Newer diesels... the good, the bad, and ugly?

[Tyania]

Lots of info on the pre 2004 diesels on this forum. I know most prefer and purchase those but...

Since I am forced to buy 2004 or later, I could really use some help to know what to look for and what to avoid mechanically (and in general if there is something I should know about) in regards to the shorter conventional style buses.

Would love info on expected life span, reliability, parts and repairs, milage, and anything I am leaving out.
It's all new to me so in simple terms.

[jctrembly]

The easy answer. Buy 2004 and older, there are plenty around, a good place to look is here on this forum.

2005+ equals emission controls. Different years have different levels of emissions but they will all cost more to maintain than a 2004 or older. Any engine with an EGR valve is an emission engine.

Example: the truck I drive for work is a 2014. We have about 325K on a Cummins IXL9 liter engine that is 90% interstate as the purpose no this truck isn't go between Maryland and Vermont. This engine is designed for many miles. Ryder Truck has "invested" about $20K in fuel injectors, EGR valves, turbo intercooler, and Several DPF's. All due to emission controls. It doesn't cost that much to overhaul the engine. School buses by nature are stop & go, which is the worst operating environment for an emission engine.

The main thing is Body Condition. If it's rusty...

Cats are $$ to buy parts for.
5.9 Cummins are not big powerplants but are reliable.
DT466 - GREAT engine/ non computerized/ not as powerful
DT466E- not as easy to work on as an DT466 but more powerful and fuel efficient, it is computerized.

8.9 Cummins, hard to find but they are a nice find.

Transmission if it starts with and "AT" as AT545 its automatic and does not have a torque converter lock out = more fuel usage. (You don't what it with a 466 engine as it's too much power)

The more desirable is the MD-3060 or the "World" that replaced it.

The rear end, I'm sure of the ratio off had, but many buses are geared to hit 55-65 at the governor. That hard on fuel and the engine.

There is a TON of info on this site where the Pro's and Con's have been gone over. Grab a comfortable spot, and just go thru it. This place will be a great help to you.



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[PNW_Steve]

Originally Posted by Tyania

Lots of info on the pre 2004 diesels on this forum. I know most prefer and purchase those but...

Since I am forced to buy 2004 or later, .

I hear a lot of negative about the Maxforce engine which is the current version of the DT-466.

I hear less negative and some good about the Cummins ISL.

The 6.7 Cummins seem to have a reasonable rep.

Take this with a grain of salt though. I have not owned any of these engines. This is all based upon what I have heard from folks that maintain them.

Overall it appears to me that Cummins may have done a better job of engineering their emissions equipment.

[cadillackid]

Originally Posted by PNW_Steve

I hear a lot of negative about the Maxforce engine which is the current version of the DT-466.

I hear less negative and some good about the Cummins ISL.

The 6.7 Cummins seem to have a reasonable rep.

Take this with a grain of salt though. I have not owned any of these engines. This is all based upon what I have heard from folks that maintain them.

Overall it appears to me that Cummins may have done a better job of engineering their emissions equipment.

there are multiple MaxxForce engines.. the Maxxforce DT is probably the best of any Maxxforce you will find in a school bus.. the Maxxforce 7 was V-8 diesel.. the Maxxforce 7 was the ford 6.4 (came after the VT-365{VT-365 has a bad rap..}..Maxxforce 9 was a larger I-6 and similar to the DT,, I dont know much about the engines once they reached the maxxforce name.. anything Maxxforce has the full complement of emissions systems on them..
-Christopher

[Tyania]

Originally Posted by jctrembly

The easy answer. Buy 2004 and older, there are plenty around, a good place to look is here on this forum.

That is the answer eveyone wants to give which is why I stopped reading through the forum and started this thread. I absolutely cannot purchase pre 2004 buses. I would if I could, trust me. But I am bound by Mexican importation regulation, my permanant residence. So there is no way around it and I only need info on 2004-2010 models.

Originally Posted by jctrembly

2005+ equals emission controls. Different years have different levels of emissions but they will all cost more to maintain than a 2004 or older. Any engine with an EGR valve is an emission engine.

I thought it was 2004 and on that have emission controls. Was it not put into effect until 2005 models?

Do the engines get progressively worst or better as the emission years went on?

Originally Posted by jctrembly

The main thing is Body Condition. If it's rusty...

Cats are $$ to buy parts for.
5.9 Cummins are not big powerplants but are reliable.
DT466 - GREAT engine/ non computerized/ not as powerful
DT466E- not as easy to work on as an DT466 but more powerful and fuel efficient, it is computerized.

