Cooling system woes

[natedlee]

I'm on the road in my 1998 Blue Bird TC2000 W/ Cummins 5.9 12v and I'm running into a couple issues.

1) My fan clutch isn't being triggered: so I assume a temp sensor is bad.
- I know the clutch works bc I tore down the front to replace it and found the wires had been ripped out.
- my dash temp gauge works, so I'm assuming there are 2 temp gauges?

2) Coolant leak: I suspect this red cylinder thing, but I'm not sure what it is. I noticed some coolant dripping today and found that this red cylinder thing next to my front steps (right if engine) is somehow involved. It's wet on top, which seems strange. Is it part of a heating system that was taken out?

3) My coolant dashlight is always on: This started after I took everything out for the fan clutch. At first it was inconsistent, but now it's solidly on. Coolant reservoir is totally full. I've ignored this light, but I'm unsure if it's involved with the above stuff.

We're planning to drive back home from CO to MD Thur so wasn't sure is I was heading into danger. Thanks!

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[Iceni John]

The red thing is a cylinder of ether for a Quick Start ether injection system, for better starting in cold weather. You may have a button or switch near the start key for triggering it if needed. Unless you live somewhere really cold, you probably won't need it. I have this system on my bus (it was originally in service in the California Sierras), but I don't plan on buying another cylinder of ether for it - a block heater is a better way to start in cold weather.

Your coolant leak may be unrelated to the Quick Start system, unless it's leaking from the QS's temperature switch which is probably somewhere in the engine block, maybe near the thermostat housing.

Sometimes the Low Coolant Level sensor in the surge tank needs to be cleaned, and sometimes they fail altogether. It's probably a sensor with two wires, near the bottom of the surge tank. Drain the coolant, take it out and clean it, then check it - replace it if it doesn't work right because it's important! Its second wire is a ground: check every ground connection on the whole bus, because they can give you false alarms (or worse).

John

 

[PNW_Steve]

John,

You are a wealth of good information.

Thank you.

 

[Brad_SwiftFur]

Second on the ether tank. I'd remove it. The coolant has to be coming from somewhere, you'll have to track down the leak and go from there.

The low coolant light will be an important fix as not only will you need to know if the coolant really is low (or not) but it often ties into other systems and on some computers they will not go into normal mode (when warmed up); they will remain in "warm up" mode indefinitely. This can mess with emissions and more importantly, fuel economy.

 

[turf]

the leak looks like the area of the water pump. i'd check those bolts for being loose. tighten all hose clamps. have you bled the air out of the system? there is a little hose and valve near the radiator cap to bleed the air out until you get a steady flow of coolant. air pockets can keep the water from circulating well.

 

[2kool4skool]

Yes, check everywhere: Rad cap, all bolts, all hoses and clamps. I had a small leak that after a few months turned out to be the rad. itself. Had to pull it, took to an expert to verify. I got a hand pressure set up to pump up the cooling system so I could check it without running every time to build pressure. Here's the bleed instr.

 

[natedlee]

Yes, check everywhere: Rad cap, all bolts, all hoses and clamps. I had a small leak that after a few months turned out to be the rad. itself. Had to pull it, took to an expert to verify. I got a hand pressure set up to pump up the cooling system so I could check it without running every time to build pressure. Here's the bleed instr.

It doesn't appear I have the bleeder valve. Jk just the overflow hose and the green hose.

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[turf]

i'd almost bet you that one of those tubes in both pictures is your bleeder tube. look for that brass valve in the diagram. the tube should be end within a foot or so of the radiator cap.

 

[cadillackid]

I dont have a cummins but on my red bus the bleeder valve is up high on one of the heater hoses a couple feet from the engine.

-Christopher

 

[2kool4skool]

Mine is, looking from the front, to the left side of the rad. cap. It was tucked back in there and hiding Also, you have no sight glass on the deaeration tank. Easy to replace.

Of the 2 hoses in your pic, the hard one is the bleed, that other is a washer hose.

 

[natedlee]

So I had a mobile mechanic out and he explained a TON about my system to me. The leak was coming from the heater hoses going into the right side of the bus to heat the cab. I have 2 shutoff valves and turned them off, removing the problem until I can fix it. As expected he was given the wrong given the incorrect temp sensor so we didn't replace that. However, I'll be fine for this trip I think. I guess.

Still can't find a bleeder hose. Never saw it when I pulled the front out to fix the fan clutch either.


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[natedlee]

Also - my fixed fan clutch wasn't being triggered bc when we reconnected the clutch harness it pushed the hot wire out of the plastic housing. Put it back together yesterday and fan engages when engine reaches temp. Huzzah!!


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