| Author | Message | ||
| Moti Nowrangi (Mnowrangi)
Registered Member Username: Mnowrangi Post Number: 6 Registered: 2-2009 Posted From: 96.255.83.117 Rating: |
I noticed that while on a trip with my MC8 the engine shut off automatically - there is a sticker on the dash that says "not equipped with emergency shut-off". What is the difference between AUTO shutoff and EMERGENCY shutoff? And what could trigger either of the two? Thanks! | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 997 Registered: 12-2000 Posted From: 71.3.75.244  Rating: N/A |
Auto shut-off will turn the engine off if the oil pressure is too low or the engine water temp is too high. Emergency shut-down is a switch near the driver that , when activated, closed a trap door in the air intake, shutting off the air supply to the engine. This switch was designed to be used in the event the engine "ran away" with RPM continuing to increase until the engine self destructed. What engine do you have in your coach? 8V71, 6V92 or 8V92 (8V71 will not be turbo charged, 6V92 & 8V92 will be turbocharged) Jack | ||
| Moti Nowrangi (Mnowrangi)
Registered Member Username: Mnowrangi Post Number: 11 Registered: 2-2009 Posted From: 96.255.83.117 Rating: N/A |
Auto shut-off will turn the engine off if the oil pressure is too low or the engine water temp is too high. Emergency shut-down is a switch near the driver that , when activated, closed a trap door in the air intake, shutting off the air supply to the engine. This switch was designed to be used in the event the engine "ran away" with RPM continuing to increase until the engine self destructed. What engine do you have in your coach? 8V71, 6V92 or 8V92 (8V71 will not be turbo charged, 6V92 & 8V92 will be turbocharged) Jack I have a V8 - 71 series detroit engine 2 strock. My water guage after the bus has warmed up shows 250ish. I had the bus heater running with the water valve open two days ago without incident expect for on the way back i noticed it wasn't warming up enough. Then yesterday I closed the water valve and turned on the A/C - could that have triggered something along with a drop in oil level/preasure to cause heating which inturn caused the bus to shut off? I did add an extra two more gallons of oil and let the bus rest for about 3hours after which it seemed to operate well on the way back home. Would the addition of excess oil cause a future unseen problem? Or would the excess just leak off. I know these engines did have a leaking inherrent problem built into them... | ||
| David Dulmage (Daved)
Registered Member Username: Daved Post Number: 236 Registered: 12-2003 Posted From: 142.46.199.30  Rating: N/A |
Engine temperature should be closer to the 180 F mark. It seems like you may be running with low coolant or with one or more thermostats stuck. That fact that you weren't obtaining sufficient heat suggest to me that the coolant is low. Dave Dulmage | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 843 Registered: 7-2006 Posted From: 74.162.92.56  Rating: N/A |
Moti - Regarding your two posted threads asking the same question: "-300 mile trip - it performed beautifully. I had the heat running and the thermostat set at a number 3 position - on the return trip, I noticed that the bus wasn't getting warm as it should -So, trying to trouble shoot with a load of passengers, all I could think of was adding a gallon of oil - the bus started ...but then again cut off 10 min up the road. -I had the bus heater running with the water valve open two days ago without incident expect for on the way back i noticed it wasn't warming up enough. Then yesterday I closed the water valve and turned on the A/C - could that have triggered something " Although running the bus while low in coolant may (or may not) cause it to overheat; having a faulty functioning radiator, or circulation within the engine components, -will- cause it to overheat. If the system is either stopped up, or the radiator dampers are closed, it will run cooler with a the passenger heat on, than it will off. The engine water will travel the full distance from front to rear of the bus, when the heat's turned on. When you turn off the valve, the water is held to the engine's system, and if it's malfunctioning, the engine will run hot.... and if everything in the "protection" circuit is operating properly, the engine will shut down. (The dash gauge may continue to read low, even though the engine itself is overheating, btw) You shouldn't "add oil" if the oil is at the proper level, or only a "quart low". An overheated engine will also produce a lower oil pressure reading, since the oil will be thinner; Check the dipstick. If you're using that bus to carry passengers, you really oughta' have a bus garage inspect it, and give you some input as far as it's road worthiness. You'll never carry a more precious commodity, than human beings. Bus drivers never worried about fixing the bus. If we sensed a problem, we took it in to the closest bus garage and had it fixed. Our responsibility was to our passengers. As an owner/operator of a bus doing commercial duty, your obligations are the same. Having the engine quit while full of passengers, can be disastrous under some conditions. If the engine stops, your air system will soon follow (since it's powered by the engine). Shifting into neutral while rolling, when the engine dies.... leaves you without any provision to stop, or slow the vehicle down if/when you lose the air brakes. Even stalling at an intersection or on/off ramp leaves your passengers vulnerable, just as it does to have them sitting aside a highway. In my opinion, you should have the cooling system checked. It sounds like it's the contributing factor of your engine problem. And locate that oil dipstick, and mark it, so you remember what it's for... Lotsa' luck. | ||
| Moti Nowrangi (Mnowrangi)
Registered Member Username: Mnowrangi Post Number: 12 Registered: 2-2009 Posted From: 96.255.83.117 Rating: N/A |
Thanks all for your input! This is a BBB and your suggestions and recommendations are valuable. It is a fabulous bus and I love it and although been given a road worthiness bill of approval from atleast 2 authorized garages, it is a used piece of equipment and like anything subject to mechanical failure when you least expect it. I think a combination of low oil and low coolant levels triggered this incident. Needless for a 1974 model year with only 300,000 miles on she still has a lot of living to do! Ofcourse one can read all bout it in a book or take it to a garage and pay for a diagnostic, but the first hand info that comes out of this BBS from the experiences and knowledge from the many of you is a valuable tool for anyone including myself! It never hurts to ask! Cheers! | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 51 Registered: 11-2007 Posted From: 195.23.214.142 Rating: N/A |
My MC8 also shuts down if the coolant level in the header tank is too low. The header tank has a sight glass with a level switch at the same height that is used by the test level switch on the rear control panel - and a couple of inches below that one is the coolant level shut-down probe. If your engine starts and shuts down 30 seconds later, this could be the problem |
