Diesel or Gas?

BobbyJones

Observer
Hi All.

There's probably a better place to ask this, but I really only visit this area of the forum and I'd like to hear the thoughts on diesel vs. gas motors.

I'm intending to make the transition to a full size Truck or Van and have been swaying towards diesel for the seemingly better gas mileage and alleged longevity.

I say alleged longevity, because the more I ask, the more I question the statement. When I hear "I've got 250K" it's usually followed by I replaced the injectors at 100k for 3k. Or I had the engine bulletproofed for $6k. Or a new transmission.

I suppose any vehicle will go 300k if you keep throwing money at it. I'm curious if these kinds of things are just blown out of proportion or the norm.

I'm one of those "to each their own" guys and not trying to stir the pot. But I'm coming from a long line of mostly imports where I've seen 150-250k of fairly trouble free service. Not perfect, but not 5k "maintenance" bills either.

Trying to get an idea of what I'm in for.

Thanks!
 

caideN

New member
There's probably over thousands of discussion of this subject on many forums. I think ultimately it's personal preference.

I think most can agree that diesel is reliable, gets better mileage than gas, is more expensive to repair, louder, can pull more, and easier to modify for performance.

I think most can agree that gas is just as reliable, gets less mpg, is less expensive to repair, less noise, can pull a decent amount (V10) but will never match a diesel in the same caliber, and not as easy to get a lot of power out of it with mods.

You said it yourself, most vehicles can go 300k if taken care of and these trucks/van are no exception.

Good luck on your choice.
 

4x4pair

Adventurer
Of course there's a lot of other things to consider, but just keying in on what I think you're asking...gas would be the way to go. Diesels have a lot of advantages, but in my opinion, low maintenance cost is not one of them. When people talk about diesel "longevity", they're mostly talking about the block and internals. As for the other stuff like injectors, HPOP, sensors, etc...they do wear out at "normal" intervals and they are very expensive to fix/repair.
 

Bikersmurf

Expedition Leader
A lot depends on how many miles you're going to put on in a year. BC Ambulance always used 7.3 Diesels... they replaced them with 6.0 Diesels... the 6.0s were replaced (often prematurely) with Chevy Gassers. I've read that the 6.0 maintenance costs were so high that gassers cost less for the Province annually.

Long story short Gasser or lower mileage 7.3 (for a fair price). 6.0s can be great, but they can be money pits. I talked with an ambulance driver whose friend spent $26k in in a week for repairs for his 6.0 Excursions (not sure how many but I couldn't afford that).

I happened to look into it earlier today... worst case 8 injectors for a 7.3 can be had for around $1200 USD. Treated right they'll last 500k miles... In contrast, you can likely buy a complete rebuilt 7.3 for what a set of 6.0 injectors will cost.

I've crunched the numbers on fuel savings for my 4x4... driving it 5k miles a year, I'd only save $200-300 a year by converting to diesel... 10 years later I'd break even with the cost of installing a higher mileage diesel. If anything went wrong in those 10 years... it could be 20. So it stays gas.

I do like getting 22 mpg highway in a 9000 lb camper... with the 7.3 it's doable... a couple trips to the shop with a 6.0, and I'd have 2 or 3 times as much into it.

How many miles? Towing big trailer?
 
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kpec

New member
Another consideration is that while the 7.3's are great motors, the transmission may be the weak link. The E4OD is not the greatest in stock form. I had to rebuild mine at 124k for about $2200. That was no upgrades, just a stock rebuild. With a motor that can easily go 500k it would be nice to have an auto that can match it...
 

ujoint

Supporting Sponsor
Yes, massively subjective topic! In our world (92 to current Ford vans) I've been recommending gas more & more lately. Easier to find, just as (or more) reliable, always cheaper to own in the long run. If you do the math on initial purchase price, fuel costs at a certain mileage a year and maintenance gas is always cheaper unless you drive a bazillion miles a year or tow like crazy.

The 4R100 is a good transmission, especially after a quality rebuild (needed with a 4x4 conversion) but still not as good as the 5R110. In my opinion the best combo is a V10 with the 5R110. Especially the 05/up vans with no RSC.
 

86scotty

Cynic
Chris, owner and builder of many amazing diesels, has seen the light. :D

I agree completely except for the 'gas just as reliable as diesel statement'. The fact that you have to do a lot to the diesels to keep them reliable negates the definition of reliability to me. 5.4s and v10s don't need anything at all to keep on running, and they're not any less efficient when you start thinking about $100 dollar oil changes, additives, etc. on diesels. I'd say go with a V10 without a doubt for a 4x or camper build, but if you do there will be one less out there for me to buy. Bummer. You can do a lot with a 5.4 and a 5-star tune, and 5.4s are everywhere, cheap, and run forever.