8.9 Cummins, hard to find but they are a nice find.

Transmission if it starts with and "AT" as AT545 its automatic and does not have a torque converter lock out = more fuel usage. (You don't what it with a 466 engine as it's too much power)

Thank you, thank you, and thank you.

Originally Posted by jctrembly

The more desirable is the MD-3060 or the "World" that replaced it.

Don't recognize that one. I will research it.

Originally Posted by jctrembly

The rear end, I'm sure of the ratio off had, but many buses are geared to hit 55-65 at the governor. That hard on fuel and the engine.

I seem to remember reading somewhere here that the limiting speed can be changed/removed/or something???

Originally Posted by jctrembly

There is a TON of info on this site where the Pro's and Con's have been gone over. Grab a comfortable spot, and just go thru it. This place will be a great help to you.

Indeed, I am slowly sifting through the seemingly endless info. The forum is a great resource but slightly overwhelming in quantity and varying opinions.

[cadillackid]

buying a bus that is 2004 or newer you wont have to deal with non-overdrive automatics.. by then you will either find an allison 2000 series (most conventionals), allison 1000 series (van cutaways and light duty IC BE style shortie), and the allison 3000 (MD-3060).. in the big engined and many Rear engine busses..

you shouldnt run into any AT545's..

2007 / 2008 are the years that FULL emissions (DPF / DEF fluid) were required in school busses.. theses are more complex and more failure prone than the 2004-2006 (Ive heard some 06 had it.. but mainly 07 / 08 and newer)...

EGR existed in 04 and up.. it had issues in some engines.. the Navistar VT-365 was the one which had the most issiues with its EGR system.. its very similar cousin to the Ford power-stroke 6.0. the VT-365 didnt have as many issues as its ford counter-part however it is what began to give the emissions diesels a bad rap.. (international built the engines for ford .. with a few changes between the 2)..

the DT-466E was still around in 2004 and probably one of your better choices even with its EGR system on it...

Various cummins offerings were available as well and they did ok..

there are also caterpillar and mercedes engines that also began with EGR systems in 04.. these are found in your freightliner chassis many times.. the only downfall to these engines is that they are very expensive to fix.. the computer software is held close to the chest and required to diagnose emissions issues..

Navistar gives their software away for free that will work on all engines up until they became MaxxForce names (09+??).. the hardware device to use the software is a few hundred bucks..

-Christopher

[Tyania]

Originally Posted by PNW_Steve

...Overall it appears to me that Cummins may have done a better job of engineering their emissions equipment.

Originally Posted by cadillackid

there are multiple MaxxForce engines..

Thank you both.

[Tyania]

Originally Posted by cadillackid

buying a bus that is 2004 or newer you wont have to deal with non-overdrive automatics.. by then you will either find an allison 2000 series (most conventionals), allison 1000 series (van cutaways and light duty IC BE style shortie), and the allison 3000 (MD-3060).. in the big engined and many Rear engine busses..

you shouldnt run into any AT545's..

2007 / 2008 are the years that FULL emissions (DPF / DEF fluid) were required in school busses.. theses are more complex and more failure prone than the 2004-2006 (Ive heard some 06 had it.. but mainly 07 / 08 and newer)...

EGR existed in 04 and up.. it had issues in some engines.. the Navistar VT-365 was the one which had the most issiues with its EGR system.. its very similar cousin to the Ford power-stroke 6.0. the VT-365 didnt have as many issues as its ford counter-part however it is what began to give the emissions diesels a bad rap.. (international built the engines for ford .. with a few changes between the 2)..

the DT-466E was still around in 2004 and probably one of your better choices even with its EGR system on it...

Various cummins offerings were available as well and they did ok..

there are also caterpillar and mercedes engines that also began with EGR systems in 04.. these are found in your freightliner chassis many times.. the only downfall to these engines is that they are very expensive to fix.. the computer software is held close to the chest and required to diagnose emissions issues..

Navistar gives their software away for free that will work on all engines up until they became MaxxForce names (09+??).. the hardware device to use the software is a few hundred bucks..

-Christopher

Super helpful. Exactly what I was asking for. Thanks for taking the time to write it all out.

