Just broke down on I-95 S at the Florida/Georgia Border Need Advice

[Scott & Heather]

I'm green behind the ears, and pushed the coach at 70 MPH a little too long this morning. Overheated (200) and shut down. It won't turn over when I press the starter. Is this a safety until the engine cools? Can I just sit and let it cool then try to get started in an hour or so? No coolant leaking, no steam, no drama...just overheated, died, and I coasted into a weigh station. Please tell me that I can let it cool and it will start.    1984 MCI-9 6v92 turbo DD Mech injection. I'm only 100 miles from my destination.

Thanks guys,
Scott

[Ed Hackenbruch]

 Should be able to.  200 degrees  shouldn't shut you down though. Gauge off? someth ing else going on?

[Scott & Heather]

Just as it shut off, the overheat indicator was blinking and the gauge was slightly over 200. My coach runs normally cooler than that.

[TomC]

Does the starter engage but the engine not start?  If nothing is happening-try starting it from the back.  Good Luck, TomC

[buswarrior]

If the dash alarms came on at the same time as it shut down, that is what the auto shut downs of that era typically did.

As for stock dash gauges, they must be considered to be lying until proven otherwise. The numbers printed on the face must be considered worthless. The only thing you might know, is where it points "normally". Without a lot of testing while underway, you cannot trust how much movement means how many degrees of temp rise.

It is not usual for the starter to not engage, as that is the stock bypass for the auto-shut down. You need to have the fuel pressure switch in the circuit in order to keep holding the start button in to keep the engine running. This was discussed in a recent thread on one board or the other.

So, hopefully, it will turn over once it cools, otherwise, start confirming voltage at all the critical points. You might have a coincidence of a starter circuit failure caused by the vibration going down the road, unrelated to the overheat.

happy coaching!
buswarrior

[robertglines1]

Scott keep us posted.  Call if you need to talk thru 812 449 8263  verizon cell   Bob.   Ps  ck all the usual  color of oil   water level   belt tight on fan drive.  look for loose wire on pressure switch (fuel) should be in line with fuel line close to filter. Just a brief once over glance if anything out of place.

[JackConrad]

Scott called me. He said nothing at the starter, not even a click. First we checked transmission in neutral, all engine compartment switches in correct position. Belt on and tight. He then tried starter again and it turned over. He said no obvious water leaks and engine compartment seemed no warmer than normal. Engine compartment gauge was showing around 160 when he was on the phone with me. I told him to check water level before starting the bus. He called back and said he added about 2 1/2 gallons (that filled it right to the fill cap). I explained where the alarmstats were and how to disable them if it did it again AND if the engine compartment gauge shows the proper engine temp.  Jack

[gus]

Too bad, I just passed that same point Tue on my way to LA, I might have been able to help.

As already posted, temp gages are worthless until observed in normal operation. My temp gage reads  around 140* just below the green band when the engine is actually  running around 180* as measured by IR gage. When it reaches the green it is just on the verge of spewing out coolant. When it shows 180* in the middle of the green band it is VERY hot. Had to learn all this the hard way!

My V730 oil temp gage does the same thing, shows around 230-240* when it is actually around 200*.

I've checked all the grounds with a good meter so can only guess it is poor wiring connections, poor wiring or just the long lengths of wire required. One other thought is poor conductivity where the sensors are screwed into the engine - I plan to loosen and re-tighten them to check that out.

[Len Silva]

Your problem might also be unmatched gauge and sender.

[Scott & Heather]

We're finally at our destination  Apopka, FL. Jack, you were so so helpful and you're the reason we're here now. Thank you to all of you for the responses, as well as the phone number (Bob). I did what Jack suggested...topped off rad fluid. Engine was really no hotter to me than normal, but that doesn't mean anything. Basically I have a couple of different scenarios that I will try to sort out over the next week.

1. My dash gauge is lying, and it told the engine to shut down because it hates me.
2. Coach really was overheating and my engine gauge is stuck or lying because it hates me.
3. If overheating, it could be caused by the fact that my exhaust downpipe just separated from the turbo/outlet connection up top next to the turbo. So much of the exhaust heat is blowing into the engine compartment causing things to heat up a bit.

So here's what I did. I let the engine cool a bit with all three doors wide open. After a while it would turn over so I know now that indeed the overheat safety prevents the starter from even turning over the engine until it's cooled down. After putting 2.5 gallons of fluid in the rad, we took off down the hwy and kept it at around 65 mph. Dash gauge flirted with 200 and shut the coach off again...right at an intersection as I was pulling into a T/A for fuel. This time, I was a bit torqued since I was completely blocking traffic. So I opened up my tool bay, got out my sockets and pulled the wires for the dash sending unit and overheat safety kill circuitry. I know that was risky, but step into my shoes stranded 100 miles away from destination and blocking traffic with a homeless guy peering into my engine compartment while holding up a sign to the now blocked traffic indicating he wanted money. He banked today... Coach ran, but floored it went about 5 MPH...for about 500 feet...not sure why it did that. Got it to T/A fueled up, then headed to Apopka. No issues after that...of course the dash gauge was flat. Engine gauge never showed a reading above 180. That being said, at the T/A, I bungeed my engine doors in the open position (pulled out the cotter pin and door open stops so they would open flat against the back of the coach) and drove like that the rest of the way. If it was overheating, there was a ton of wind now blowing around those open doors. Anyway, we're here, hooked up, and I'm about to take a much-needed shower. Thanks so much for the help, and Jack, you made my month. 

