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So I am not a diesel guy but am aware that in general the diesel engines hold up for a really long time in the big trucks. But what about the pick ups in the las10-15 years? In my case I am considering a change that would require more power than my current 6.0L Chevy. It sort of looks like I may have to go diesel and am wanting the bargain of the older trucks. I am seeing some good prices on older ones that have in the 200,000 mileage range. I even found a 6.4 in the 90K range for decent. Knowing that other things will wear out like the Tranny I am trying to get the facts together and think some others might be interested in the responses so I brought it up here.

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I can only speak of what I have experienced. I've been driving a '99 F350 7.3 Diesel for several years and about 140,000 miles. That diesel engine, tranny & drive train that goes with it were made to last. More than likely the body is going to rust out around you before major issues will show up. That being said, every ones driving & care habits are different so that will impact how long any vehicle might last. I would buy diesel again without hesitation. Ford had some bad years right after they changed from the 7.3 so check out some diesel forums before buying used.

Todd

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Proper maintenance is the key to diesel engine life, of particular concern to the small engines you are looking at is the proper level of SCA in the coolant. That prevents erosion of the cylinders which leads to a block failure. Good records would give me a much better feeling, a full set of oil and coolant tests would be worth it to me if the systems haven't been freshly flushed.

 

Doing the research on the year truck and engine you are considering is also important, some years/brands had issues you want to avoid as mentioned above. Also just because it has a diesel doesn't mean it will be suitable for your towing needs, dig out the full set of weights (axles, total, towing and combined) and make sure that the loaded weight of the fiver you are considering and the scale weight of your truck loaded to travel is going to work. Differential gearing is important here, lower gears tow more but only by spinning the engine faster trading top speed, MPG, noise and wear for the additional weight. If you are pushing the limits of the truck on combined weight be aware that driving as you approach the maximum will be harder on you and the truck and that may make driving it less than enjoyable and relaxing.

 

Where the truck has spent time is another consideration. an Arizona or even snowbird truck is going to be a lot longer lived than one splashing salt for a long Michigan winter.

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A co-worker here was just talking about his pickup and how it has 216,000 miles on it. He mentioned it was getting ready for a transmission rebuild. So, you may see a good deal on the truck but that could simply be just before the threshold of tranny work and someone is trying to unload it before it goes. I suggest seeking professional advise to get an opinion on the one you are looking at.

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The only light duty truck diesel engine that will truly last a while ( in my humble opinion ) is the Cummins inline six. I would trust it to go a good long while. Ford and chevy V8 diesels....not so much.

 

One of the best is the old pre emissions and simpler 5.9 Cummins . They were a little anemic power wise stock but can be greatly tweaked to put out significant power and they will last a long time. There is a shop in Great Falls, Montana that speciallizes in installing these engines into any pickup truck.

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We had a 99 model F-350 with a 7.3 diesel. Folks here said that the transmission was the weak link, good for 150 to 160 K miles. Ours kept pretty much to that average. We traded it with 370k miles showing but it was still in good condition. The replacement vehicle is a 2011 F-350 with a 6.7 diesel. I could not believe the difference. This one takes off from a traffic light almost as fast as a car and I'm talking when towing a 13,000 lb fiver. The bells and whistles are nice but the towing is excellent. I might be in for surprises later but for now I really like this one. The only negative is that fuel mileage when not towing is only about 15 - 16 mpg. Towing, it runs 9 to 11; significantly better than the 7.3. BTW, I have no problems with a Chevy or Dodge; just happened into this Ford.

Russ

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I tore down a 2001 Cummins 5.9 in 2010 that had 255,900 miles on it. Before it was removed from the truck, a full diagnostics was performed on it, everything was within Cummins specs. On tear down, 1 injector showed wear on the tip, and the #6 cylinder head area showed signs of having been warm a time or two <_<. On measuring all the components, pistons, rings, cam profile, rods, lifters, bearings, everything was in good shape. There were wear patterns, but that is to be expected with that many miles. If I had been doing a stock rebuild, very little would have had to been done to the main parts, little honing, paint the block, replace the oil pan- or knock the dent out of it (don't ask), new gaskets and put it back together. I went a little more high performance and did aftermarket parts and go fast stuff, but there was no reason that engine wouldn't have continued another 250k miles.

