MCI 102A3 - coolant pump information needed (and how to add coolant?)

[daveola]

I have a 102A3.

My coolant recovery pump has stopped working, and adding coolant to the surge tank is near impossible since the cap for it is not only up high, but higher than the access door.

Anyways, it's time to replace it.

The one in my bus is a ShurFlo 2088-574-534.

My bus seems to hate ShurFlo and FloJet pumps, I use to use them for water and they'd die every year.

Evidently it's a 3.6GPM pump with a 45psi demand switch (though I'm not sure why it'd need that since it is automatically operated by the bus).

Instead of buying a (not so) ShurFlo pump and spending hundreds of dollars, I'm noticing that there's plenty of solar water pumps that are 24V and can handle hot water for *much* cheaper on ebay.

Has anyone tried a different pump for the coolant recovery tank?  And is a ShurFlo even what the bus started with?  Any ideas on what stats I need to concern myself with?

There's a part of me that thinks that even a much slower pump would work because returning coolant from the recovery tank to the surge tank is uncommon and doesn't need to happen in a rush.

[daveola]

I just noticed in the parts manual that the pump listed there is 40 psi, but it doesn't give any other info on the pump.

Anyone know what the requirement are for this pump?

And also, what is the route for coolant going up to the surge tank, on my bus it doesn't seem to go up to the surge tank, is it just pumping coolant directly into the coolant lines down by the engine in order to fill up the top tank?

[Scott & Heather]

Someone elaborate on this? I've never heard of a coolant pump for the surge tank. I just thought heat and pressure expanded the coolant and pushed it into the surge tank thermally and when things cooled down it sucked it back into the cooling system??? Is this some sort of other coolant circulation system for something else?


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[Paso One]

I thought all buses  had the small coolant pump installed.

The purpose of the pump was to take the water from the back of the bus to the drivers heater at the front 35 to 40 ft away.

I have repurposed those pumps ie: to replace the Webasto circulator pump that is way over priced.

I currently have two original pumps installed and working fine for that purpose, it keeps the expansion take tank full.

[blue_goose]

My 102C3 has a recovery tank that is below the AC compressor.  Coolant is pumped from there into the tank that is above the cooling system.  I had to replace the pump and used a Sureflow.
Jack

[buswarrior]

On a related note, a friend's new to them 102C3 has the pump, it runs, but it won't move any coolant.

Lines maybe plugged?

MCI put this system in in order to add coolant. The surge tank is up behind the rear roof cap in the C and D, the "filler cap" is impractical without using a supply hose under pressure, and an awkward stance at the top of a ladder.  The flat rectangular tank is mounted under the AC compressor, with the familiar "filler cap" on it, the electric pump is mounted just above, behind the tail lights, and is supposed to send the coolant you put in the lower tank, up to the surge tank. The toggle switch is mounted on the rear engine control box. There is a sight glass way up there on the surge tank to know you are done.

Nice system, (when it works) everything happens at ground level, much safer...

happy coaching!
buswarrior

[daveola]

Exactly as buswarrior describes, except I haven't seen a sight glass on my surge tank (nor do I know how I can view the top of the surge tank while down by the switches), the only way I know to fill it is to run the pump until it starts to leak.

Evidently the bus is also supposed to automatically run the pump when the surge tank gets low, don't know if that's happening on mine since so many of the indicator lights aren't working.

[jackhanow]

My 102a2 just has a sight glass. I found after I fixed all the small leaks and a new waterpump. I don't have to get my folding platform out to re fill it anymore. I would think that if it goes down so far but no further after filling that maybe your just overfilling the system thus it always overflowing. My sight glass is right in the center of my expansion tank. Usually my wife looks while I fill.

[Scott & Heather]

Interesting. Neither my 9 nor my 102C3 have this pump setup. Just a normal surge tank sitting above the squirrel cage radiator blowers.


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[jav9956]

Perhaps you can make out the image below, I believe this will help. It is the water pump for the coolant recovery system. I too had issues with this but did not have the time to really check everything out... I had to get coolant in the system and get back on the road. I used a siphon hand pump to get the coolant in the surge tank. It was a PAIN and a messy job. The coolant recovery tank was definitely full, coolant would come out when I lifted the fill cap. I think the pump is likely not working on my bus as well and would like to get in there and fix it. You are supposed to fill the coolant through the recovery tank but it doesn't help if that is disconnected from your coolant system via faulty pump! Any insight on how to diagnose and specs to replace would be great. I will probably take a closer look at that this weekend and see if I can maybe pull the part. Anyhow, hope this helps someone.

[jackhanow]

My operators manual says the fill tank is inside the right hand engine compartment door. Says turn the battery switch on and the light should come on. If not test light. Fill tank then hold pump switch on open vent on cross over tube. Refill tank when pump stops until system is full. Close vent when coolant pours out. Light Turns off when system is full. Light and switch are on the remote box. To test the pump. Use a test light and see if it gets power when you turn the switch on.

[Scott & Heather]

I'm so intrigued. Never knew some buses came with this. As I mentioned, I don't have this on either of my buses. I just have a fill door and cap up high on the curb side above engine. Goes to the surge tank and that's it.


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[jav9956]

Scott -

I kind of wish all I had was a fill cap! Though the recovery tank is meant to be helpful it is one extra thing that can break... and when it does it is a mighty big hinderance!

[AdamWalkup]

This pump came out with the "flat back" C model, aprox '92.  The early C models were set up like the 9's with the flap on the side, when they went to the flat back the upper tank was relocated.  Interestingly most of the flat back buses that I have been around, including 30+ in our fleet just have a pump similar to a 12 volt "house" rv water pump, however my personal DL3 motorhome does have an "auto" refill.  I don't like that at all and need to rewire it so that it only works with the switch.  Any domestic rv water pump will work, if I remember correctly the originals were 24 volt, but we convert most of our fleet to 12 volt to buy cheaper pumps.

[daveola]

Why are you not a fan of the auto refill?  Seems like a nice feature.

And did you rewire the entire system to 12V, or just the coolant pump?  And if so, are you running 12V from the battery bank all the way to the back of the bus just for this pump?