Scott

[thomasinnv]

Dash gauge has nothing to do with shut down, that is strictly controlled by the alarm stats at each thermostat housing. Alarm stats triggering a shut down should not prevent the engine from being turned over when you push the start button, it is designed so that you can hold the start button as an emergency over ride to move the coach out of harms way after a shut down. If the alarm stat being triggered did in fact prevent the start circuit from operating, it is wired incorrectly. Being 2.5 gallons low on coolant will cause you to run hotter than usual, these MCI's have very marginal cooling to begin with, and running even a little low will kill you. Also where do you run the oil level? Some people run them a gallon or so on the low side to try and lower oil consumption. If you are running on the low side, that may also contribute to running warmer than usual. Less oil in the crank case means the oil runs hotter and the cooler has to dissipate more heat.

[artvonne]

  The French lost an Airbus over the Atlantic a while back, if you dig into it, the stupid plane is so idiot proof you cant override control inputs that exceed design limits. In a dive where you really need to pull it hard to keep from smacking the surface, perhaps hard enough to exceed design limits that could cause structural damage, the computers prevent excess G loading and null the inputs. They decided it was better to risk total destruction rather than allow pilots the option to be pilots and decide if some structural failure was worth the risk over absolute certain death. So they absolutely died. Smack!

  IMHO, these alarm stats are nothing more than idiot proofing the bus against hurting itself because the majority of drivers Bus companies hire never look at gauges and wouldnt pull over even if they saw the temp pegged or the oil pressure at zero and smoke pouring out the back. It would totally tick me off if my Bus decided I was too stoopid to know whether or not I wanted to risk wrecking the engine over getting the bugger off the road. If I owned anything like that, those things would be discarded ASAP. Im my own Captain, dang it, and I can read a gauge, and can see the back end out the mirror, and I can decide if and when I wanna start my engine, and I aint about to let some bean counter from who knows where decide for me whether it will do harm to MY Bus or not.

[Fred Mc]

So Paul, tell us how you REALLY feel.  LOL

[prevosman]

I admit I resist new stuff. While I still feel comfortable with a set of points and having to set the gap and timing on a car there is no way we can find fault with a system of sensors that shuts our engines down in the event of a problem.

I agree with Paul about planes that limit pilot inputs. That design intended to keep the wings on a plane apparently ignores the fact Mother Nature can put a plane in an attitude that dictates such inputs. But for our buses it is not like we as drivers cannot benefit from the shut down features. I cannot comment on how MCI is set up, but on a Prevost coach, going back to DDECI in 1987 there were only 3 reasons for an engine shut down. They were low coolant level, low oil pressure and high engine temperature. But even those shut downs came with a 15 second warning, and there is a switch the driver can use to over ride the shut down.

Having the coach set up that way, even the least involved driver has fair warning and the tool by which he can get the coach to a safe place. I have seen on this and other forums posts by owners about coaches with high temps, low oil pressure, and indications the owners only deal with issues when they become critical or serious. All the manufacturers are doing is trying to protect the owners from themselves. Seems like a good deal to me.

I don't know what feature shut Scott down initially. I do know on my coach if I had to add 2.5 gallons to my cooling system the low coolant level would have shut me down. It could be the temps that shut him down, or it could be a bad sensor that triggered the event. Regardless of the cause, taking the safety features from the system at some point could cost Scott an engine.

[roadrunnertex]

Look's like every one has given you a lot of very good advise in regards to your overheat problem with your MC-9.
Perhaps I can add a thought so here goes.
I have a very good friend who is a retired intercity bus driver over 38 years of driving buses.
Derf Namyar has driven every thing From the GMC's 4104,4106,4107,PD4501 Scenicruisers and the P8M4905A Buffalos.
MCI,from the 5's through the latest ones MCI has built.
Eagles 01,05,10's
Also the Prevost various models.
He has often told me over the years when it's hot keep your speed down to 60-65 MPH max don't run to fast or it will overheat and shut down.
Nothing worse that coach that has over heated and shutdown with a full load of unhappy passengers.
But he also said a good pretrip inspection is need to make sure all fluid levles are to the full mark.
Also don't forget your tires and tire pressure is part of the walk around check before leaving.
The above are quotes from Derf.
The buses he drove were Oklahoma Transportation Company coaches,Greyhound coaches,And Trailways coaches.
When it was hot in Oklahoma, Texas and Arkansas he would keep the speed down.
He said 99% of the time he would always finish the trip with no problem.
Take it easy nice and slow when it's hot outside.
jlv