School Bus Conversion Resources

School Bus Conversion Resources (
-   International | Navistar Drivetrain (
-   -   DT466E Inframe Rebuild (

Meddle 10-29-2018 09:04 PM

DT466E Inframe Rebuild
I don't post often but this has to be shared. I have owned my bus for over 2 years now. It has a DT466E. I have put very few miles on it because there were things that needed to be dealt with. I have driven it about every other month. Recently, I took the bus out for a hill run / test and it failed miserably. By the volume of coolant in my oil, I believe I blew 1 or more cylinder liner seals. So now I am doing an in-frame rebuild. This where it gets fun. My bus is parked on the street in front of my house. The drivers side wheels are on rough asphalt. The door side wheels and under the bus is crushed mine rock. A cherry picker will not work for pulling the head. Besides, I'm trying to do this under the radar. Since it is parked on the street, I would prefer the neighbors not know that the engine is torn apart and the bus is immobile. I took some measurements and found that once the valve cover, injectors and rocker assembly are removed I have about 7" of clearance between the top of the head and the opening thru the firewall. I fabricated a low profile bracket to bolt to the head. Then I positioned a furniture moving dolly inside the bus directly behind the engine and as close as I could to the engine. On the dolly I stacked a couple of 4x6s crosswise and used woodworking clamps to secure them in place on the dolly. The last item was a 13 foot piece of 1.5" box tube. It attached to a central point on the head bracket and rested on the 4x6s as a pivot point. Once i broke the head loose with a pry bar, all I had to do was apply about 40 lbs of pressure to my 13 foot lever and the head lifted right up. I guess I judged the balance point of the head pretty well because when lifted it did not tilt at all. Once the head was clear of the block I just rolled the whole thing towards the rear of the bus. Bam!! Head inside the bus. One man. No cherry picker! It will be a 2 man operation to re-install the
head. I will need someone to operate the lever while I guide the head into place. That's all for now. This will be an ongoing thread. I will share my experience as I find time.

Iceni John 10-29-2018 09:13 PM

Did you overheat it? What caused the liner seals to fail? If you replace them now, what's to prevent this happening again?


Meddle 10-29-2018 09:27 PM

I'm thinking the seals were old and brittle. I already disassembled the oil cooler. The seals in it had almost no elasticity. They cracked when I removed them. I'm guessing the cylinder seals will be the same. I will know this weekend when I pull them. As far as what really caused it, it doesn't really matter. When putting this much time and money into something, I'm rebuilding / replacing pretty much everything.

Meddle 10-29-2018 09:30 PM

Including the radiator.

cadillackid 10-29-2018 09:36 PM

its not uncommon for an engine that sits a lot to end up with dried seals.. some guys drop the pan and pressurize the system to see where the coolant is coming from.. but since you have the head off may as well pull the liners and piston / ring it.. since you are In-framing you will likely want to have that head worked.. make sure the injector cups arent the source of the leak and have the head tested and planed if needbe..

when you get the liners out check them for cavitation, that can be the source of failed seals. and symptoims of past poor coolant maintenance.. (you'll replace all the coolant and add correct SCA.. or you can go with a polyorganic synthetic coolant like Amsoil's High performance coolant and not have to worry about SCA additives)..

Love your jig for pulling the head and taking it Inside! great stuff!

Meddle 10-29-2018 09:45 PM

Thanks for the compliment Christopher. I was using the Navistar recomennded Fleetguard coolant, no additives required per Navistar.

Meddle 10-29-2018 09:52 PM

I've put only a couple hundred miles on the bus. The one thing I know is when I bought the bus, it had green coolant in it. It will be interesting to see if I have any cavitation damage. Hopefully if present it will be contained to the cylinder liners. To tell the truth, I'm not worried. I'm pretty sure it's gonna be a standard rebuild. Knock on wood!!

FamilyCircus 10-29-2018 11:08 PM

5 Attachment(s)
I am doing the same thing to my DT466E, this one was overheated I assume in a previous life and the #6 line seals failed.

I work at a Cummins shop and have spoke to a few techs that came from Navistar and they all tell me the same thing, if these over heat even a little #6 goes first. My 80 yr old dad and I removed the head together by hand.

This is a very easy engine to work on, at least it is in my type D bus.

Here are some pictures of the damage. #6 and #5 pistons and liners.

cadillackid 10-30-2018 05:14 AM


Originally Posted by Meddle (Post 296500)
I've put only a couple hundred miles on the bus. The one thing I know is when I bought the bus, it had green coolant in it. It will be interesting to see if I have any cavitation damage. Hopefully if present it will be contained to the cylinder liners. To tell the truth, I'm not worried. I'm pretty sure it's gonna be a standard rebuild. Knock on wood!!

The coolant you are using now is the right stuff. Green coolant is often neglected and thatís where issues arise. Iíve never seen block damage , just the liners. As family circus mentioned it doesnít take much to damage these seals. Running the temp up to 230-240 is sometimes all it takes to make those seals brittle .. an air bubble trapped after a coolant loss, bad fan clutch etc in its past life.

On these the computer hard stores the miles and hours of any overheats or low oil conditions in its life. I realize most arebtvscan tool geeks but if anyone looking to buy a bus has access to a reader itís a good idea to scan it.

Rent the liner removal tool if you can and be extra careful to get them installed precisely.

Iím assuming you are also going to replace your bearings since youíll be in the pan to pull the pistons.

Once you complete this youíll be ready to roll for a good long time.


Meddle 11-01-2018 08:50 PM

Yes, I'm going to replace the main and rod bearings. I'm going to try to remove the liners from below using a brass drift punch. If that doesn't work I will just fabricate a puller. Since I had to pull the harmonic balancer to get to the bolts for the oil pump pickup tube, I'm going to check out the oil pump and replace seal since it's accessible. I didn't get the engine drained until a week after the catastrophe. Under the valve cover was pretty ugly but it all just wiped out using a lot of paper towels. When I pulled the pan, the bottom end looked pristine. Just a little sludge in the bottom of the pan. I just want to make sure the oil pump is all within spec. I'm going to be buying my rebuild kit soon. Does anyone out there have some professional experience with aftermarket rebuild kit vs Navistar OEM kit? I think I'm leaning towards the OEM kit, just because. Another question. Navistar says use new bolts on head, rod and main bearings. A lot of what I've watched and read says they can be reused with no adverse affect. Anyone out there with reused bolts and a good amount of miles on them? Thanks in advance for any input!

All times are GMT -5. The time now is 10:50 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.