This topic contains 21 replies, has 5 voices, and was last updated by Mike 8 months, 1 week ago.
- January 18, 2014 at 4:56 pm #25752
Has anybody had any problems with Thomas school buses?
I want to compare notes and share solutions that our shop has discovered over the years.
Just to help each other out and save time .
This post is not intended to write negatively about Thomas buses….it’s meant to make life easier for school bus techs 🙂February 5, 2014 at 7:32 am #29029
I would be glad to try to help you if there is a particular area you are talking about.I am foreman of a school bus shop of 44 shops the state of S.C. operates.We have roughly 5600 buses across the state that are state owned and operated.We have used Thomas busses from 1992 to current.We have just about every model from type b -type d.We have had numerous recalls over the years and repairs to trouble areas.We aslo have had numerous PSB ,which I call problems the manufacturer does not want to recognize. I have been employed for 27years with the state,so I have been around a couple days.February 7, 2014 at 10:08 am #29035
Great to have you here Roger. I want to compare notes with you on Thomas or IC repair solutions that you have experienced. You are probably familiar with the C2 issues from the past and the Mercedes MBE 900 engines ? We can start a support thread right here with solutions and ideas to help out other school bus mechanics .Post anything you want right here.February 7, 2014 at 10:31 am #29036
Roger, We have a 2005 Freightliner school bus with a MBE 900 Mercedes that runs at 150 degrees and climbs up to 175 degrees running a grade then drops back down when coasting and on the flats .
The ambient temperature is -20 Celsius . COLD! The radiator shutters and winter front are closed at all times…the engine does not get up to the thermostat opening temperature along with the rad shutters. Thermostats have been replaced.
Viscous Fan Hub?
With the engine off the Viscous fan hub can be turned by hand. However with the engine running it has enough drag to create a lot of COLD air movement across the engine. Looking at replacing the viscous fan hub (original) thinking it has too much drag . This is the only piece of the puzzle that is effecting the cold running condition.
Have you experienced this cold running condition in your part of the country?
The long coolant hose routing and floor heaters in the cab increase the load on the heating system but the engine should be able to keep up.February 10, 2014 at 9:02 pm #29041
Hello John as of almost a year now I have been working at school buses with a private contractor.( The forestry industry here crapped out and the bushmechanic was forced to move on). We have about 70 buses in the fleet and only four of them are C2 ‘s, the majority are Blue Bird Visions. We have one thomas that’s an air ride and it wears out rear tires quickly. Well they don’t wear out but they get all knoby and then they kick up a hell of a racket on the road. It’s not an inflation issue as we have adjusted constantly to remedy the problem to no avail. Have you seen this problem before? Any help would be appreciated.February 17, 2014 at 10:06 am #29056
The 2005 freightliner problem you discussed .I believe I would replace the fan clutch.We don’t have that kind of problem here it does not get cold enough here.I have talked to a friend of mine in Oregon he said they have to add coolant heaters to there on the road vehicles in that area to get operating temperature up.February 17, 2014 at 10:25 am #29058
Hi Will, glad you hear you changed over to school buses. They will keep you busy. I have the exact same problem with three 2009 C2s. The tires get badly cupped and only last 10 to 12 months. We laser aligned the buses and reduced tire pressure because of the rough ride even with air ride suspension.
The Michelin man suggested rotating them when they start to cup to extend tire life. Other than that the dealer has not come up with a solution. Part of the problem with the rough ride I believe is the buses in question are all wheel chair units and don’t have enough weight(riders) to absorb the 23,000 lb drive axle.
Both recaps or new tires do not make a difference with the cupping condition.February 17, 2014 at 10:31 am #29059
Roger, we changed the viscous fan hub primarily because it was leaking and the bi-metal spring was loose. It has made a difference but not a big one. A diesel coolant heater would be a nice addition. The weather has warmed up this week so the problem is on the back burner right now. I would love to install a Horton fan clutch on it but it doesn’t make sense when it came with the viscous hub from the OEM. Thanks for your reply.March 2, 2014 at 8:46 pm #29089
We have installed Webasto aux. heaters on all our diesel units since 2004. That is the only way we can keep operating temps up. Last summer we purchased 12 Bluebird Vision propane units and so far the drivers love the heating of these bus without aux heaters. They do not need to be plugged in at night to start in the morning the only downfall we have seen so far is our on-site filling station nozzle has issues in the extreme cold. We are working with the propane supplier on this and will update. Mileage is 4-6 mpg depending on driver and routeMarch 2, 2014 at 8:57 pm #29090
Tire wear is something we all deal with and over the years have spent a lot of time looking at alignments and tire tread patterns. I our fleet we have found running a closed shoulder tire has given us better wear. We are using virgin tires and recaps and have narrowed it down to the Fuel tech drive tread pattern from Bandag. Even with lots of snow we try to stay away from a real aggressive lug to reduce cupping. Years ago a tire rep told me this is caused by torque flex of the diesel hp engines coupled with the auto transmissions in todays buses. We know the drivers foot controls that point. Just some thoughtsMarch 3, 2014 at 12:53 am #29091
The Webasto heaters have been very unreliable maybe because they don’t get used enough in the warmer months? The circuit board fails and they come at a hefty price! Since we started using Espars in the Internationals we’ve had good results. I road tested a Vision some time ago ..they run at a very high RPM. approx. 4500? Interesting to hear about the cold starts with propane. The infrastructure (fueling station) must be costly?
Thanks for the tire info…I leave the tread choice to our recap provider. I’ll have to ask the salesman more details on that one.March 3, 2014 at 1:34 pm #29094
We actually got our propane supplier to help with the cost so it was not that bad.
Have to look at the espars once and see how pricing compares. What model of the webasto do you runMarch 3, 2014 at 1:36 pm #29095
John what wattage block heaters do you run in the DT466E engines up there?March 3, 2014 at 8:20 pm #29102
Our block heaters are 1250 Watts.
The Webastos we use are a TS-17 Thermo Top C . To buy the circuit board you have to include the combustion chamber which explains the cost.
The Espars are an E-Guardian made for school buses. They are actually a little more costly than the Webastos ($200) in my part of the country.March 4, 2014 at 7:42 am #29106
WE have had many problems with the TS-17 also, just don’t last in our conditions. On our early FS65″s we converted to the Thermo 90 unit, it has add. BTU’s for added comfort for interior warmth. Only downfall is the burner cup design which requires servicing after every season. On all new units and units where the TS17 units fail we update to the scholastic unit offered for school buses. It works great drivers love them extra warm in the winter. Our 2013 Visions have seen an issue of not auto starting with the timers in the extreme cold (below zero) Last year they worked all season. I believe it may be a power supply issues, will keep you updated