We had a somewhat warm day today so I thought I'd run the generator and bus engine to get their fluids moving. First time for the bus engine since parking it about two months ago.
Funny thing happened when trying to start it. Temp was around 45F, so it fired right up. Smoked for a brief minute and smoothed out right away. About 20 seconds later it just cut out. Waited a minute or two, restarted with no problem. This happened a few times till I noticed the low water light was on each time.
I then checked the surge tank and it was low. Added 3-1/2 gallons of coolant mix and she started up again with no problems. Ran the motor on fast idle for about 5 minutes and the buzzer started to indicate low water again. Went out to get more coolant and added another 3-1/2 gallons. Ran it on fast idle until the engine temp hit 180 and the thermostat opened. I search everywhere that I can think of but can find no coolant leaking. The oil level is normal and there is no indication of coolant in the oil.
This coach does NOT have a Webasto or Aqua Hot. Just the OTR heater, which worked just like it should today. No leaks in engine compartment, no leaks around defroster core, no leaks visible around heater core.
Only thing I can think of is that the shop didn't fully fill the coolant when they had it in late fall. The last thing they did was install the block heater. I ran it home from the shop, and then for another very short trip a week or so later. Temps have been cold (very cold) since then.
It's quite a bit of coolant to replace and I am somewhat concerned. You'd think that there would be a puddle under the bus, but since we're parked over fine gravel I'd never see it if it was a slow leak. I'll keep my eyes on the lookout but so far I see nothing dripping since shutting down an hour ago.
Any thoughts where to look for the missing coolant?
Look for yogurt on the dipstick???
Oil looks just fine.
I think I found the leak. The a/c condenser is located in the first bay driver's side. There is an access hatch on the rear side of the a/c bay in the bulkhead that can be accessed from the next bay to the rear.
I opened the access hatch, and all the way on on the front of the bay is the heater circulating pump. It's bolted to the copper coolant lines and had a electric motor. Sure enough, there is a slow drip coming from the circulating pump.
Assuming that I can get a replacement pump, I'll need to practice my contortionist moves to get to the darn thing. Pulling the condenser would allow access, but that would require evacuating (and later refilling) the refrigerant. This coach is still running the original refrigerant, so I don't want to touch this.
If I had a way to get under the bus I'm sure that there is access through the bottom of the bay, since the condenser fan vents down and has a removable screen over it. This might be a job for the shop - not sure yet. Sure wish this was as easy to get to on the 4108 as it is on the 4106 - that one was right out in the open.
Funny thing is reading through the service manual bit about all this. They make it sound like you can just reach in there and pull the pump with no problem. Apparently at one time it was possible to get a rebuild kit for the pump and motor. Not sure what's available now, and won't know till Monday when I can talk to Luke.
Anyone have experience with this? Anyone know if the pumps or parts are still available? Since the whole purpose of this pump is just to move coolant around, I'm assuming that if the OEM pump is not repairable or replaceable it will be possible to retrofit something else to do the job. What fun.
Trying not to stress out over this...
Years ago I added a magnetic drive pump to circulate the coolant through the house radiators on our bus. If you end up replacing the pump take a look at the mag drive pumps because they get completely away from seals which means your leak can't happen.
I would call Luke. If it is still available, either pump or kit, he can most likely get it or has it.
On my list for Monday morning to call Luke. I was hoping someone else has done this and could let me know how it went.
Sir,it may be just the gaskets between the pump and the modulating valve. I remember a few years ago,we installed some special gaskets over there. Thoses gaskets were ticker and stronger than the originals one.
If ever the motor is defect,everyting is rebuild able...
Seems to be dripping directly from the pump, just below the place where the shaft/seals are. Gaskets look like they've seeped in the past, but they are dry now.
The service manual has instructions for rebuilding the pump and motor, but doing that will depend solely on the parts available.
The important lesson for busnuts in this?
Check fluids before start, ESPECIALLY after a period of storage.
Check EVERYTHING after the shop has had it. Hired help doesn't give 2 hoots about your stuff.
Good fortune this time!
Your protection from the bus demons is now expired...!
happy coaching!
buswarrior
Whent the shop refill your engine after the installation of your block heater,they probabely did not start the circulating pump to fill the heater and defroster water circuit. They should have closed the two valves to isolate the bus heating system before draining your engine .They probabely forget to do So.
You say that you put 7 gallons of antifreeze back in the surge tank.....certainly not a dripping circulating pump.
