Surge tank coolant level

[Joel Weiss]

I noticed the other day that when my engine is cold I have no coolant in the surge tank of my C12.  Honestly, I don't know how long this has been the case.  The tank is very clouded and difficult to see through but I can see that there is a small amount of coolant in the bottom which would indicate that coolant does get into the tank when the engine is hot.  There is no evidence of any coolant leakage and the engine holds 190 degrees on the Silverleaf under virtually any condition (the highest I've ever seen is 194 for a moment or two).

I wanted to check on what the level should be when cold before simply adding coolant.  The system was drained, flushed, and filled with ELC 6 months ago.  Once I get some guidance I'll go to a local CAT dealer and buy a gallon or two of ELC.

[Edie and Marty Hochberg]

Joel,

I am not answering your specific question, however you mention that with the almost opaque coolant surge tank it is hard to see the coolant level.  I had the same condition until the tank was recently replaced.

I found by using a high intensity flashlight with a narrow beam after dark allowed me to quickly and easily see the coolant level.  The trick is to shine the light into the tank from behind.  Then move the light up and down.  When the light beam is above the coolant level the entire tank above the coolant will glow.  When the light moves below the coolant level the glow will stop.  With a small flahlight you can easlily and accurately gauge the level plus/minus 1/2 inch.

Hope this tip helps

[Gerald Farris]

Joel,
There is a relatively clear area on your surge tank with a gauge to show the cold add mark, however it does you no good since it faces the engine. The surge tank on your coach comes from a Ford product, and in the application that it was originally for the viewing area faces out instead of in like it does on the Beaver application.

I use to run 1 to 2 inches of coolant in the bottom of the tank when cold until I made some changes in the system design. Now the surge tank is full all of the time because I added a recovery tank to the system. I also changed the original 13 PSI pressure cap and replaced it with a 7 PSI cap because of repeated surge tank failures. That subject was discussed in a thread in February 2010.
  http://forum.bacrallies.com/m-1265574499/s-0/highlight-coolant+surge+tank+cracks/

Gerald

[Dick Simonis]

Joel,
There is a relatively clear area on your surge tank with a gauge to show the cold add mark, however it does you no good since it faces the engine. The surge tank on your coach comes from a Ford product, and in the application that it was originally for the viewing area faces out instead of in like it does on the Beaver application.

I use to run 1 to 2 inches of coolant in the bottom of the tank when cold until I made some changes in the system design. Now the surge tank is full all of the time because I added a recovery tank to the system. I also changed the original 13 PSI pressure cap and replaced it with a 7 PSI cap because of repeated surge tank failures. That subject was discussed in a thread in February 2010.
  http://forum.bacrallies.com/m-1265574499/s-0/highlight-coolant+surge+tank+cracks/

Gerald

Gerald, you wouldn't happen to have a pic of your coolant recovery installation by any chance.  This seems like a great way to resolve the issue.

Thanks

[Joel Weiss]

Joel,
There is a relatively clear area on your surge tank with a gauge to show the cold add mark, however it does you no good since it faces the engine. The surge tank on your coach comes from a Ford product, and in the application that it was originally for the viewing area faces out instead of in like it does on the Beaver application.

I use to run 1 to 2 inches of coolant in the bottom of the tank when cold until I made some changes in the system design. Now the surge tank is full all of the time because I added a recovery tank to the system. I also changed the original 13 PSI pressure cap and replaced it with a 7 PSI cap because of repeated surge tank failures. That subject was discussed in a thread in February 2010.
  http://forum.bacrallies.com/m-1265574499/s-0/highlight-coolant+surge+tank+cracks/

Gerald

My surge tank appears to be intact at present.  when I bought CAT ELC to top off I also took your suggestion and purchased a 7 psi cap.  

Since we both have C12's I assume our operating parameters are about the same.  Mine runs a nearly constant 190 degrees; the highest I have ever seen is 194 for a few moments.  My calculations indicate that even at an altitude of 10,000 feet a 7 psi cap would still provide a boiling temperature of water at 220 degrees so there should be no risk in using the lower pressure cap.  I, too, would be interested in the details of your coolant overflow system.

[Gerald Farris]

I will try to take some pictures and post them latter.

Gerald

[Dick Simonis]

I was just outside looking at the coolant tank and notice that there are 3 hoses connected to it.  One is what must be the overflow just under the radiator cap, one is another small hose that runs across the tank then heads forword to an unknown destination, and the 3rd is the large hose that drops down to and engine driven accesory which has another large hose heading forward.

