New Bus! New Problems...

[frankenboom]

Hello all,

I've been lurking here awhile but I've never posted. Now that I've bought a bus, I finally have something to talk about! I'm new to this whole thing, and while I would say I'm mechanically minded (currently studying mechanical / aerospace engineering) I know very little about buses.

Apologies for the long post, but if anyone is knowledgable about these problems, the help (and excessive detail - like you're talking to a five year old!) would be greatly appreciated!

I recently purchased a 1998 RE Thomas bus - school bus everything except transit windows.
It's got an Mt643 tranny and the famed Cummins 8.3.
It does have 375,000 miles on it, but no biggie .

On the drive home, it mostly behaved. Steering was tight, power was good, and brakes were strong. However, there were some problems.

1) Trans temp, speedo/miles counter gauges do not work at all.

2) tach seemed inaccurate - RPMs were well above 4k at some points (ie way over the scale on the gauge)

3) Intermittent power loss on the road (near the beginning of the drive, happened twice, no problems later on).

This was also paired with a very noisy accelerator that made wooshing sounds (air accelerator? what even is that?)

On idle, the rpms also periodically pulse - the engine audibly gets faster for a few seconds, then slows back down for a few seconds, etc. This is paired with dimming of the lights as the engine revs.

Hopefully this is just some problem with the pedal itself, but I know other culprits include the sensor in the little bulge under the gas pedal, clogged fuel lines / filters.

4) a Dented rim. How much to replace?

5) This is the most worrisome. There is green fluid leaking from the engine. (where? It seems to me like the seam in the picture attached.) From what I've heard, this is coolant. Could this just be a bad seal and a quick fix?

I did not notice this leak on the way down or the day we parked it (kinda cold weather), but today, the outdoor temperature rose and it was dripping quite quickly. It slowed and eventually nearly stopped as the day went on, lost maybe a few ounces of liquid in a few hours.

6) Transmission fluid dipstick does not have perfectly pink fluid. There seems to be some black in it, but that could just be from the dipstick tube being dirty. also, how should it smell? Mine is somewhat bitter - smelling, maybe burnt. \

7) Many components in the engine compartment are covered in oil, but I can't see well enough to find a leak (washing it off would help) but I don't see any active leaks.


I know I have to replace filters, and my batteries' voltage is also below 12.0 v., (won't start, tested voltage w multimeter both on bats and starter, not a grounding problem) so those have to be replaced as well.

Again, thanks for all the help! I'm new to this and not very knowledgeable about engines, so extra detail would be appreciated!

[miltruckman]

That is the timing gear cover. Antifreeze should not leak from there. But it could leak oil.

How did the oil look after driving the bus? Was it still looking like oil?

Not milky?

Bill

[frankenboom]

yea, I checked the oil and all seemed well. That being said, if the amount of coolant or antifreeze leaking into the oil was small, it may not be noticeable.

I'm assuming the antifreeze is put in the coolant, and that's what gives it the bright green color?

Tomorrow, I will post pictures of the dipstick and the area that looks like it's leaking.

[turf]

I circled the water pump for you. a loosened bolt or faulty pump could be the culprit. water pumps are cheap. replace the belt, water pump, fuel filters, air filter, burn off all the old fuel, get some fuel system cleaner and fresh diesel in the tank.

then see how it is. you should rule out filters and fuel before digging into any power problems.

you probably need to find a bad ground on the gauges if they are all out. that will require a bit of investigative panel removal.

transmission fluid will burn, and smell burnt when its been overheated. all you can do is drain and refill. if the new fluid goes bad quickly, your trans may be in poor shape. it does take 2 full drainings of the trans to get all the the fluid out of the torque converter.

good luck

[frankenboom]

Thanks so much! That gives me a lot to go off of.
Once I get a chance to do these things, I'll let you know how it all goes.

[cowlitzcoach]

3) Intermittent power loss: If the bus hasn't been run in a while you are most probably having issues due to old fuel and clogged filters. Before you start doing anything else you do need to replace all of your fuel filters, dump some fuel conditioner into the tank, and burn off whatever was in the tank when you purchased it. A lot of drivability issues are related to clean fuel or the lack thereof.