I used synthetic oil, changed every 5,000 miles, with new filters- oil and fuel, oil and filters are cheap, engines are expensive.

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Early '99 7.3 Ford - 6 speed ZF manual trans - 400K on the clock, 75K pulling 12K fifth wheel.

 

1 injector, handful of glow plugs, 2 clutches. If the body wasn't being dissolved by the ehm wonderful stuff they deice the roads in the north, it would still be pulling.

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Proper maintenance is the key to diesel engine life, of particular concern to the small engines you are looking at is the proper level of SCA in the coolant. That prevents erosion of the cylinders which leads to a block failure. Good records would give me a much better feeling, a full set of oil and coolant tests would be worth it to me if the systems haven't been freshly flushed.

 

 

 

I can't speak to small diesels in pickup trucks, but SCA's aren't an issue any longer with large diesels running extended life coolants such as CAT ELC, These require no SCA monitoring and should last for many years. Last year I started to buy an "extender" for my CAT ELC since that had been the 3-year recommendation when I first had it installed. Now, however, extender is not recommended except at mileages I am never likely to reach.

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docj or others:

I am seriously looking to buy a 2000 newmar running a 325 Cat. My questions are:

1 - What is the interval and cost to do a lube job on these older Cat engines?

2 - What are the maintenance tasks required on the Cat engine that would not be needed on a gasser?

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Proper maintenance is the key---wish I had done this for my body. This is helpful. If I change out anytime soon I won't be bumping up to something huge. (the rv) It is a stretch to change both at the same time. I have known a good number of gasers that are holding up real well with the aforementioned proper maintenance so I kind of assumed the diesels should hold reasonably well when cared for. For physical issues I am limited to an automatic. The 6.4 08Ford I looked at with the 90k miles was most likely a former lease from the Chemical plant areas near Houston based on some paperwork I found in the truck. I looked close for signs of corrosion but looked pretty good. This was as much a learning process as anything at this point I was checking the owners manual, truck weights, etc. One thing that I was not aware of is there is a coolant reservoir for the fuel. this was an F250 and I will probably go for some type of 350 if I decide to go to the diesel side. Who knows as flaky as I can be sometimes I might even consider a dually. """"shudder"""'

 

As always thanks for the insight, bigjim

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I haven't checked on swapping the factory recommended small diesel coolant plus SCA and testing for the long life stuff but you can bet I'd look into that if I still had one.

 

The problem is when someone buys one of these engines and doesn't add the SCA, it can kill a heavily loaded engine fairly quickly and "holes in the block" aren't a repairable item. Checking when you buy is great but a recent dose can hide years of neglect and aside from pulling the heads so you can see into the block's water jacket I don't know how you'd see the potential problem areas.

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docj or others:

I am seriously looking to buy a 2000 newmar running a 325 Cat. My questions are:

1 - What is the interval and cost to do a lube job on these older Cat engines?

2 - What are the maintenance tasks required on the Cat engine that would not be needed on a gasser?

 

My CAT C-12 has a recommended oil change/filter interval of 15,000 miles or one year. Since I rarely drive that much in a year, I simply change the oil during my spring service. Cost will vary depending on how much a shop charges and how much oil the engine holds. Mine takes 36 quarts; the smaller ones not as much. Depending on where I have it done I pay ~$250-350 for oil, filter and lubing the chassis.

 

Diesels also have a set of "every 2-4 year" items that I handle on a rotating basis. These include transmission filters, air dryer elements, etc. Each of those is typically ~$200-400.

 

With a 2000 I would definitely check to see if the transmission fluid has been upgraded to Transynd (or equivalent) which is the only fluid Allison now recommends. It was introduced until a couple of years after that coach was built. I've discovered that quite a few owners have chosen not to upgrade because it is expensive (~$500-600 total cost) but the benefits are huge in terms of transmission running temperature and, therefore, lifetime. The fluid change interval, essentially, becomes infinite as far as RVers are concern; only filter need be changed if you sample your fluid and send it for analysis. It's very difficult to tell visually if the fluid is Transynd; unless the owner can prove it with receipts I would definitely take a sample for analysis.