YMMV
 
I just did a full engine rebuild, full cooling system, all sensors (except knock sensor, forgot), every hose, radiator, water pump, all tensioners and idler pulleys, belt, starter and alternator, etc etc to my gasser 4.6 for ~$3500

No labor, I did it all myself, over the course of 3 weekends and one week day (7 days total, but not more than 8hrs/day more like 4-5hrs) at a mild pace, not frantic.

Pretty stoked to have a lil gasser, wish it was a 5.4, but the 4.6/4r75e/8.8/Weldtec 4" lift combo is a nice light duty rig for me and my needs.
 

luthj

Engineer In Residence
Yes, massively subjective topic! In our world (92 to current Ford vans) I've been recommending gas more & more lately. Easier to find, just as (or more) reliable, always cheaper to own in the long run. If you do the math on initial purchase price, fuel costs at a certain mileage a year and maintenance gas is always cheaper unless you drive a bazillion miles a year or tow like crazy.

Obviously there is some variance depending on what platform and brand you are looking at. But this is pretty spot on. Diesel engines in the USA do not make much financial sense in the light passenger market. For commercial and heavy trucks it is a different matter.

The 2007+ emissions requirements add additional operating and maintenance costs that are simply not offset by reduced fuel costs (if any) and perceived longevity. To compound things, the percentage of light passenger vehicles sold with diesel power plants is quite low. This means that used parts including low mileage pull outs, and junkyard motors is low compared to their gasoline counterparts.

Now if you step up to the big engines, such as Cummins or CAT the longevity and improved reliability are substantial. By big, I mean engines with 10L or larger displacement. These applications burn a lot more fuel, so fuel savings adds up.

An interesting example is irrigation engines in the kansas farmlands. These engines will run nonstop for days pumping water to irrigate whole fields. Cat diesel engines (around 10L) are often used. Rebuilding one of these engines is $9K in parts alone. For this reason, many farmers opt to use gasoline fueled V8 engines. Despite the higher fuel cost, these engines are cheap to rebuild or replace when they grenade and require minimal capital investment up front. Part of the lower rebuild cost is due to larger tolerances in the machine work, and the sheer volume of parts produced for the automotive aftermarket.

If light diesel engines had the same volume here in the USA as they do in europe; and if gasoline was as expensive as it is across the pond, diesel powerplants would make a lot more sense.
 
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mgmetalworks

Explorer
My advice...as I'm just finishing up a swap from a 5.4L gas to a Cummins Diesel... go buy a gas engine Econoline, perform regular maintenance on it and it will last you forever. AND have a conversation with your passengers the whole time. :sombrero:
 

Corneilius

Adventurer
My advice...as I'm just finishing up a swap from a 5.4L gas to a Cummins Diesel... go buy a gas engine Econoline, perform regular maintenance on it and it will last you forever. AND have a conversation with your passengers the whole time. :sombrero:

Best advice I've ever heard :sombrero:
 

86scotty

Cynic
Man, there's more wisdom being shed in this, the 7 billionth gas vs. diesel thread than I've ever read, especially by LuthJ and MG above. Oh, and me of course but of course I would think that. Diesel engines in the U.S.A. are one of the most convoluted, bass-ackwards problems we have with our government and the 1% that rule us. Europe and the rest of the world have the right idea. Diesels make more sense, they just don't make more sense for us. Look at all the cool adventure rigs in Australia and South America, and they're all diesel, and of course not to mention you can get any small or large Japanese pickup in diesel and they're unbeatable.
 

Bikersmurf

Expedition Leader
One other thought I'll throw in. If you're one of the rare few who are planning to circumnavigate the globe, consider the fuel that will be easiest to get where you'll be. Also consider parts availability in the remote places you'll be traveling. Overall it's a lot easier to carry a spare set of plugs and a set of points than to carry the parts to repair/replace a set of injectors. That won't do you any good if you can't readily find gasoline (or diesel) where you're travelling. Propane and CNG have a lot of advantages... but it's hard to find places to fuel up. They'd be right up there with electric... great economy, but it'd suck in the desert.

My Fj40 has a points 350 SBC, and I'd not change that. It's as simple as can be, and if it grenades almost any Chevy V8 or 90 deg V6 will bolt in. This means parts are cheap and readily available.

The ambulance has a 7.3... I love it. It's a blast to drive. Very comfortable to drive on the highway and around town. I wouldn't go in search of a diesel or pay more for one, but at the price I paid it was too good a deal to pass up. A new set of tires (stock size) is worth more than I paid to buy it. In 3 years the 7.3 has only needed oil changes, a fuel filter, and O-Rings for the fuel bowl. I can't complain.

Getting to my point... I agree with others, buy a gasser unless you're towing a 10,000 lb trailer... or get a screaming good deal on a Diesel. Based on what I've read, I'd not buy a 6.0 or for that matter any Ford diesel than a 7.3. Including everything I've got into mind, it's less that bulletproofing a 6.0.
 
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