Super Duty Diesel Decision: 6.0 or 6.4?

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Super Duty

After one FTE member’s beloved Super Duty was stolen, it’s time to find a replacement. But which diesel engine should he go with?

We’ve all been there. While some decisions in life are simple (like more cheese? Of course!), others can be pretty darn difficult. One such difficult choice is which Super Duty diesel engine you may want to choose, and which ones you may want to run away from. Throw in unknowns like how a particular used truck was treated, and you’ve got a potential headache in the making. Which is why Cjinx did the smart thing and resorted to the Ford Truck Enthusiasts forums for advice on his big Super Duty diesel decision!

“Recently had my baby stolen, a 2001 7.3 4×4 Crew Cab. It had 270k on it. I had finally gotten all the bugs worked out from the previous owner who ran it into the ground. So now I’m looking to get another PSD. That being said, I am working through my options.

First option would be to go with another 7.3. But I’m afraid of getting back in the swing of taking it to the shop every month while I get things like driveshaft, bearings, leaks etc. replaced. So now I’m looking at either a bullet-proofed 6.0 or 6.4 with about 100k miles. I figure if I’ve got that low mileage with a BP’d engine I should be good to push 500k if I take good care of it. So here’s my question: which is the better engine? Or should I just pony up and go for a 6.7?”

Super Duty

As you might imagine, the responses to this question vary greatly. Some, including maticuno, recommend the 6.0.

“If you can find yourself a low mileage 6.0 that is completely bone stock and hasn’t been abused with just regular maintenance, you’ll have a truck that will last forever.”

But the vast majority recommend the OP just go with the newer 6.7, for obvious reasons. Among them, speakerfritz does an excellent job of breaking down the pros and cons of each choice. Well, except maybe the 6.4.

“The 6.7 has design modifications that address some of the problems of the 6.4 and 6.0. Bigger lifters, more headbolts, oil spray on the rocker arms, free to air rear water pump so it no longer leaks into the oil system, etc.

The 6.0, when bullet proofed AND dealer proofed becomes a very reliable engine. If the heads were not shaved AND the correct length push rods were used. The push rods come in two sizes. And if you do not use the shorter size when the heads are shaved, you wind up having cam and lifter problems. A lot of folks who worked on the 6.0 did not take that into consideration.

Super Duty

The 6.4 is a difficult engine to say good things about. It is extremely sensitive to aging of the emissions system. Runs hotter than desired and pushes the mechanical limits. This engine is plagued with torched pistons, spun bearings, cavitation of the water pump, EGR leaks, clogging DPFs, head gasket problems, cracks in heads and cylinder walls due to hot spots, etc. I own one and every day when I turn the key I ask if this is the day that it will go BANG.”

Some folks even go so far as to recommend gas engines. But the OP has pretty much settled on a diesel for his next Super Duty. So we want to know – what do you think about this trio of engine options? Tell us which one you would choose, and why, by heading over here. And be sure and read up on the rest of the informative responses while you’re there!

Join the Ford Truck Enthusiasts forums now!

Brett Foote is a longtime contributor to Internet Brands’ Auto sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts, among other sites.

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