbo, 6 injectors) Note: OPT = Overhaul Protection for Trucks
Another plus was; no emissions issues, like if they had choosen to purchased newer trucks.

Buy the 2003 C-12.

Bearing parts are around  $700 with new oil and oil filter.  Shop would get $1600 for whole job.

I will attach some specs.

 If a person has time, I would jack up the front of the truck a little, drain oil, pull oil filter, oil pan and oil suction tube off, THEN let it drip overnight.
Next day, roll underneath, on your creeper, and wipe off oil drips. This way you will have a LOT less oil spots on your face and clothes. (We, and our clothes, look really bad, { from oil droplets} when we have to do these bearing replacements on trucks that just drove into the shop.)

Note: oil pump is external, so the oil suction tube just bolts to the side of the block, on a C-12 engine = nice.

No need to use plastigauge, just verify that the part number you remove , is the same as what you reinstall OR is the updated part number for that bearing that you remove = same size. Thus if you remove a standard bearing, then you reinstall a std bearing. Pay attention to your bearing "tangs". too.

Whereever you get parts, have them photocopy/print the parts screen, so you can see the part numbers and locations.

Main bearings, you will need long , narrow flat blade screwdriver and probably a "heel bar" .
I have a 4 piece Snap-On set that I use constantly.
 Once you push the upper bearing half (opposite the tang), you can then use the "heel bar" to lightly pry between block and the back side of that bearing half, that you are trying to remove, Just take little bits, and it comes out. BUT sometimes ,getting the new ones started is a challenge. 
If you can't get one, roll the crank(by hand, turning front bolts on damper probably) and turn it 90 degree and retry, or 180 degrees and retry, to insert it, with oil on the new bearing, of course. NOTE: All oil holes, in bearings go UP into block, NOT down in the main caps!!!!!  Don't laugh, I've seen it done= ruined crank.

I tend to do bearings, one at a time, thus no screw ups, BUT I just lightly tighten them but hand, then after all mains are installed, I do the whole torque/turn procedure for the mains = 14 bolts.
Rods for torque/turn method; you do 2 at a time (1,6);  (2,5);  (3,4) ; you can still just insert the new bearings, one cylinder at a time = thus, no chance of swapping rod caps!!!  

Don't forget some new silicone sealant at joints for front cover and rear cover areas, once oil pan rail is clean and wiped dry. 
 

C-12 2KS PREFIX MAIN BOLT SPEC.rtf (1KB - 1163 downloads)

C-12 2KS PREFIX ROD SPEC.rtf (1KB - 1135 downloads)