 

Similarly, a 2000 CAT would have been delivered with "normal" glycol coolant (green). When I bought mine four years ago, it had been very well maintained and the owner had provided extensive records but he had not converted the coolant to the new extended life variety (red) although he had switched the transmission fluid to Transynd. The CAT folks I was dealing with at the time were quite surprised that anyone was still running glycol since ELC totally eliminates the SCA issue and greatly extends coolant lifetime.

 

If you perform the recommended maintenance on either a CAT or Cummins diesel it should provide many miles of service. However, unless you do all the maintenance yourself it can easily cost $1000-1500/year for routine service PLUS the unexpected repairs that can occur. Yesterday, during our spring service visit, while flushing the brake lines (we have air over hydraulic brakes in our MH), the technician discovered that we had a bad valve in the air portion of the system. Since brakes are always nice to have working, we had it replaced. The valve was readily available and only cost ~$100 but it took ~3 hours of work to remove the old one and mount the new one. An unexpected >$400! It wasn't the fault of the diesel, per se, but it was an example of the fact that these coaches are complex machines that consist of a lot of parts, any of which can break.

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The mentioned era of the 7.3 is a proven performer over the years. As well as some years of the Cummins 5.9. Between the two, I'd go with the one with he best documented care. Have it inspected by a professional, and pull an oil sample for analysis.

 

That being said, with interest rates as low as they are today, hearing good things about both the newer Ford and Dodge diesels too... If this is a 'keeper' truck for say over 5+ years - you might also do the math to see if a low interest longer term loan is something that might work for you too. Possible you might come out ahead lower maintenance costs, as well as future resale - and be money ahead in 5+ years when you want to exit from this truck. (Just picking the 5+ years as an example.) The Total Costs of Ownership, and then exit, might pencil out for you... (And yeah, higher DMV and Insurance costs too - not trying to dodge these....)

 

Best of luck to you on your search!

Smitty

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If I switch and luck into a good one I would keep it a decent period of time. Financing is not an issue. I just don't want to put out the money the newer ones cost until I decide if I like a diesel and I learn by hands on. At this point a truck could last longer than I do. I actually lean toward the plainer trucks like the work truck configurations. The one I looked at the other day had paperwork that made it easy to determine the gearing (3:73). I would lean toward a 4:10. I am told there is a way to determine this from the VIN # but haven't figured out how yet. If anyone knows I would appreciate the info. A Ford service writer told me he could tell if I furnished the him the VIN but who wants to keep doing this over and over, maybe when you narrow it down. Also does that hold true on the VIN for the Chev, and Dodge?

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I haven't checked on swapping the factory recommended small diesel coolant plus SCA and testing for the long life stuff but you can bet I'd look into that if I still had one.

 

The problem is when someone buys one of these engines and doesn't add the SCA, it can kill a heavily loaded engine fairly quickly and "holes in the block" aren't a repairable item. Checking when you buy is great but a recent dose can hide years of neglect and aside from pulling the heads so you can see into the block's water jacket I don't know how you'd see the potential problem areas.

Stan - FWIW - I changed to the CatELC at 50K and at 350K added the 'extender' in the '99 in post #8, 50K miles ago. I guess it's working. Coolant pump started to leak (at the weephole) about 25K miles ago. I add about a cup of coolant in the spring and fall.

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Don't understand why ya'll discount GM. Mine is a towing beast. This is my second truck, previous 05, and very reliable trucks. 05 in shop one time over fuel line from tank failure. I put over 250k on it and only got 12 for increased towing ability.

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Glenn....in my post I replied to the OP's question about longevity of the engines. For short term and low mileage I think the Duramax with the Allison tranny is hard to beat but I would not count on trying to get 500k out of it.

To me the perfect truck would be the Ford's comfort with the Cummins engine paired to an Allison 6 speed with a retarder and a good exhaust brake on the engine.

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Sorry Glenn - I've owned the 7.3 for 16 years and 450K miles. I'm not saying the Cheby isn't a good truck, I've just never owned one. I looked at the Chevy before buying, but they were just coming off the 6.2 , ah conversion gas engines, and I got the ZF manual 'cause I knew that would hold up (lot of burned trans back then) and stay in the gear that I wanted coming down the mountains and run through the exhaust brake.

