Diesel maintenance is a little more expensive, more oil, higher cost oil filters, water separators, fuel filters, etc. But there are no spark plugs, spark plug wires, etc to buy so it's probably fairly even.
A diesel needs to come up to temp before it's used hard, and short trips to and from the store are bad news for a diesel. It used to be that everyone idled their diesels if it meant having to shut it down for a short period. But now the excess fuel washes the oil off the cylinder walls so it's not good to idle.
For alot of heavy towing, or full timing a diesel seems to be the better investment, but it will take some time to realize that extra up front cost, maybe 150,000 miles depending on the difference in fuel costs.
Most folks never keep a TV long enough to realize any savings in their diesel truck. Most folks never tow enough to realize any savings in their diesel truck. Most folks are not aware of the extra cool down period a hot turbo needs. Most folks are not aware that the extra weight of the diesel engine reduces GCWR. Most folks get about the same mpg solo in their diesel as gas owners do, some get the same towing as gas owners do.
You can't drive a diesel like you can your Camry, this isn't a bad thing, but it is the truth.
And after your diesel has gone 250,000 miles, and it should, but your truck has fallen apart around you, then what ? Diesels have lots of torque, torque is twist, rear ends, drivelines all wear from torque being applied. Front ends wear from having to try and swing weight that wants to go straight around a corner, and springs wear from supporting the weight of the front end after repeated bounces, diesels weigh more than gas engines so this wear is accelerated somewhat.
Lots of torque at low rpms are good, diesels do that well but the torque may be peak at 2000 prm while the hp peak is at 3500 rpm where torque is much less. Gas motors make torque at a higher rpm AND make hp at a higher rpm, but you have to get the motor to the higher rpm to be able to use it. Stop lights with a heavy fifth wheel are better with a diesel. Modern, fuel efficient, low emissions gas motors have come a long way, just as diesels motors have.
So it really comes down to what you are requiring your tow vehicle to do. For big, heavy loads that you tow alot, a diesel is the choice. But for 90% of us who tow occasionally and trade our trucks in every 3-6 years, the gas engine is more logical.
My trailer is not huge, it's 24'. We plan on going to 28-35 sometime soon as the kids are much larger now. But we will still be around 10-12K which will still get us over the top of the mountains just as fast as the diesels. The tow rating on the big gas motors now is similar to what was only diesel territory until just recently. Will a 460 ft lb gas motor beat a 600 ft lb diesel with a 20K fiver on it over a mountain top ? No, probably not, but for us, probably the majority of the towing population, we don't tow a condo on wheels. I've owned lots of diesels, turbo, DI, non-IDI, turbo kits, I like them, but they do have drawbacks, as do gas engines.
Ken, wife-Kathleen, 6 kids, 11-25 yrs. 24' bunkhouse towed by the almighty Ford V10 in an ext length E-350.
