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Is a Cat 3406 a good engine?

142K views 14 replies 9 participants last post by  WHMARRS1942 
#1 ·
I'm looking at a semi tractor converted to an RV hauler. It has a Cat 3406 engine. Is this a good engine?

Should it have had an in-frame yet at 645,000 miles?

Brian Elfert
 
#2 ·
I think it's a great engine. However I would like to know what version it was. A, B, C, E whatever.
 
#3 ·
The 3406 is an awesome powerplant and has been used in long haul truck for nearly 20 years.
 
#4 ·
Yes it is a good motor. Like what has already been said, what model is it? A, B, C, or E? It does make a difference. I like the B and C models better than some of the E models. There was a number of years that the E models had problems with cooling, and the heads would crack from overheating. If you can tell me the serial number on the motor if its an E, then I can tell you if you are okay or not.

Mike.
 
#6 ·
If it is the original engine, it should be a B model. The C model came out in 1991. So it may even be a late 1990 truck with an early C model. I think you are looking at a B model though. Great motor. It is all mechanical. When tuned right, that motor really screams.

Mike.
 
#7 ·
[ QUOTE ]
If it is the original engine, it should be a B model. The C model came out in 1991. So it may even be a late 1990 truck with an early C model. I think you are looking at a B model though. Great motor. It is all mechanical. When tuned right, that motor really screams.


[/ QUOTE ]

It is definitely all mechanical according to the current owner.

It sounds like this will be a very good engine if I choose to buy the unit.

Brian Elfert
 
#8 ·
I had one of those in a Peterbilt 379LN (rated @ 425 h.p.). The one thing you will want to pay attention to is when did the bottom end have a bearing roll done. Also, never run it low on coolant --> it'll crack a head » they seem notorious for this. I would highly recommend this engine.
 
#9 ·
My 90 KW with a 3406B 424 HP is still running with 1.3 million on it.
Never had the head off, on my 4th set of bearings and lost count of water pumps /ubbthreads/images/graemlins/eek.gif think it's 7 or 8 water pumps.
Great engine /ubbthreads/images/graemlins/smokin.gif
 
#10 ·
I had some notsogood luck with a couple 3406 PEEC motors, I guess they were the early C's? They both ended up getting switched back to "B" models with mechanical pumps, and are still running strong at around 900,000 miles, last I heard. Good motors, maybe a little harder on fuel than a Cummins, but darn long-lived with a killer powerband.
 
#11 ·
[ QUOTE ]
I had one of those in a Peterbilt 379LN (rated @ 425 h.p.). The one thing you will want to pay attention to is when did the bottom end have a bearing roll done. Also, never run it low on coolant --> it'll crack a head » they seem notorious for this. I would highly recommend this engine.

[/ QUOTE ]

What the heck is a bearing roll? Never heard of it.

I suppose I should go to a Cat dealer and see what they have to say about this particular engine.

Brian Elfert
 
#12 ·
A bearing "roll in" where they put in new rods and mains, and only drop the pan to do it.
Usually about 800 bucks used to be done every 300K to 350K on the "B" series engines, not required on the "E" series like I have, unless oil analysis says to do it.
 
#13 ·
Don't worry. It is a great engine. I promise. The bearing roll is not a big deal either. The E models do get the roll, but not until about 5 or 600K. Its kind of like pm on the motor. You could check with a local Cat dealer and see if they have any records on this truck. Not a bad idea. How many miles are on it now? See if you can find out when the last few services were done, and what they did.

Mike.
 
#14 ·
Awesome engine! I haven't turned mine up to much. People will call me a liar but I'm getting 10 mpg with empty flat deck and 7.5 loaded. Canadian gallons. Timing can be fickle but if you keep it tuned you will be happy. I put a liter of 2 cycle oil in every fill. Must say TC-W3 on the label though. I put a Duralitd Air Cooler on as well. Enviro save really helped cool it down too.
 
#15 ·
I just have a Quick Question: I haven't driven a 3406 Cat for many Years - so, I am going on old age memory here.
Am I correct ? The 3406A & B were both running on a Mechanical F. Injection Pump, But the 3406C went to an Electronically Controlled pump about 1990 or 1991 - Correct ? ? Also, Are there Any shops left that can Rebuild/ Overhaul the old Mechanical Pump ? Some current operators may Need this Info. Thanks to You All !
 
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