Bus Shutdown on the 40 120 degrees

Hi folks, I am new to the POG, i have been reading all the posts new and old but this is my first post. I purchased a 1992 Prevost Bus in AZ and it shutdown about an hour from where I picked it up. I had to have it towed and stored for a few day till i can get to it to start troubleshooting. I was traveling up the grade out of needles and the coolant temp got almost to 220. I know that is too high, the Bus needs a complete flush of all fluids which i plan to do once I get it home to Los Angeles. I felt the power drop off, then the tack dropped to zero and i got onto the shoulder. Seems to me if it was a sensor shutdown it should have reset itself once things cooled, but it didn't. I put a jump box on the engine and it turns over fine, just no crank from the Key or switch in the back. I have all dash lights etc, just won't crank. An interesting thing i noticed, is I have no red light on the shifter. Hopefully this is a clue for someone. Any help would be appreciated.


1992 Prevost XL 102, Country Coach

8V92TA Engine

Allison 5 Speed Automatic
Model: HT-755CR,

When it shut down was it in gear? If it was u have to manually get it back into neutral .

If so on the pass side of the trans is the shift linkage. 1 click up from all the way down is neutral. Do not get under it without a support stand or 2 or 3 considering u don't know the bus or the ground it sits on.

Great suggestion, It might be in gear. I don't think i shifted it to Neutral while I was trying to get over to the shoulder. I am driving out to AZ tonight, i will look at this, Thanks for the help.

Mike, the 8V engine is not one that can handle over heating. I know you plan to flush the radiator. Pull that radiator and have it rodded out. Also make sure you have fuel to the engine, the same symptoms happen (without the high temp) when there is a fuel starvation. I had algae in my tank that clogged the line to the engine. FYI

Look for antifreeze in the oil first. If you got that you need some engine work done with either a cracked liner or blown head gasket which is not something that comes and goes.

Overheating is something to avoid at all costs with our engines.

Generally this issue can be fixed with a few internal engine parts, avoid getting talked into overhauling the engine; as that is a big ticket item...

Ya can't it will shut down like it did. Or at least it should and it looks like it did.

I just got back from my 300 mile trek each way to work on the Bus, I have good news. UNless I am missing something, the bus didn't shut down due to temperature, it shut down because the 24VDC rear 90 amp Breaker went bad. I moved the red cable from that breaker to the one below it and it fired up from the back start switch. I also read all the fault codes and there were no hi temp faults, but a few High voltage fuel sensors historical faults. I am not out of the water completely yet, I get no crank with the Key still. I checked all the termination points back to the rear start toggle switch, then to the solenoid in the box above the engine. everything checks out, just no crank from the key. freds the engine oil is fine, I let the engine run on High idle for over an hour then checked the dipstick, oil seems fine. All good so far.

Attachment 16711
This is the Breaker. Any idea who makes these? Klixon?

Yes, those are Klixon breakers.

What are folks using for Transmission Fluid these days? While I have the Bus up on Stands, i want to drain the tranny and replace the fluid and filter. I would prefer something Napa carries if possible. The filter is a Napa FIL 1623

Filter: (very Old)
http://forum.prevostownersgroup.com/...id=17007&stc=1
Transmission drain Bolt. I hope I can crack that free.
http://forum.prevostownersgroup.com/...id=17008&stc=1