If you have silicone hoses (the blue one) they leak during cold weather I tighten mine all the time when the weather gets cooler
Quote from: Templar52 on January 27, 2018, 08:05:36 AM
Whent the shop refill your engine after the installation of your block heater,they probabely did not start the circulating pump to fill the heater and defroster water circuit. They should have closed the two valves to isolate the bus heating system before draining your engine .They probabely forget to do So.
You say that you put 7 gallons of antifreeze back in the surge tank.....certainly not a dripping circulating pump.
There are anywhere from 75,000 to 90,000 drops of water per gallon, depending on who you ask.
The pump drips about once every 5 seconds when running the pump with the engine at fast idle. That's about 720 drops an hour. Even if the number of drops/gallon for coolant is only 50,000 it would take about 70 hours to drip through one gallon. I've driven the bus about 20 hours total, at most. That would bring me to less than half a gallon lost through dripping. Even if I double the rate of dripping for operation on the highway, it still only accounts for one gallon of coolant loss.
I still want to get it fixed, as I have no idea when it will fail further and empty out the entire cooling system.
That of course brings me to the problem of where all the rest of the coolant went. I opened the access hatch to the heater core and to the defroster core. Both are dry and show no signs of having anything more than some condensation over the years. No dried puddles of coolant, no stains, no corrosion. Even the a/c bay with the dripping pump doesn't really show signs that it's been dripping for that long. All the basement bays are dry. There is no sign of even a drip in the engine bay. Engine oil is fine and at the proper level. No smoke or haze in the exhaust. Can't figure out where the coolant went.
Only thing I can figure at this point is the shop didn't properly fill the thing up when I had them install the block heater. The low-water sensor didn't trigger at the time - maybe the warmer weather at the time kept it from reading low? Maybe there was a large air pocket that finally made it's way to the surge tank? Don't really know.
Anyone have suggestions on where else to look for possible leaks?
I think Richard that there is no leak at all.
The shop did not full the system. They probabely stay with some gallons of antifreeze that was impossible to them to put back in the tank. They do not taught were the rest of the coolant was for. Whent you start your bus last time you brobabely switch on the heater and the circulating pump take some water from the engine to send it to the defroster or heating radiator who were empty at the time. 7 gallons is approximately what the heating system use.
So don't worry...be happy that this problem appear on your driveway and not on the freeway.
I agree wit Templar52
That may be the very reason why your coolant circulating pump is leaking now - for it may have ran "dry" for a spell and coprimised the seal...
His bus should take 19 gals for the entire system ? how much coolant will the heater and lines take to fill,the engine alone holds 8 gals,then radiators on buses take the same amount or more that only leaves 3 gals if my math is correct 7 gals of coolant is a lot that is over a 1/3 of the total capacity of the system,he has a leak some where
Regardless of how it came to be, the circulating pump is leaking now. I need to either change the seal or the entire pump. I'm guessing that there has been at least a minimal leak at the pump for a short time due to the corrosion on the end of the motor casing.
Anyone ever rebuilt one of these pumps? How about replacing one?
Aside from getting the parts, I'm puzzled how I'm supposed to reach the darned thing. It's one other side of the bay from the access hatch, and even being as small as I am it will be nearly impossible to reach in far enough to use two hands to work on it. Love to hear if someone else did this, and if so was there any access from the bottom by removing the a/c condenser fan.
You may want or need to create your own access (cut an opening) to get to that rascal...
Luvrbus,
The cooling capacity for 4106 bus is 24 gallons including the heating system,according to the manual. Should be the same for a period Buffalo.
I just did a anti freeze changed on a 4905 and it was 5 ft longer 21 gals with the front heater since the coach heat was removed did one on 4106 without the factory coach heat it only held 18 gals so I don't know what up on the GMs
Here's a couple of pictures of the problems.
Apparently the water modulating valve has been leaking in the past, but it was dry when I tested it this week. I'll have to check again next time I can get it up on the highway for a while.
The circulation pump looks like it has been leaking longer than just a few days. Don't think this leak happened from running it for a few minutes low on coolant the other day. I wouldn't be surprised if this has been leaking for a few years.
The system's total capacity is 92 quarts (23 gallons) per the manual.
I was able to get in the bay through the access hatch, which is about 16" x 16". At least I got my head, shoulders and arms through. What makes it really tough is that the area in front of the access hatch only has about 12" clear before the basement a/c unit. I had to have someone standing by to help get me out. Once inside the bay, I was worried about touching the back of the condenser coil and damaging the fins.
Not sure if I'll be able to do any repairs through the hatch though. Looks like it would be easier to get in from underneath by removing the condenser fan assembly. My goal today was just to verify that if absolutely necessary, I could get my hands on the pump.