[cadillackid]

governors - there are 3 things that control the maximum and cruising speed of a bus... there is the computer limiting speed control.. it was often programmed to keep drivers from exceeding safe speeds on the highway

there is your maximum engine RPM... what is the redline of the engine? it varies.. what is the Max-power RPM? before you reach edline you reach an RPM where your engine outputs its maximum power.. that RPM is designed to be reached when you are accelerating on a ramp or into traffic.. the max RPM is simply where you dont run it above that.. it is limited by the computer.. and cant be changed (or shouldnt).
your optimal Cruising RPM on the freeway is generally 400-600 rpm Below the max power output RPM.. (if you need more power to grab a hill your transmission should downshift you into the max power RPM range when you punch it)..

Gears and tires - your rear gear Ratio, tire size, and final overdrive gear ratio of your transmission affect what your maximum reachable speed is also.. and at what RPM you are spinning the engine at a given set speed.. I know with navistar products you can call a dealer service dept with the VIN number and they can give you what engine, transmission, what rear gear ratio, and what tires originally came on the bus...

armed with that info you can use an online rpm calculator to figure your RPMs vs speed..

many of the newer allison transmissions (2005+) are built as 6 speed transmissions but are installed and computer limited to 5 speeds in aschool busses. . there are a number of people who are working on seeing what it takes to get the computer program altered and 6th gear "unlocked" this is a possibility that would lower your RPMs when cruising if it can be done..
-Christopher

[Tyania]

Killer info.

Originally Posted by cadillackid

I know with navistar products you can call a dealer service dept with the VIN number and they can give you what engine, transmission, what rear gear ratio, and what tires originally came on the bus..
armed with that info you can use an online rpm calculator to figure your RPMs vs speed..

Nice tip.

Originally Posted by cadillackid

there are a number of people who are working on seeing what it takes to get the computer program altered and 6th gear "unlocked" this is a possibility that would lower your RPMs when cruising if it can be done..

I will be watching for that on the forum.

Thanks again.

[EastCoastCB]

Originally Posted by jctrembly

The easy answer. Buy 2004 and older, there are plenty around, a good place to look is here on this forum.

2005+ equals emission controls. Different years have different levels of emissions but they will all cost more to maintain than a 2004 or older. Any engine with an EGR valve is an emission engine.

Example: the truck I drive for work is a 2014. We have about 325K on a Cummins IXL9 liter engine that is 90% interstate as the purpose no this truck isn't go between Maryland and Vermont. This engine is designed for many miles. Ryder Truck has "invested" about $20K in fuel injectors, EGR valves, turbo intercooler, and Several DPF's. All due to emission controls. It doesn't cost that much to overhaul the engine. School buses by nature are stop & go, which is the worst operating environment for an emission engine.

The main thing is Body Condition. If it's rusty...

Cats are $$ to buy parts for.
5.9 Cummins are not big powerplants but are reliable.
DT466 - GREAT engine/ non computerized/ not as powerful
DT466E- not as easy to work on as an DT466 but more powerful and fuel efficient, it is computerized.

8.9 Cummins, hard to find but they are a nice find.

Transmission if it starts with and "AT" as AT545 its automatic and does not have a torque converter lock out = more fuel usage. (You don't what it with a 466 engine as it's too much power)

The more desirable is the MD-3060 or the "World" that replaced it.

The rear end, I'm sure of the ratio off had, but many buses are geared to hit 55-65 at the governor. That hard on fuel and the engine.

There is a TON of info on this site where the Pro's and Con's have been gone over. Grab a comfortable spot, and just go thru it. This place will be a great help to you.



Sent from my Nexus 5X using Tapatalk

DT466 is plenty powerful. Available up to at least 250 hp.

[jctrembly]

Yes, the 466 went to 250hp,. I have one [emoji16] it's officially the DT466HT (High Torque)

For what you want, find a 5.9L or an 8.9L Cummins pre-DPF. That is the best engine for emmision issues. Seems so many were made each the bugs were worked pretty well.

Avoid anything with a DPF. That's the exhaust filter. The local Maxforce DT buses had big Regen issues. You can do a DPF delete and EGR delete but that's a whole different can of worms. Done right, they're great. Done wrong...

Cummins places a fuel injector in front of DPF, during Regen it sprays fuel directly in to the exhaust stream causing DPF to burn the gunk out.

The Maxforce DT just dumps more fuel into the cycliders. Enough to go past the rings and dilute the engine oil. Enough so, it wasnt uncommon to find a gallon of fuel in the engine oil. Or pull your dipstick and oil/fuel gushes out.

The mechanics replaced injectors, o-rings and other stuff for little improvement.

The only fix was International finally offering the 5.9L (then the 6.7L) in their buses. Yup, the maxforce with a DPF was so bad they were loosing sales and finally agreed to put a Cummins in them.

