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Diesels For Dummies

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2020 Chevrolet Silverado 3.0L diesel 33 MPG

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Diesels For Dummies: Answers for diesel engines then older truck reviews, along with MrTruck’s words of wisdom and general truck knowledge

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Thanks to Crystal B. for asking.

Diesels For Dummies Intro:

How do diesels work?: What is the difference between a gasoline and diesel engine?

Compression; Generally diesels have twice the compression of a gas engine and require compression and heat to explode diesel fuel. This requires diesel engines to be built heavier than gas engines that use spark to ignite the gasoline. The exploding diesel is one of the reasons diesel engines are louder. High compression in a diesel creates the heat needed for combustion but for fast starting truck manufactures heat the fuel and air going into the engine. Ford Power Stroke uses glow plugs in each cylinder;  GM Duramax diesel has glow plugs and an intake manifold heater. Dodge Cummins diesel has an intake manifold heater to help start the engine.  Glow plugs warm up the cylinders before the fuel gets there and a manifold heater warms the air going into the engine.

Diesels For Dummies

Glow Plugs;

For glow plugs and manifold heaters, the indicator light is in your dash. You want to wait
until the  indicator goes out before starting the diesel. After you drive it and it’s warm and you shut if off and restart it while the engine is still warm, wait for the light to go out then also. It will cycle shorter when warm ( or
shut off sooner,) but your glow plugs will last longer if they are off when your engine explodes the fuel.

If it doesn’t start right away I would cycle the glow plugs again, especially when new.  When a diesel is new it doesn’t always start right away. This will get better after it’s broke-in. The important thing is not to start the engine with the glow plug still on and use them each time you start the engine. But if the glow plugs are still on and you start it, the red-hot glow plugs are getting the force of the exploding fuel. This will prematurely wear out the glow plugs. They should normally, the glow plugs and the solenoids that control them, last over 100,000 miles. I figure if 90% of the ambulances are diesel and they can wait a few seconds for the glow plugs to go out, I can too.

It will realistically take 5000 miles to break in your new diesel engine. You can pull a trailer after 500 miles, but the diesel will start faster, get better fuel economy and run smoother after 5000 miles. Read your owners manual, about the break-in period, which is generally 500 miles. Engines are ran-in while on the engine stand and the oil changed before they go into your truck. This is why your first oil change is the same interval as a normal oil change. In the old days the engine was ran-in (broke-in) by you and you needed to change the oil at 500 miles. During your first 500 miles you shouldn’t pull a trailer and you need to vary the RPM’s, (don’t use the cruise control.) This allows the rings and valves to seat properly through out the RPM range and not leave any ridges. Also on a diesel it will take close to 5000 miles before the fuel mileage stabilizes and it will start faster. New trucks have learning computers. They will actually adjust to how you drive. Which means they will have more power when they are past the break-in period and if you want them to say shift at a higher RPM then you need to accelerate more when you drive.

If you live in cold country I sometimes run the glow plugs twice before I start the engine. If you have below 10 degrees winters, you may want to plug in the engine block heater that comes with the truck. I used a $12 plug in timer from Wal-Mart and just have the block heater turn on for 2 hours before I needed the truck in the morning. Because water condenses in your fuel tank, especially in cold temperature, keep you fuel tank over 1/2 full in winter. You’ll need
to drain the water out of the fuel filter once a month in winter and less often in warm weather. Check out your owners manual for more details. Above this article on the Insider Club home page are pictures of the different fuel filters and instructions to drain the water.

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Warming up and cooling down,

I would also recommend getting the diesel to operating temperature when you drive it. I would avoid short trips where you turn it on and off without reaching normal operating temperature. Getting the diesel engine to operating temperature burns off the water (moisture) condensation in the engine. Avoid prolonged idling too as it will build up
carbon inside the engine and shutting off the engine after prolonged idling can glue that built up carbon to the engine. It’s also wise to get to operate temperature before pulling heavy loads. Most of the turbos in modern engines rotate on bushings not bearings, so if you shut off a hot engine under a load there is no oil pressure oiling the bushing in the turbo while the turbo spins to a stop.
Diesels are designed for long life and power from low RPM torque.

