How old is too old with a diesel?

[Laeka56]

Thanks for all of the help you guys have given me this year! Looking at another bus; 1999 Thomas Vista Bluebird, 6 window w/chair lift, flat front, Cummins ISB diesel engine (190-230 hp), Allison transmission, 200,000 miles. That's all I know for know. Looks clean in the pics. They are asking $4K. I'm wondering at what point do I say it's all just too old even if it's a diesel? What questions should I be asking at this point? Thanks!!

[Dog Rescuer]

I bought a 2000 International with 297,000 miles on a 7.3L V8 turbo 210HP diesel engine - and I have driven about 40K miles in the last year and a half - across country and up and down mountain passes.
I don't think age / mileage is as important as well maintained. If the bus was taken care of over the years - it will keep on going.

[o1marc]

You have the 5.9 with likely an AT545. 200k is not too much on a bus that has been regularly maintained properly. Your drivetrain, I suspect, would need rebuild sooner than some other models,but with proper maintenance and rebuild schedule most could see 1 million miles. So hit's hard to tell how many miles is too many just going by the odometer. If it runs well, doesn't burn a lot of oil, then run it till it does.

[OrionsComfortBus]

I would be looking at parts availability, You should not have issues with that. Does it have blow-by? If so is it just little puffs or is it like a constant cloud? That should give you a idea if a rebuild is necessary sooner than later.

Age: As far as I know, ANY engine can be rebuilt. It just depends on how much money it will cost, manufacture of parts, ect.

Dont forget Seafoam. That stuff is amazing in my book. I was getting 33 gallons burned in a round trip from Lytle Tx to Austin and back. After Seafoam its down to about 18 gallons for the same round trip. I dumped a gallon of Seafoam in the fuel tank at about 1/4 tank and a quart in the crankcase. Made the odd noises go away and the little engine seems to have more power now than before. Seafoam has a channel on youtube for tips.

Hope this helps.

[cadillackid]

Originally Posted by OrionsComfortBus

I would be looking at parts availability, You should not have issues with that. Does it have blow-by? If so is it just little puffs or is it like a constant cloud? That should give you a idea if a rebuild is necessary sooner than later.

Age: As far as I know, ANY engine can be rebuilt. It just depends on how much money it will cost, manufacture of parts, ect.

Dont forget Seafoam. That stuff is amazing in my book. I was getting 33 gallons burned in a round trip from Lytle Tx to Austin and back. After Seafoam its down to about 18 gallons for the same round trip. I dumped a gallon of Seafoam in the fuel tank at about 1/4 tank and a quart in the crankcase. Made the odd noises go away and the little engine seems to have more power now than before. Seafoam has a channel on youtube for tips.

Hope this helps.

what seafoam products did you use? i should do that on my DTA360.. its a relatively new engine (105k miles) but I should give it a shot anyway..
-Christopher

[EastCoastCB]

Originally Posted by o1marc

You have the 5.9 with likely an AT545. 200k is not too much on a bus that has been regularly maintained properly. Your drivetrain, I suspect, would need rebuild sooner than some other models,but with proper maintenance and rebuild schedule most could see 1 million miles. So hit's hard to tell how many miles is too many just going by the odometer. If it runs well, doesn't burn a lot of oil, then run it till it does.

I'd be very surprised if many school buses hit 500k, let alone a million. These are medium duty engines except for a lot of the Crowns.
This is also "severe" duty, so not as easy as a half million highway/interstate miles. this is 90% stop and go.
MOST buses are getting pretty tired by 300-400k. Most folks don't put many miles on em so it doesn't matter.

[OrionsComfortBus]

Originally Posted by cadillackid

what seafoam products did you use? i should do that on my DTA360.. its a relatively new engine (105k miles) but I should give it a shot anyway..
-Christopher

I used the white canister Seafoam. Buying a gallon is more economical than 8 16 oz cans. Seafoam to oil ratio is 1 - 1.5 oz per qt of engine oil. A little extra won't hurt it . I recommend watching the tips on YouTube Seafoam channel.

[EastCoastCB]

Originally Posted by OrionsComfortBus

I used the white canister Seafoam. Buying a gallon is more economical than 8 16 oz cans. Seafoam to oil ratio is 1 - 1.5 oz per qt of engine oil. A little extra won't hurt it . I recommend watching the tips on YouTube Seafoam channel.

Josh LOVES Seafoam!