I had thought about cutting another way in, but there really isn't one. On the other side of the bulkhead where the pump is mounted is the fuel tank. Across the bulkhead towards the passenger side is the heater core and ventilation unit.
Next step will be to have a chit chat with Luke and see what options exist. That will determine what comes next. As always I welcome any suggestions. (https://uploads.tapatalk-cdn.com/20180127/0af2b8c17e9b33c609ce46b0d49f12c9.jpg)(https://uploads.tapatalk-cdn.com/20180127/a7b410df3a4ae30492c918615e3ae6e4.jpg)
Those look more like oxidation and electrolysis to me.
Leaks are wet.
Quote from: eagle19952 on January 27, 2018, 06:37:03 PM
Those look more like oxidation and electrolysis to me.
Leaks are wet.
You might be correct about the water modulating valve.
The pump was definitely dripping coolant when I ran it yesterday.
I just was out at the bus and topped off the coolant. Needed another gallon to bring things to the bottom of the filler neck in the surge tank. That makes 8 gallons total, or about 1/3 of the total capacity of the system.
This last fill came after running it for about 45 minutes yesterday to bring the temp to 180 degrees to open the thermostat. I still don't see a drop of coolant anywhere in the engine bay or around the radiator. Not a bit of moisture that I can see around the defroster or the heater core. I checked the oil after full cool down to ambient temp and it is still spot on at the 'full' mark and still looks like just oil (no sign of water or any other contaminant).
This is a lot of coolant to replace. If they didn't fill it properly at the shop could they have missed it by this much? Seems unlikely that the dripping on the circulation booster pump could have caused this much loss on the 40 mile trip home from the shop or the 30 mile drive we took it on the week after. Hasn't moved since then. The OTR heat ran good on warm on both of these trips, so if there was an air pocket it wasn't causing a total airlock to the front of the bus.
The bus is parked on a grade with the nose higher than the tail. If anything that would seem to raise the level at the surge tank, not lower it.
I'm at a loss where the coolant went. Suggestions?
I don't think they got it full. The switch in the coolant door is there to run the pump to force coolant through heating system to purge trapped air. I don't think coolant can get past pump if it is not on, to purge air in system. That's why the pump switch has to be held in the on position for this purge. Once done, pump runs as needed with normal operation. If you decide to pull pump, after removing clamps, slit the hose lengthwise with a sharp utility knife. Much easier to remove than doing a lot of prying with a screwdriver.
Quote from: chessie4905 on January 28, 2018, 01:13:53 PM
... If you decide to pull pump, after removing clamps, slit the hose lengthwise with a sharp utility knife. Much easier to remove than doing a lot of prying with a screwdriver.
I wish it were as simple as slitting the hose to remove this thing. Take a look at the photo I posted below and you'll see that this is a flange-mounted pump. The flanges mount directly to matching flanges on the ends of the copper piping. I'm anticipating that this is going to be a royal bugger to get out of there. Hopefully the bolts turn and the gaskets let loose. Otherwise I'm on to plan B.
Of course, I'll have to find out what parts are available first...
I have some duos on stock but they are all 12 volts . Is your bus is 24 volts ?
Yup - 24v
I was talking about the hose connection only. I realize there are also bolts to remove.
Quote from: chessie4905 on January 28, 2018, 02:32:54 PM
I was talking about the hose connection only. I realize there are also bolts to remove.
Maybe I'm confused here. It looks to me like the only thing that connects this pump to the coolant lines are the two flanges. Did I miss something in there?
All I saw in there are two copper lines covered in soft rubber insulation that connect to the pump at the flanges, and the two wires going to the motor.
Our 4106 had rubber hoses, but the one on this 4108 seems to be connected more directly.
I'm not doing well this weekend being patient waiting to talk to Luke - kind of stressed over whether there are parts available. I don't know why this is bothering me so much since I imagine there is a work-around if the pump is not on the shelf. If I know something is repairable I can deal with it, even if it's a big job. It's the not knowing that gets me every time.
From the looks of the manual, the 4108 and the 4905 share the same circulating pump setup.
Probably same as all 4905s. Shouldn't be a problem getting kit or replacement unit.
I have a later model MP brass pump with the new style motor I removed my my MCI if you have trouble finding parts for your older pump this one should work and I will send it to you if you need it
Yes, it's connected with flanges, however after removal, I would replace that piece of boss while you are there. From the pictures you can remove pump by removing bolts at one flange and disconnect other side by removing hose that connects line to other flange. Once out, you can remove other flange, New gasket, never seize on cleaned or replaced bolts.