If you take care of them, you can expect 250,000 to over 300,000 miles. You need the first 100,000 miles to pay for them. Diesels are addicting, enjoy them!

Diesel vs

Diesels For Dummies


Payload – Pulling Capacity;

Diesels For Dummies pulling trailer

Along with the increased payload and towing capacity for 2005, Ford can say they did something physically to the truck instead of just increasing the numbers that some manufactures do. The 2005 Super Duty has a thicker one piece frame with more gussets, thicker axle tubes on their Danas, larger brakes and a factory brake controller that I like. Each truck has jumped a model, so the new F250 is rated like the old F350 dually and the F350 dually is rated like the F450 etc. The F250 4×4 which will only come with a 3.73 axle ratio, I’d get limited slip, camper package, tow package, (best mirrors) Tow command trailer brake controller. Ford won’t have a major body change until 2007 with hopefully a larger Supercab.

A month ago Ford dropped off a 2005 F350 crew cab for me to tow horse trailers with for an article on their TowCommand trailer brake controller. Article out soon. 

The early 99 model was the first year of the new Super Duty model by Ford. The diesel V-8 badge is up by the headlight. The late model 99 has the Power Stroke Diesel badge on the front door. Ford skipped the 1998 truck year and came out with the Super Duty early, the early 99’s had a few problems with power steering pumps, bolts on the left front spring hanger and some spring bushings. And I’d get the automatic transmission. Diesels have twice the compression of a gas engine, so you have to shift them faster. The auto tranny will give you a smother ride for the horses too. The only rear axle ratio you can get in a Ford without going F350 duals is 3.73 which is fine and it’s the only axle ratio available for GM. Dodge diesels before 2003 had a 3.55 or 4.10 axle ratio. The 4.10 is better for trailers. The automatic tranny comes with an external tranny cooler so no problem there. Dodge had the worst of the automatics. They can be rebuilt better if you want to figure that cost into the purchase price. Good automatics in diesels didn’t come until 99 in the Ford Super Duties. 2001 GM Allison and 2003 with the Dodge 48RE.

Diesels For Dummies

  • Differential;

    Diesels For Dummies- differentials

    GM does have a locking rear differential option now where Ford and Dodge have limited slip axle that will be a big help along with the 4×4. It’s the biggest buyers market I’ve seen in over a decade. Dealers are starving; large rebates and 0 interest aren’t working anymore. For some reason dealers are holding out on used truck prices more than the market
    would seem. I think it’s just the used car salesman mentality. Because the market is flooded and $2 fuel, the war, uneasy economy all point to lower used truck prices.

    Dodge is going to have the edge on longest lasting diesel engine. Dodge will also be the cheapest of the three diesels and longest of the drive train warranties at 7 years or 70k miles. All of the diesels will have 5 year 100k warranties. Ford and GM sell 90% auto trannies in the 3/4 tons and up. Dodge is up to around 60% auto’s now because they have had a weak auto with their diesel that was improved in 2003 but is still just a 4 speed and locks up the torque converter clutch in 2nd, 3rd and OD.

Centramatic Automatic On-board Tire and Wheel Balancers

Diesels For Dummies
2004.5 GM Duramax was improved in January. I have more at, . Have you taken any test drives?
Dodge introduced in Dec. the 2004.5 “600” torque diesel, . Their new transmission in 2003 Dodge diesel came out with the improved 48RE auto that can take the torque of the diesel. It’s a 4 speed, but the torque converter will lock up in 2nd, 3rd and 4th, which helps with towing. But GM and Ford have 5 speed automatic transmissions and lock up the torque converter in all 5 gears, giving you the control of a 5 speed manual, a big help going down long grades.

Dodge changed their 4×4 in 2003 to be similar to GM with the whole front axle always moving, with only the transfer case shutting off. 02 and older Dodge HD had a vacuum system that disconnected the right front axle. Ford is the only part-time 4×4 you can buy. It comes with an auto hub called shift on the fly which is a vacuum impulse hub engagement with an over-ridding manual hub and you can buy a complete manual hub system. I like to be able to completely shut-off a 4×4 and the Ford is the only one that does. That’s my theory on having parts moving and wearing when not needed. Though GM has had it’s 4×4 system running all the time now for decades and just a few problems even with a CV joint front axle verses Ford and Dodges U-joint.

