Low Coolant Alert

[michaeldterry]

Two days ago, the owners of Evangeline's new storage home called to ask if I could move the bus to another part of the lot temporarily as they are in the process of running conduit under the concrete tarmac to install an additional 12 Jamestown Advanced 50 Amp power hook-ups! Of course, I had no problem accomodating this request and went right to the bus lot to get Evangeline disconnected from shore power, cranked, warmed up and moved. When I went to crank her - nothing - just a barely audible click. My initial assumption was that I had set the inverters wrong and had allowed the chassis batteries to discharge. However, it had been less than a week since I "exercised" her with a day trip to Forsyth County to watch the indoor drumline that my son designs for and teaches in a competition (and the bus operated flawlessly).

I cranked the generator with no problem, forced the inverters to bulk charge, tried the "battery boost" feature on the dash - all to no avail. On a whim, I went to the back of the bus and opened the engine compartment. I used the rear start panel and she cranked right up! I went back up front and looked at the DDEC only to notice that there was a "Low Coolant Alert" at 0% and the Check Engine (yellow) and Stop Engine (red) lights were both illuminated! I double checked around the exterior of the bus to make sure that there were no "puddles" indicating a coolant/radiator leak. The concrete was dry with no evidence of a prior leak event (no stains). I moved the bus to another part of the lot as requested, but shut her down immediately to make sure that I didn't make things worse. I'm now at a loss for what to do to resolve this latest issue. Obviously, I want to take the bus to an appropriate Detroit Diesel Service Center to have the issue diagnosed/resolved, but I'm scared to drive it any distance with the stop engine light lit!

I'm literally between a rock and a pile of doo-doo! I'm hoping against hope that I simply have a bad sensor, but don't know how to verify that. Is my only recourse a road service call from someone like W.W. Williams? I've got to act on this immediately because we have a hard wired commitment in the bus on April 6th!

Any advice/guidance/help from the POG braintrust will be most appreciated! (Remember to speak slowly and use small words - you're not dealing with the sharpest tool in the drawer)!

[garyde]

Hi Michael. Did you check the site glass on your coolant reservoir in the back engine compartment. If it shows full, then your sensor is probaby the culprit. I believe you can wire around it but I don't know if just tieing the sensor wire together will do it.

[truk4u]

Michael,

The inverters have no charge function for the chassis batteries unless Vantare is different then most. Do you have a seperate charger for the chassis batteries? Your chassis batteries were not low, you started it manually. Are you certain the 12 and 24 volt cutoffs in the engine compartment are on. When you got it running with the manual start, did you have the ignition key in the on position? Strange things may happen when starting manually with the ignition on. It almost sounds like the check engine and shut down lights were in the startup test mode that would normally go out as soon as the engine starts. Did you check the site glass on the coolant tank? The low coolant sensor can be bypassed.

[sawdust_128]

Correct. Vantare' did not modify to charge chasssis batteries with inverters.

Michael,

I agree with others, check the coolant level in the expansion tank. It may be that as a result of your last run, you heated the coolant and expanded the volume of coolant into the resevoir. You simultaneously lost some coolant. On cooling, the contraction of the coolant will cause the level to fall below the sight glass and the sensor. I had this happen and it would start, but would only run for seconds and shut down.

Another related question. Last summer when everyone was discussing the bad shape of the coolant lines going to and from the expansion tank, did you check/replace them as well?

[Jon Wehrenberg]

Based on Michael's description the problem may go beyond the coolant level.

I'm just guessing here. The coolant level sensor is the one that can be jumped. Put a paper clip or something between the terminals on the connector and if it is a bad sensor (assuming the coolant is above the sensor probe) that alert should go away. The coolant level sensor is one of the ones that not only shows a check engine, it also will do an engine shut down.

The problem with not being able to start from the front, if not related to the coolant sensor or level could be in the selector switch on the rear box, or at any other switch point within the start circuit including the key switch. To find out the root cause correct the coolant level sensor issue first.

[flyu2there]

Have you pulled the oil dipstick? Should the site glass show coolant I would guess it is some kind of an electrical issue, if it is mt and it is not on the ground.....look at the engine oil quantity.

[Orren Zook]

Michael,

In another thread you mentioned a problem with the keyless entry, the anti-theft portion of that will prevent the bus from starting with the key but will allow engine start from the rear panel, but then, unfortunately most normal "key on" functions won't or don't work - auto leveling, dash gauges, etc. I'd take a look at the relay controlling that first, just because it's easy to do.

[michaeldterry]

Gentlemen - I've accumulated all your helpful replies and will be going out to the bus either this evening or tomorrow morning to follow your collective troubleshooting instructions! I'll let you know what I find and am able to accomplish as soon as I get back. Might I assume that if I see coolant in the sight glass and check the dip stick for level, that jumpering the sensor will enable me to safely move the bus to a qualified Detroit Diesel certified shop to get a resolution (i.e. - replace sensor)?

[Jon Wehrenberg]

The sensor just threads in. If jumpering it solves the problem you can replace it at your leisure. Orren may be on to something.

[michaeldterry]

The sensor just threads in. If jumpering it solves the problem you can replace it at your leisure. Orren may be on to something.

That's encouraging! Here's hoping!!!