| Author |
Message |
Mark Price (Hoosier_highway)
Registered Member
Username: Hoosier_highway
Post Number: 1
Registered: 2-2007
Posted From: 67.173.99.85
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 14, 2007 - 5:26 pm: | |
We have a 1983 Prevost with a DD 8v-71. At highway speeds with the shutters open manually the temp hovers around 160-165. If I activate the shutters (closed below 180) they never get a chance to open becuase at around 170 the high temp shutdown happens. These temp readings are from the dash gauge. Yesterday I replaced the rear machanical gauge but could not get the temp up to over 120 standing still. It has been snowing for 2 days so I can't take it out to get the temp up to compare the rear gauge with the dash gauge. I need to know where and what is causing the high temp shut down. It is my understanding that the high temp shut down is around 205 - 210. I don't think I'm getting even close to that because I have very little heat out of the bus heat or defrosters. The defrosters are warm when on low. The bus heat is just cold. We have been leaving the shutters open and we do just fine. However it is February and very cold out. I can see this becoming a big problem when it warms up. Thanks, Mark |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 192
Registered: 7-2006
Posted From: 66.217.105.58
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 14, 2007 - 9:45 pm: | |
"... the high temp shut down is around 205 - 210. I don't
think I'm getting even close to that because I have very
little heat out of the bus heat or defrosters. The defrosters
are warm when on low. The bus heat is just cold. "
Ok... dumb question of the month (or in my case, minute):
Are you sure the system is full of coolant? If not, the engine
can overheat without anything else getting hot.... There's
40+ feet of hose from rear to front, times two (gotta' return),
that's a lot of coolant.. If the dash gauge's sensor isn't in
the coolant, it'll read a lot lower than the engine temperature..
Having one of those $40 Non-contact Laser Thermometers
from HF might be a worthwhile investment!
Or that $9.99 one?
(go ahead, shoot me) |
Mark Price (Hoosier_highway)
Registered Member
Username: Hoosier_highway
Post Number: 2
Registered: 2-2007
Posted From: 67.173.99.85
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 14, 2007 - 10:17 pm: | |
While changing the rear temp gauge the coolant poured out like Niagra Falls and the upper tank has coolant in it. I have a laser temp gauge but I don't carry it with. I will pack it for the trip to Indy this week end. The low coolant light has not come on, Not sure if it works though. Thanks, Mark |
james dean boggs (Jd_boggs)
Registered Member
Username: Jd_boggs
Post Number: 107
Registered: 11-2004
Posted From: 75.80.240.25
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 12:07 am: | |
It may be shutting down for a different reason. My electrical diagram on a 6v92 shows a circuit which causes engine shut down if fuel and or oil pressure (sp) is low. Do you have this problem when the temp outside is 80 degrees? |
Mark Price (Hoosier_highway)
Registered Member
Username: Hoosier_highway
Post Number: 3
Registered: 2-2007
Posted From: 67.173.99.85
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 10:49 am: | |
We purchased it in October. So No 80's yet. I can pin point the first time it happened. We were trying to get more heat out of it so I closed th shutters on our way up into Michigan. About 30 min. into the trip it shut down. After the third time I opened the shutters and it never happened again. |
Richard Bowyer (Drivingmisslazy)
Registered Member
Username: Drivingmisslazy
Post Number: 1831
Registered: 1-2001
Posted From: 75.108.87.29
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 11:02 am: | |
After losing antifreeze remember to bleed the air out of the heater system. You will never get any heat up front if there is air in the system.
Richard |
Mark R. Obtinario (Cowlitzcoach)
Registered Member
Username: Cowlitzcoach
Post Number: 133
Registered: 4-2001
Posted From: 204.245.250.168
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 11:20 am: | |
I see that you have two issues and both are related to temperature.
I think the first thing you need to determine is if your coolant system is full of coolant.
I have a Crown with a 6-71T. I have a leak in the water manifold I haven't been able to stop completely. At times the coolant level will go down far enough that the temp gauge will spike even though the coolant lines to the heater are stone cold. Upon refilling the radiator the temperature on the gauge goes back down to the bottom and no more high temp buzzers or shut down.
The second issue is whether or not your engine really is getting too hot. An infrared thermometer is really handy to figure out which gauge is telling the truth and which one is lying.
Your problem may be as simple as a high heat shutdown solenoid that is faulty. But you won't be able to determine that until you know for sure what the temperature is your system.
Good luck and keep us posted.
Mark O.
Castle Rock, WA |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 196
Registered: 7-2006
Posted From: 66.217.107.144
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 11:23 am: | |
"About 30 min. into the trip it shut down. After the third
time I opened the shutters and it never happened again."
Patient: My arm hurts when I go like this....
Doctor: Don't go like that.
Don't close the shutters.
(or find out why they're not opening as the heat increases....)
You might want to check for air in the coolant lines that run
to the front. If you don't bleed the air out, the coolant won't
flow properly to the cores, and you won't get enough heat
out of the defroster to be worth squat. There's a bunch of
valves on the MCIs that have to be opened manually, but
I have no clue what's on those Prayvosts.. One valve that's
not opened fully, and you're going to need hotter water to
feel even a lil' heat.
The guy I bought my MC9 from had the shutters locked into
the open position to avoid an overheating problem. But with
the lines well bled, and all valves wide open, there was plenty
of heat to the defrosters... even while the engine was warming
up... Uhh... did anyone check the thermostats?
You'd do well to use that Non-contact Laser Thermometer
you have... As least you could isolate the problem first-hand.
All you're going to get here, are guesses.. Some good, and
some like mine. |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 197
Registered: 7-2006
Posted From: 66.217.107.144
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 11:28 am: | |
Holy ^%#. I took so long to type and post that last one, everything's
already been said..
AH-HAH.... The votes are in! Dump the Prayvo and buy a BlueBird. |
larry currier (Larryc)
Registered Member
Username: Larryc
Post Number: 35
Registered: 2-2007
Posted From: 207.200.116.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 15, 2007 - 1:02 pm: | |
Mark, If you missed a valve to the heat, its gonna be cold. If you have a bad shutterstat they will never open, the engine will get hot and the electronics will shut it down. Until proven other wise, work on that senario first. Follow the air lines to the little copper guy on the block. It can be checked in hot water like a thermostat. Put an air line on it and blow into it to see if it passes air at the temp stamped on it. |
Mark Price (Hoosier_highway)
Registered Member
Username: Hoosier_highway
Post Number: 4
Registered: 2-2007
Posted From: 67.173.99.85
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 19, 2007 - 5:24 pm: | |
O.K. Had a show in Indy this week end. Stopped on the way to check engine temp on NEW rear gauge and with a "laser" temp gauge. Rear gauge read 165 degrees, dash gauge read the same. With the "laser" gauge I could not find a temp over 100 degrees anywhere. I checked the entire engine, radiator even the exhaust manifolds. The radiator core was only 80 degrees. Not sure how usefull this is, it only reads surface temp? I am going to change the temp sending unit this week. And then check the shutterstat.
I closed off all of the outside air vents and that improved the bus heat and defrost temps. We were drawing a ton of outside air into the a/c condencer bay from each side of the coach. This really helped raise the air temp coming out of the coach and defroster vents! We actually had to turn down the defroster thermastat. |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 209
Registered: 7-2006
Posted From: 66.217.108.59
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 19, 2007 - 6:49 pm: | |
"I closed off all of the outside air vents and that improved
the bus heat and defrost temps. "
Wow. How many of us totally forgot about those controls? |