An auto is easier to drive with a diesel and better warranty. The 5-speed auto’s in the Ford and GM get close for fuel mileage to a manual tranny and are so easy for handling a diesel. The GM and Ford 5-speed auto’s lock up the torque converter in all five gears and downshift the same
mechanically like the clutch and pressure plate in a manual transmission for slowing you down and holding the gears in tow mode down shifting (grade shifting) for you with the brake pedal. Diesels have 5 year or 100,000-mile warranty, the rest of the truck is 3 year or 36,000 miles,
(longer on Dodge), but that doesn’t cover wearables, like belts, hoses, tires, windshield wipers and clutches. So if the auto tranny has a problem it’s covered by the bumper-to-bumper warranty.

Diesels For Dummies – pulling loaded trailer

The HD trucks have become very competitive since 2001. And this is a good thing. Reliability is close, comfort even the ride is now close, for fat boys like me the Dodge and Ford seats fit me the best, but for normal size folks, the GM seats are the most plush. It takes close to 100k miles for the fuel economy of a diesel to pay for the extra cost of a diesel option.  And diesels can have 3 times the cost of an oil change verses gas engines. What really brings people to buy a diesel is they get addicted to the power. The largest truck in body size and power is the Ford crew cab Power Stroke. The Dodge and Ford diesels were new models in 2003; the Ford had many problems and the Dodge proved itself. I would have bet the other way around at the beginning of the model year.

Model year 2003, the Dodge has shined with all the changes from the ground up. It had new boxed frame, new axles, transfer case, diesel engine, bed, brakes, wheels, etc. Ford had many computer control bugs with the powerful new 6.0L Power Stroke in 2003, much better for the
2004 model year.

2005 Ford diesel
engine is virtually unchanged with 10 more FT. LBS. of torque. The frame though is thicker, with more gussets, axle tubes thicker and front suspension now like Dodges coil springs with much better turning radius. With the new GM Allison and the new Ford TorqShift all 5-gears will lock
the torque converter so it can work like a clutch and pressure plate for slowing you down and holding the gears in tow mode down shifting for you with the brake pedal.

On the Insider Club home page under Bulletins are some of the problems Ford is having with the first year blues. According to Ford they had the bugs out of the new 6.0L PS diesel in February with the R13 upgrade to the computer controls download but are up to R16 upgrade now. I’ve seen and driven some of the last 2003 Super Duties built in May and June and they
had some bugs for loosing power until you reflashed the ignition to reset the ICP.  But on the folks that I know that bought the 2003 Ford, 90% of them were very happy. I know of at least 100 trucks that got bought back by Ford that couldn’t be fixed easily and the upgrades were
up to R16. So buying a 03 was risky, but the ones without bugs were fun to drive. I had one for a couple of weeks and pulled a horse trailer over Trail Ridge at 12,000 ft. The truck ran great. But before I left Denver I couldn’t get over 60 mph. So I pulled over and reflashed the
ignition 3 times and that reset the ICP and it ran great. I talked to the Blue Diamond boys from Ford/Navistar who were touring the country with a trailer with cut-a-way engines and displays in it stopping at Ford Dealerships explaining the fixes that Ford was doing to the 6.0L PS. They had the same problem and pulled over and reflashed the ignition 3 times and it cured their truck.

The ICP sensor will be on the front of the engine instead of the back in 2004. The glow plugs are longer and the injectors are no longer pilot injection. Pilot injection is a smaller shot of fuel at the beginning of the compression stroke to get the hot air and fuel burning before the main injected fuel explodes the compression stroke down for power. GM’s Duramax started using this in 2001, Dodge and Ford the 03 model year. The purpose of pilot injection (two-stage) is quieter diesel engines and better emissions. Ford hopes the more basic injection will be more
dependable. Ford also has concluded some hydraulic problems with the 03 injectors came from foam in the oil and is recommending a Stanadyne anti-foam additive for the engine oil.

