Q: Which diesel is most superior? 7.3 5.9 6.6

asked by on January 19, 2017

I want to know from a random diesel enthusiast or mechanic which diesel truck do you think is the best all around made. In terms of least problems and cheapest fixes (when things go wrong) between the 7.3,5.9(2nd gen),6.6(LLY) and I know everyone has there own opinion but I want yours. Thank you so much, I currently own a 5.9 and I love the truck, I'm just not sure if it's the better diesel of the 3. Apart from tranny problems and the fuel system I'm throwing money away. Which diesel from stock is the best all around, thanks!

The 5.9L diesel is a straight six engine. The 6.6L diesel and the 7.3L diesel are both V8 engines. If find that there are more maintenance when it comes to the V-configured engines to the straight six engines. I have worked on many straight six diesel engines and many V8 diesel engines over my career. Most vehicles with the straight six engines are usually having problems with the fuel filters and the fuel injection pumps. The V8 diesel engines tend to have multiple issues with the turbos, the waste gate controls, and tend to have issues with the engine performance with the glow plug circuits. I recommend staying with what you have unless you are wanting to go up in power and have more torque. I have seen a Dodge Cummins Turbo Diesel 24 valve put out 1200 foot pounds of torque and have over 600 horse power from stock settings with a smart box to change the pyrometer controls. A straight six engine is more comfortable in adjusting performance than a V-configuration engine.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I clean and protect the inside?
You want to keep the interior of the car just as clean and nice-looking as the outside. Use a vacuum cleaner to remove dust and dirt. Use a damp clean cloth to wipe down dirty surfaces. Clean leather areas with...
How do I recline the front seats?
Reclining the front seats is very easy. First, locate the recline lever, which is on the side of the seat, near the back. Next, lift the lever, and move the back of the seat into whatever position you desire. Finally,...
AC stops working when idling
It is possible that your compressor clutch is producing more drag than usual, causing the near stall at idle. When the engine RPM is raised, the belt rotates faster, forcing the compressor to spin. It is also possible that you...
Car won't start after someone tried to steal it
Two systems in the column need to work for the engine to start. The ignition switch, and the anti-theft system. Your car has some version of the Passlock anti-theft. The ignition switch reads a specific resistance of your key and...
Door lock not working well
When you say "not working well", it sounds to me as though the actuator could be getting weak, since this door gets locked, and unlocked the most. I recommend having the lock actuator replaced, after it is checked. I recommend...
After i changed the crankshaft position sensor, i have a code p0302 which is a misfiring code.
The crankshaft and both camshaft position sensors should be replaced at the same time. Nissan had recalls on these sensors. Also, a simple compression test should be performed to verify no mechanical issues exist. This car is known to have...
would a bad oxygen sensor keep my truck from starting?
The O2 sensor will not cause the no start. The no start can be caused by the fuel pump (https://www.yourmechanic.com/services/fuel-pump-replacement) or the ignition system. You should check the engine for spark and fuel pressure, when it is not turning on...
My car steering wheel shakes when I apply brakes. How can I determine if it is the front or rear brake issue?
The rule of thumb is: if you feel it in the steering wheel and the steering shaking back and forth when braking, then the front rotors are warped. If you feel the vibration more in your seat he seat of...
What parts will I need for a timing chain replacement and how many of each. Is my engine interference or non interference?
Hello - your engine does use a timing chain, and that engine is not an interference (valve-to-piston) engine. However, having said that - if the chain breaks, especially at anything above an idle, the broken chain can jam the crankshaft...

Related articles

Are Low-Profile Tires More Prone to Puncturing or Bursting?
Low-profile Low-profile tires are becoming more commonplace as manufacturers build vehicles or provide options suited to more visually-discerning or performance-oriented clients. They are tires that have short sidewalls which is noted by the second number in the tire size. For...
How to Install an Aftermarket Air Intake
Trying Trying to squeeze more performance out of your car can be an expensive and serious undertaking. Some modifications can be simple, while others can require that the entire engine be disassembled or the suspension be completely rebuilt. One of...
How to Maintain a Car at 50,000 Miles
Maintenance at the 50,000 mile mark is critical. These services include inspection of the exhaust, suspension, fuel caps and filter, and tire changes.