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[cadillackid]

..theres definitely a good reason navistar doesnt build engines anymore

all the brand new IC busses have cummins
-Christopher

[Tyania]

So which bus makers used the Cummins engines inthe 2004-2009 years?
IC didn't start until 2013. I found their engine/year pairing on this site... https://cptdb.ca/wiki/index.php/Inte..._Engine_VT_365
Freightliner seems to go with cats, detroits and mercedes benz, right?
Who was using cummins?

[Tyania]

Ok so I think maybe Blue Bird uses cummins??? Do I win a prize if I get it right?

It is soooo easy to sound dumb on this forum...

Example: Ward Body Works became Amtran, was absorbed by Navistar International who later changed the name to IC Corp which has now changed to IC Bus. At some point the buses were refered to as international and now IC. They use a variety of engines makes with their own names (not to mention model names) sometimes by the same. I am not even sure I have that straight and that is just a piece of one companies name game involved in school bus corporate monopoly.

It's gnarley and I am trying to keep up with everyone by doing wikipedia crash course so hang in there and be patient with me everyone....
You are all so helpful.

[cowlitzcoach]

If you have to purchase 2004 and newer I would not go any newer than 2006. When the new clean air rules came into play in model year 2007 everything changed.

I am a big fan of IC buses. Personally I think they are some of the better buses built. But you couldn't give me a fleet of IC buses if they were equipped with the VT-365, the MaxxForce7 engine, or the MaxxForceDT engine. As a former employee of an IC bus dealer I saw too many of them showing up for warranty repairs or requiring parts for major repairs long before they should have needed anything beyond an oil and filter change.

If you find a bus with the DT466E you will be getting one of the best engines ever built with the addition of electronic controls to make it run better and use less fuel. The DT466E will only be found in IC CE, IC FE, or IC RE buses.

I would stay away from the Cat and Mercedes-Benz engines not because they are bad engines but because finding anyone who can work on them is difficult and very expensive.

The M-B engine will only be found in Thomas C2 and Saf-T-Liner. You will also find Cat and Cummins power in Thomas buses.

Blue Bird was owned at one time by Volvo. As a consequence the Vision model uses a lot of Volvo sourced parts and pieces. I am not aware of any that had Volvo power but the diesel powered buses had both Cat and Cummins engines.

Cummins stopped production of the 8.3L ISC because it overlapped the power and torque the ISB below it and the ISL above it. Once the 2007 regulations came into play very few operators purchased them after 2007 as the engines never got warm enough to work the emissions systems and most of them became garage queens. An ISB working really hard to do the same work the ISC was doing while just loafing along worked out much better for the operators.

I suppose what I would recommend is that you find a 2004-2006 model year bus in order to find your optimal power package.

I would stay away from the early models of the Thomas C2. That was the first fully multi-plexed bus and Thomas has had a lot of teething problems with them.

I would also stay away from the Blue Bird Vision as it is known as the no-vision bus. I know some who actually like the driver's position but most drivers I have asked really do not like them.

I hope this helps.

[jctrembly]

Originally Posted by cowlitzcoach

If you have to purchase 2004 and newer I would not go any newer than 2006. When the new clean air rules came into play in model year 2007 everything changed.

Well said with your whole post. This forum is a great asset for all of us.

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[cadillackid]

this thread seems to have some of the best one-stop-shop info ive seen without scouring.. esp since very soon in the next couple years all of the pre-emission busses will be mostly gone.. this thread maybe should become a sticky somewhere..

ive seen cummins in some of the frieghtliner chassis busses.. they seem rare.. or the auction listings are marked wrong... im only going on what the listings say as i dont have enough experience with thomas busses personally to know if they truly used 5.9s or not .. i do at some point plan to acquire a Safe-T-Liner C2 just because I DIG its modern looks..
-Christopher

[Tyania]

Originally Posted by cowlitzcoach

I hope this helps.

Absolutely.

Originally Posted by cadillackid

this thread seems to have some of the best one-stop-shop info ive seen without scouring..
-Christopher

Agreed. You all really came through for me and for anyone needing this info.

[Tyania]

Well this info has been great but it has narrowed down my already narrow search... And while I have been researching all the engines you all mentioned, I noticed that there have been some gas engines in the mix. (I had thought that only van cutaways had gas options.)

Any gas engines that I should keep my eyes out for? Note that I am not restricted to post 2004 if I get a gas engine since as long as long as it is not so old that it is structurally or mechanically unsound, it could work!

Would love your opinions since I am ready to buy and need it to do it soon. Could use the extra options to open the possibililties.