Ford’s problems are in my opinion because of the fight Ford was having with Navistar, the folks who build Ford diesels. The same engine in the Ford truck the 6.0L Power Stroke has been in the Navistar 4200/4300 2-ton truck called the VT-365 for a year with few problems. But Ford dumped on Navistar by backing out of a V-6 diesel deal that Navistar had already built for Ford for 200 million. They have settled the case last summer and now with Navistar and Ford on the same team will fix the bugs. And they are even going to build the V-6 Power Stroke diesel again
for the 2006 Ford Low-Cab-Forward trucks.

Diesels For Dummies 

The GM Duramax as proven itself and the Allison automatic is as good as it gets for a truck auto tranny. Also the variable intake turbo charger that Ford introduced in 2003 6.0L Power Stroke is now in the GM Duramax with a Ford chief engineer jumping ship from Ford to GM. But GM has that low cross member supporting the Allison tranny and has the least clearance. I can’t even slide under the cross member without jacking the truck up.   With December 03 as a build date, Dodge increased the power in the HO
Cummins diesel to 325 horsepower and 600 #’s of torque. GM Duramax built in January 04 have the power boosted to 310 horsepower and 590 torque using a similar variable vane turbo like the new Ford 6.0L Power Stroke. Dodge increased their torque in their diesels to 610 for 2005 and GM Duramax went to 605. But pulling trailers with all three diesels is very close for power.  I like the Ford diesel a little better than the GM Duramax, but I like the GM Allison automatic tranny as the best built and you’ll have transmission problems before diesel engine problems, hopefully closer to 200,000 miles. But I would rate the Dodge Cummins as the best of the diesel engines rated to last 350,000 miles, with Ford and GM rating their diesel life at 250,000 miles. So Ford is in the middle of the three for long life.

GM only has 3.73 rear axle ratio’s, so no wrong choice there, I’d get the limited slip or locker rear differential and lowing package. GM has a trailer mirror option that telescopes and folds at the push of a button, from Power Vision. Ford has the largest crew cab, followed closely by
GM. GM is a little lower to the ground for getting in. I like the GM bench seat better. Especially with leather in the GM bucket seats, they have a folding armrest that makes that part of the seat thicker. This makes my back twist to the side. I like to set facing directly forward. What I’d do is drive the GM Duramax HD 2500 and the Dodge 2500 and look at ride, ease of getting into, braking etc. and see which one gets you. It’s going to be a decision between the best tranny (GM) and the best diesel (Dodge), the new Dodge 48RE is a good transmission now. But if
you are going to keep the truck 200,000 miles, I’d go GM, if 300,000 miles plus, Dodge. Ford flew me to their Arizona proving grounds in June and they haven’t changed the power much but have made the frame and axle housing thicker. To Ford has changed the front leaf springs to coil springs like Dodge, still with a mono-beam axle, so they turn about 5 ft. shorter in a circle than before and you will be able to buy a built in the dash trailer brake controller for your trailer. It’s very smooth. I pulled 15,000# trailers on their track and on the interstate and the truck and trailer brake system was impressive.

Dodge increased their torque in their diesels to 610 for 2005 and GM Duramax went to 605. But pulling trailers with all three diesels is very close for power.

But the situation changes every couple of months. GM purposely slows down diesel production and is low on Duramax’s now. Ford with the new truck, will be more interested in moving the 04 model. So economically, the Ford and Dodge would be a better choice now for a couple of months. The Ford will be louder at idle. On the road, the Ford diesel will be quieter. Also try to roll under a Duramax at the transmission. I don’t fit. Ford has more clearance.

For price research go to to put together the 2004.5 or 2005 GM HD 2500 and 2004.5 or 2005 Dodge 2500 to see invoice price and option prices for the trailer package, limited slip axle, trailer mirrors and whatever options you want get the invoice price. For Ford invoice prices go to
for a F250 to be armed when getting prices from retail or fleet. And if you’re a business, don’t mess with retail salespeople, always go directly to the fleet department and get the fleet rebates off invoice prices. Cars Direct as linked to the Insider Club home page can help get the best price on new. They will get you the best price first, upfront, so you’ll know if your price is close. I can’t out negotiate Carsdirect and they are different from the internet
buying services like, Autobytel, Autoweb, Invoice Dealers, FordDirect,
Stone Age etc. Those guys just refer you to a dealer and get a fee. Carsdirect sets a price and gets a dealer to sell for that.

Diesels For Dummies – By MrTruck.

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