Quote from: chessie4905 on January 29, 2018, 10:03:47 AM
Yes, it's connected with flanges, however after removal, I would replace that piece of boss while you are there. From the pictures you can remove pump by removing bolts at one flange and disconnect other side by removing hose that connects line to other flange. Once out, you can remove other flange, New gasket, never seize on cleaned or replaced bolts.
Both flanges of the pump are mounted directly to flanges which are connected soldered to the copper pipe. There is no hose. The top picture is the one with the pump, and what may look like hose is the rubber insulation over the copper pipe.
The bottom photo of the water valve (says Honeywell on it) is the one with one flange and hose on the other side.
Quote from: luvrbus on January 29, 2018, 08:51:21 AM
I have a later model MP brass pump with the new style motor I removed my my MCI if you have trouble finding parts for your older pump this one should work and I will send it to you if you need it
Is the pump you have also mounted with two flanges or does it use rubber hose?
Quote from: richard5933 on January 29, 2018, 11:13:58 AM
Is the pump you have also mounted with two flanges or does it use rubber hose?
2 flanges connecting to 1-1/2 O.D. copper pipe.I think it is a booster pump not a circulating pump probably could be used for circulating pump unless it moves the coolant to fast I don't know what the GPM specs are
Quote from: luvrbus on January 29, 2018, 11:59:14 AM
2 flanges connecting to 1-1/2 O.D. copper pipe.I think it is a booster pump not a circulating pump probably could be used for circulating pump unless it moves the coolant to fast I don't know what the GPM specs are
What I've got is technically called a booster pump as well. Any chance you could shoot me a photo of what you've got? My email is posted on my profile if you need. Seems like what you have might be what I need.
Quote from: richard5933 on January 29, 2018, 12:02:19 PM
What I've got is technically called a booster pump as well. Any chance you could shoot me a photo of what you've got? My email is posted on my profile if you need. Seems like what you have might be what I need.
Your Email is hidden and I cannot find a place for a attachment in board software
Booster pump or circulating pump is the same. The Honeywell valve is a MODULATING VALVE. This valve open whent you need hot water in your heater radiator or defroster. The valve is connected to your thermostat. The pump help sending the hot antifreeze to the defroster and thrue the heater radiator.
You better change both of them. While you are in the same corner.
Quote from: luvrbus on January 29, 2018, 12:35:04 PM
Your Email is hidden and I cannot find a place for a attachment in board software
The water circulating valve is connected to a gradustat which controls water temperature. The valve is controlled by air pressure, which is manipulated by gradustat.
My shop manual mentions to remove flanges or hose to remove pump. Maybe early models had hoses. I didn't see any seal kit for pump, other than replacement impeller. They suggest that if seal is or shows signs of leaking, to replace assembly. To me, that means pump assembly. The pump appears to be bronze, so good chance those bolts will remove without drama. Be sure to spray penetrant on bolts for a couple of days before to give it time to soak in and free up. Check condition of brushes while you have assembly out. They do list packing for water circulation valve btw.
Quote from: luvrbus on January 29, 2018, 12:35:04 PM
Your Email is hidden and I cannot find a place for a attachment in board software
Clifford,
I did get the photos you sent and think what you've got will work.
I tried to reply via email and PM, but I'm having trouble on this end getting the electrons to cooperate. Just checking in to see if you got my replies.
Get me a shipping address you can have for the shipping it doesn't show any signs of leaking or corrosion,but you will need to repair 1 wire I broke off by accident when I picked it up
Quote from: luvrbus on January 31, 2018, 09:04:41 AM
Get me a shipping address you can have for the shipping it doesn't show any signs of leaking or corrosion,but you will need to repair 1 wire I broke off by accident when I picked it up
Sent via PM. Please let me know if you got the information.
Thanks again for your help with this!
I got the address boy that is a lot of numbers for a address will ship it out Friday when I go to town and it is 24v
Quote from: luvrbus on February 01, 2018, 05:49:18 AM
I got the address boy that is a lot of numbers for a address will ship it out Friday when I go to town and it is 24v
I'm told that there are something like 7 counties in the US that still use an older coordinate address system like we do. The letters & numbers in our 'house number' are grid coordinates, and the zero point in the system for us is a point near downtown Milwaukee.
Back in the days when our area was rural farm country and the roads had no names (or there were no roads, just dirt trails) the fire squad could find a location just by using a grid map. Theoretically if you had just the coordinates you would be able to locate our house even if you didn't know what the street name was, was town we were located in, or anything else.
The system worked really well for many years, but it has probably outlived its usefulness. Sure is fun when we try to mail order something and they only have four or five digits in their system for a house number.