4) Dented rim? You don't specify where the dent is and how bad it is. The worst case is you will have to change the rim. Before you go shopping for a new rim you need to know if it is the older style lug centered wheel that has chamfered lug nuts with a thimble and lug nut on the duals or if you have the newer style hub centered wheel that has a flat mounting surface with lug nuts with a built in washer. A used wheel should cost in the neighborhood of $35.00-$100.00 depending on what kind of wheel you decide to get. Shiny aluminum might even cost upwards of $400.00 per wheel.

7) Dirty engine compartment: You need to clean everything off so that there is no grease, black gunk, or what have you anywhere on the engine or in the engine compartment. First off, all of that black gunk creates a fire hazard. Second, it will hide where your leaks are originating. Once you determine where the leaks are occurring it will then lead to a repair solution that could be as easy as re-torqueing the bolts that hold the pan up, the front cover on, and the valve covers down.

Good luck.

[superdave]

how far /long did you drive, it would take an hour before the tranny temp gauge starts to rise, mine goes to about 180. do you have a hydraulic drivin cooling fan in front of the radiator? feel under the fan motor for oil and look on the inside of the frame facing the radiator for oil, if its covered in oil your fan motor is leaking. great bus b t w, just needs a little love. we need some pics, good luck

[frankenboom]

Thanks, guys for all the help! What a great community!

I'll get to these things when I can and come back with updates as I go.

[frankenboom]

Originally Posted by superdave

how far /long did you drive, it would take an hour before the tranny temp gauge starts to rise, mine goes to about 180. do you have a hydraulic drivin cooling fan in front of the radiator? feel under the fan motor for oil and look on the inside of the frame facing the radiator for oil, if its covered in oil your fan motor is leaking. great bus b t w, just needs a little love. we need some pics, good luck

Hey!

We drove for about an hour on the highway with no perceptible change in the trans temp gauge. Some of our gauges work, others don't. I'll check out wiring as well as I can.

No large amounts of oil that I could tell around the fan or radiator, but that being said, I'm not sure if the fan is hydraulic - driven.

Attached is a pic of the bus!

*edit - not sure why the picture is flipped. Tried uploading it both upright and rotated, no change*

[superdave]

that's a nice white bus, great job. do any of them windows open?

[cadillackid]

great lookin bus, definitely what others have said, degrease the engine, old diesels often drip a couple drops of black oil here and there on the ground.. ive driven a total of 20,000 miles in both my busses collectively over the last year.. leaving a couple drops of oil on the ground here and there without issues..

Cooland can come from many places.. your coolant circulates through your heaters, the radiator, and also inside the engine block.. the water pump as pictured is often a source for a coolant leak.. when water pumps wear out the bearings get loose and the seal can start to leak around the center pulley.. many water pumps have a little tiny hole in the body right below the pulley.. its called a weep hole.. if your pump is wearing out, you will see green coolant start to drip from that hole.. that indicates the water pump seal is bad and the pump needs replaced.

there are often hose connections near or around the water pump as well.. hose clamps can become loose when a bus sits, or from use, sometimes ytou can see green coolant weeping around the edges of hoses , and the clamps just need a quick 1/4 turn on the bolts.. usually a 1/4" or 5/16" socket fitting.

also fluids run downhill, so when you see a leak, try and look up higher and higher from where you see it, till you dont see the wet any longer.. this is often your source.

a good time to search for coolant leaks is right after driving, start the bus, drive it for a while till its fully warmed up, bring it home, turn the engine Off, then go look under the hood for your coolant leak. the cooling system stays pressurized for a while after you shut the engine off, so right after driving is a great time to track that leak down.. the engine itself will be hot.. a good compact LED flashlight with a focused beam is a great tool for tracking a pesky leak down. LED flashlights are bright enough that it will make wet spots look real shiny and help you go at it.

-Christopher

[turf]

my motor is the cummins 5,9. and when changing belts, i spotted a similar leak. the new water pump was cheaper than the belt. the belt was $65, the waterpump $40.

in hind sight, my leak was from a loosened bolt. but the whole pump got replaced because of dripping from the same spot you marked.