PHeller wrote:
codrus wrote:
For power at altitude you want a turbo (it'll make extra boost to compensate for the altitude), but that's either the newer Ford with the turbo V6 (not cheap enough yet) or a turbo diesel which are going to be very high miles at $7K.
I guess my question is, if those miles are mostly highway miles, and the truck is in great shape otherwise, should I still be worried? Lets say its a 7.3l Ford, what's a common issue for them at high mileage? Likewise with the Cummins?
Tough one to answer. Here's the short answer IMO: If you can't drop the coin for a decent, lower-mileage diesel, I would avoid them. A $7000 diesel is possibly a good deal but hard to tell. Just like with a 100k-mile gas car, it depends on how it was treated. When you're talking about a 300k-mile diesel truck, there is a lot more room and time in which abuse can take its toll.
Both the 7.3L stroke and the 5.9L Cummins are usually a very long-life engine. Even in commercial heavy duty applications they don't expect rings or bearings until 600k miles. Even then, its more of a preventative thing than needing the repairs. Usually those commercial versions are derated a bit (180-230 hp let's say) compared to the pickups, but still very reliable engines.
The 7.3L will need a steady diet of glow plug relays approximately every 60-100k miles. Napa GPR104 or GPR109 are your part numbers depending on if you have the plug-in style or the bolt-on style. Last time I bought one it was $68 and they are right on the top front of the motor and take 20 minutes to replace. After a very long life (I would guess in the 150-250k range) you'll probably need a cam position sensor. I think they're more like $175 and I honestly haven't replaced one. Its a DIY swap for sure, but its down on the front of the motor somewhere.
94.5 - 98 trucks did not have an intercooler. 99-03 did have one. This alone didn't cause huge performance gains, but its nice to have one if you plan on modding in the future. Keep this in mind, however: The older boxy trucks had nice engine bays. The 99-03 trucks with the newer body style have a strong rake to the windshield and a set-back engine. If you ever need to do head gaskets or turbo work you will most likely have to take the cab off the truck. Seriously. Question is... can you find a 94.5-98 truck that isn't either A) completely wasted or B) in really nice shape and commanding $15,000?
Powerstrokes use an HPOP (high pressure oil pump) to provide pressure for fuel injection. Because of this, oil change intervals (all 14 qts of it) are a little more important. The abuse that a powerstroke gives its oil can be pretty intense.
Cummins are darn near bulletproof. There are three basic versions of the 5.9L: 89-93 (ish) VE pump, 94-98.5 P7100 pump 12-valve, and 99-03 P7100 24-valve. Starting in 03 they went to a high pressure common rail injection. I won't talk about the 6.7L Cummins because you won't find one for $7000.
Early Cummins Dodges had what owners call a KDP (killer dowel pin). Its a dowel behind the timing cover that can work its way out and drop into the timing chain and cause major damage. Many 24-valve owners insist on using an upgraded fuel lift pump. There is a traditional electric fuel pump that supplies the high pressure injector pump. If the lift pump fails it can cause expensive failure of the injector pump. Earlier 12-valve engines used a more reliable cam-driven mechanical lift pump.
One caveat to Cummins trucks: Dodge automatic transmissions are not up to the task. 46RE and 47RE transmissions are not only weaker compared to the Ford and Chevy offerings, but they are hideously expensive to rebuild. Its not necessarily that the Cummins makes more torque or power, its how it makes it. The Cummins makes bigger power events every 120 degrees versus a V8's 90 degrees. The result is a huge difference in the violence and abuse seen at the crankshaft. Ever notice how a Cummins belt squeaks when it shuts down? That is the voilent torsional forces the engine creates. Combine that with their weak transmission and its a recipe for disaster. I have seen snapped input shafts, shattered drums, split pumps, torrington bearings scrubbed flat... Not pretty. The solution is to make sure to get one with an NV5600 manual. It will still rattle it to bits, just not as fast.
Keep this in mind: Diesels for us enthusiasts on a budget are getting very difficult to find. With the last 7.3L rolling off the line in 03 (and subsequent 6.0 and 6.4L versions being a whole can of worms), it means trying to find a 7.3L stroke that isn't wasted beyond belief is very difficult. I lucked into a 99 stroke in an E350 van with 99k on it, but I had to pay almost $6000 to get it. That same setup in an F250 would have been $15k.
Cummins follow the same basic thing. The last of "the good ones" rolled out in 03. The newer common-rail 5.9s are just bloody expensive. The resulting demand for these trucks keeps them remarkably expensive.
There is a silver lining, though. The Duramax has been a wonderful engine for Chevy. There is a very high demand for them keeping prices high (because the 'stroke and cummins buyers are pushed into looking for better diesel options in the 03-08 years) but they are plentiful enough to keep them affordable.
If you get an early LB7 (01-04.5), make sure the injectors have been done. They were a common failure point and they are under the valve covers and use o-ring sealed cups that often fail as well. They are just a pain to replace. Later Dmaxes had the injectors outside the covers and are much easier to replace. The 05-07s are your unicorns. LBZ/LLY are the ones that are the sweeties; VNT turbos, external injectors, and before all the DPF/Urea equipment that kills MPG.
The added bonus to getting a Dmax is the Allison transmission.
All of this I present without bias after a decade or so of running repair shops including tranny repair shops. I have very strong opinions about the trucks themselves which I will omit. That's up to your taste. Offering opinion on the truck itself is kinda like getting a Trump voter to switch to Bernie.