 

And I should disclose that I worked for Chrysler, wanted a crew cab to hold the family, and Chevy and Ford were the only 2 contenders at the time. Dodge quit building crews from 1986 to about 2008. (Yes, I know they had that stupid 1/2 cab about 2002. If you sat in that for a couple of x,000 miles, "what were they thinking????" comes to mind).

 

And the world headquarters made me park a mile away summer and winter.

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There are Duramax out there with 1 million miles. Personally I would not own a truck with multiple 100k miles. My GM was in good shape at 250k but was getting somewhat worn looking. But they have been mostly trouble free. Also love the Allison for towing.

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There are Duramax out there with 1 million miles. Personally I would not own a truck with multiple 100k miles. My GM was in good shape at 250k but was getting somewhat worn looking. But they have been mostly trouble free. Also love the Allison for towing.

 

You're wasting your breath. There are those who are stuck on old technology. Good friend has a 2006 Dodge he calls "The Beast". He spent $4,000 on Banks equipment to "get the most out of it". I still pull away from him on every mountain pass we encounter in my stock Duramax. And, I'm towing the heavier trailer.

 

Like you say, there are plenty of Duramax's out there being used commercially with high mileage. The Cummins is a fine, proven powerhouse which will give lot's of care free miles. But, it's definitely not the only one.

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You're wasting your breath. There are those who are stuck on old technology. Good friend has a 2006 Dodge he calls "The Beast". He spent $4,000 on Banks equipment to "get the most out of it". I still pull away from him on every mountain pass we encounter in my stock Duramax. And, I'm towing the heavier trailer.

 

Like you say, there are plenty of Duramax's out there being used commercially with high mileage. The Cummins is a fine, proven powerhouse which will give lot's of care free miles. But, it's definitely not the only one.

 

 

Guys, this was my bad, I thought the OP asked about Ford or Dodge, so I responded the way I did. Nothing wrong with the Duramax. The Chevy/GM, Ford and Dodge - all had years with some problems with either engine or transmissions.

 

The OP was stepping up due to a heavier load, so no matter what, he should understand the power to weight ratio of any truck in relation to what he plans to tow. Some early years may be a bit softer on power then he may want to consider.

 

Best to tall,

Smitty

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I had a 99 model F-250 with a 7.3 diesel towing a fifth wheel that had 180,000 miles when I traded it. Replaced the tranny at 80k, avg tranny mileage with heavy towing then was said to be 40k. Replaced the electronic injector controller, 1 injector, water pump, and alternator none of which was covered under the diesel engine warranty. Never had any problems with the engine itself.

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FWIW I bought a 1994 Dodge 3/4-t pickup with the 5.9 Cummins in it in 1995 for work on our farm when it hat 34,000 miles. We already had a 1993 Dodge 1-t dually with the 5.9 engine on the farm. We sold the 1T when we sold the farm but kept the 3/4T. It has 225,000 miles on it and it's only had a new injector (Bosch) pump and a new clutch. Both trucks were 5-speed manual.

 

I figure 20 years - 15 of it on a farm and driven by farmhands in typical duty - is a pretty good testament to the durability of that truck, engine and transmission. It's hauled hay, horses, ATVs, lumber, dirt, rocks, a cabover camper, an Alaskan camper, a 29-ft Alpenlite 5th wheel, and a 21' Streamline (1970s) trailer. It's pulled a 26' sailboat and a 25' Carver sport fisher on trailers.

 

We used it today to pickup a new sofa for a close friend who is moving.

 

It really, really needs new paint.

 

I paid $16,000 for it in 1995. I figure I got my money's worth.

 

WDR

 

Edit: I plan on keeping the truck 'til I die and the DW will probably keep it after that. Maybe I'll have it painted.

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One comment I'll make, if you are prone to doing your own wrench pulling the Dodge Cummins is in a class of it's own. I do most all of my own maintenance and upgrades. The access to the Cummins due to it's in line six configuration is superb. I never miss a chance to peek under the hood of the V8 diesels and I can't imagine doing any repairs on them.

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