Water temperature

[pennuja]

I took the bus out for a drive this morning and the water temperature does not go above 150, however the other day it did. I checked the coolant and it was very low I think I added 5 gallons to get it full.

What would make the temp stay so low does it sound like something is plugged up maybe a bad water pump? I would think if the thermostat was not working the temp gauge would read too high.

I do not see any water in the oil or leaking any where.

[B_K]

Not having enough coolant in the system to reach the sending unit will cause bad/false readings.

Let's hope you don't have internal damage 5 gallons is a lot to add!

Always ck water & oil before starting!
  BK 

[pennuja]

That is what I am afraid of I noticed that I was losing power after a small hill, it was dark and I was unable to see the temp gauge (no light on it) i had been checking it with the drivers light and it was a little over 150. I stopped and added water but it was probably too late.

I know that the sensor was good the other day because I never too my eyes off of the temp and it went a little under and a little over 180 always fluctuating. Today it was cold and I figured that was why it was lower.

[chessie4905]

   The thing is... where did the water go. Been worked on, sitting a long time with slow leak, or in pan? What coach and engine? List coach in your info will help now and in future. Is you oil level normal? Did you just get this coach? How long has it set? How far did you drive it? If you did actually overheat it, damage could be from mild and you got lucky to costly with cracked head/s and more.

[pennuja]

Sorry it is a PD-4104 6-71.

It did sit for 5 years it did not lose any water before I purchased it when it was driven normally. I have not seen any water leak out anyplace and the temps have been good, I only have driven it for a couple of hours total though.

The oil level is good and oil pressure is good too.

The hose on top of the engine connecting to the thermostat has hot water in it, there is a valve there and I opened it a tiny bit. I think that this goes to the radiator but I am stating this from memory.

I dropped it off at a diesel mechanic that is close by to have it checked, I did not want to continue driving it.

[luvrbus]

If that was a seated 4104 and hasn't been changed won't it have the reverse flow bypass stat that stays open when under 170 degrees ? It probably bypassed and sent the water to the heating system

[chessie4905]

   The valves are back against the firewall by the radiator to connect to the heating system for interior. That would definitely  cause the water to drop by that much if the heating system was empty. Question is...why would it be empty? Is the heater core leaking? Need to check for that now also. We always shut those off in summer weather, as it also goes to the defroster/dash heater core and added heat to the interior when you didn't need it, even when the blowers were off.

[pennuja]

The heating system seems to be working, it was damp this morning and I had the defroster on all I did was flip the switch to low but it was warm.

I was going to remove the thermostat and see if it was bad but I do not think it is that easy to remove unless I am doing something wrong. It appears that there are a few (maybe 4) nuts on the face of the housing that are easy to remove. Then in the back there are 2 that connect to a lower pipe and these seem very difficult to remove. Is the thermostat as difficult as it seems to remove?

Jim

[chessie4905]

   What was the outside temp when you drove it? Does it still have shutters? Do they work? If the shutters stay open all the time, it'll run that cold except till you climb a grade or work it, or put 10 or more miles on it if temps are on the cool side. It is possible the thermostat is stuck open or missing. It is somewhat a pita to pull that cover off since the big hose is connected to it. Be careful on the bolts, loosen evenly, don't snap any off and then tighten evenly so you don't break an ear off the end. There is a valve in the shutter cylinder air line to shut off the air supply so they they stay open; some owners do this in hot weather. The coach has a shutterstat that controls the opening and closing of the shutters. It is basically a thermostat that controls air flow to the shutters. There is also a reservoir that is supposed to contain fluid to lubricate the shutter cylinder mounted on the shutters. That is where the shutoff is. Too much info overload Huh?

[Seangie]

Have you shot the thermostat blocks with a temp gun to check that the temp gauge is accurate?
A loose wire or rust/build up could cause the gauge to be incorrect. 

-Sean

Wandering the country in a 1984 Eagle 10S. 
www.herdofturtles.org

[pennuja]

Thanks again guys, it was in the 50's I believe and I do not see any shutters, plus to make matters worse there are 2 electric fans mounted on the outside of the radiator, one of them was definitely spinning not sure about the other and I do not think there is a switch to stop them so this may have made it cooler also.

I think I have governor issues too since my idle is going up and down but I do not think that is what was causing the loss of power. When I added antifreeze I let the engine cool down before restarting it then I drove a couple of miles and I could not keep up the RPMs. I was not blowing smoke at any time either. Before I keep running it is there a good way to check if the possible overheating caused any damage. Like a compression test or inspection plate if I did any damage I would hate to worsen it although I think it is already too late.

I should probably add that my engine has jake brakes installed and the switch on the governor for them is damaged, I would think that this could also cause a loss of power but I do not know enough about how they work.

How many hours would a mechanic charge to remove the thermostat, since it is parked at a shop now I could have him remove it and see if it is bad or just have it towed home. I do not think it is something that I want to fix on the side of the road.

[luvrbus]

I think you are worrying to much the 6L71 will tell you when it is tired if you are not blowing smoke,water and oil I wouldn't worry about it, just find out where the water went me I think the reverse flow thermostat dumped it the heating system the way GM design it to do.

Buy a IR temperature gun and shoot the in and out side of the thermostat housing no need to remove it.

The electric fans are not good a good sign it has a cooling problem or those would not be needed

The hunting of the governor is normal for a old single weight governor the power loss could be fuel filters or the strainer if the bus still has it,sit back take a break and relax buy the books read and get up to speed you take it to shop with out any knowledge of what is going the shops just see $$$$ signs JMO

[DMoedave]

good advice. if you don't have water in your oil relax. hit the archives, do some reading as suggested. you have to keep your rpm's up no lugging. The infared guns are under $50 bucks now at sears. a must have. You can check wheel bearings, brakes, and your coolant/engine temps at various spots. Its great that your temp guage works no just verify its accuracy. Many times we have had to sit almost at the top of a long grade in the summer, parked at high idle, to bring our temps down then finish the climb. If your worried about $mechanical expenses you are going to have to start with a good pair of coveralls and climb on in. Your peace of mind will grow as you get the little maintenance things under control.

[eagle19952]

unfortunately unless the shop is old school Detroit savvy...you'll be paying dear $$'s for them to learn....spend the cash on books, DD 6L71 Service Manuals and you'll be $$$$'s ahead. The money they will charge buys A LOT of tools.

We are talking about an engine technology that was state of the art in the 1930's back when steam engines were seeing their last days of glory.

If you are confident working on a model t or a 57 Chevy you'll be better off.

To bad the guy that wrote Volkswagen for dummies didn't write for DD. Seriously the old school Detroit single weights are pretty darn simple....now (if needed) go rent a pallet jack, get a 100$ welder and pull your own motor....IF YOU NEED TOO.

PS all the books you need are free on line .pdf's for the 4104. Do you have them ?

[robertglines1]

Hey-don't knock steam engines just kidding it's just a hobby with my son Andy. Truth is the guys a re correct. Look for the oldest guy in shop or someone that has worked on oil patch engines. Like steam those engines are simple compared to newer ones. Bob PS the onlooker in orange has a MCI 7 tandem.