Question is, where do these all go and what is the function of whatever it is that is mounted on the engine.  My first thought was a water pump but that doesn't seem to make sense.

A whole lot to learn about these C12 engines.

[Edward Buker]

Gerald,

I like the idea of an extra visible small surge tank and will look forward to the photos. I was thinking that the mounting level should be above the current tank which is a bit of a trick.

Dick,

I do not remember where the hoses go from the surge tank exactly but you are right about the overflow. The other small line will usually tie in high on the water jacket, sometimes thermostat housing, and is an air bleed back to the tank that allows the water jacket to fully fill. The main hose just ties the water jacket to the surge tank as a main supply. It is not always easy to see and follow these lines in our RV application.

Later Ed

[Gerald Farris]

To install a coolant recovery tank, I had to find a container that would work in the area that I wanted to mount it in. Since I could not locate a factory made tank that would in the area that I wanted to install it in, I used a heavy one gallon polyethylene windshield washer jug and drilled a hole through the cap for the hose. The hose from the surge tank will need to reach to or very near the bottom of the of the recovery tank to function properly.

I then used 1/8 inch steel plate (overkill, but that is what I had handy) to make a shelf for the recovery tank to sit on. I then bolted the shelf to the steel crossmember and secured a piece of strap steel with two screws to the wood above the crossmember to hold the tank in place when traveling.

Gerald  

[Joel Ashley]

Just be glad you don't have 5 tank connections like mine, Guys!  2 small hoses on top, large one to the cooling system on the bottom, a sensor on one side, and the overflow tube.  

On the other hand, one helped saved my bacon on I-5 once.  Just under the minimum fill line on the side of the tank is mounted a sensor that alerts the driver via Check Engine on the dash if the tank level gets below the line.  The coach goes into self-protect mode upon a low-coolant situation, and loses power.  A very long cracked feed hose from the tank had lost enough coolant to set off the sensor;  this on a 5 month-old coach!  Fortunately we were on our way to Harrisburg for a scheduled faulty windshield replacement, and had to be towed less than 20 miles.   (Hats off to CoachNet for the advice and direction over the phone diagnosing the problem for a greenhorn new diesel coach owner).

The Monaco tech replaced the hose with a higher grade, custom-built one he had locally made, and redid all the hose routings which he deemed poorly configured and mounted at the factory.

Earlier models may also have the aforementioned sensor, perhaps hidden behind the tank?  Heck, I may have more connections back there myself - I never looked   .

-Joel

[Edward Buker]

Gerald, thanks for the photos....

A man after my own heart.....take some left over parts and make something good out of it that works better than the original.

I was thinking that the surge tank needed gravity to work and it had to be mounted higher than the current tank but I guess  the liquid forces that are created by heating (expansion) as well as cooling (contraction) are enough....that simplifies things.

Later Ed

[Gerald Farris]

 Ed,
The recovery tank does not have to be above the surge tank, however if it is below the tank like mine is, your pressure cap on the surge tank has to seal very well on the filler neck because there has to be enough vacuum created to draw the coolant back into the surge tank as the coolant cools.

The closer you get to level the better, but I did not have a good location to mount a recovery tank that was level with the surge tank.

Gerald    

[Dick Simonis]

Gerald, thanks for the pics they are very useful.  Question though.....looking at the first pic, what is the object directly to the left of the coolant tank that looks like it's mounted on the wall.  Must be a Marquis thing as there is nothing there on mine and we both have a C12.

I think I can mount an expansion tank on that inboard wall and/or even hang it from the screws that hold the upper sound insulation in place.  Tomorrow, I'll visit an auto parts store and see what they have  for an aftermarket tank that might fit in that area.

I have to admire how you built something from nothing.

[Dick Simonis]

Well, I just couldn't help myself. The post and pics from Gerald inspired me to take a day off from golf and do the expansion tank.  Went to the local auto parts place and picked up an aftermarket tank for $17.00 and mounted it on the panel behind the shore power cord reel....perfect spot.

I haven't change the thermostat yet but will the next time I go to town.  When my neigbors leave, I'll fire up the engine and try to get it up to temp.

[Gerald Farris]

Dick,
In your last post, you said that you had not changed the thermostat yet.  Is there a specific reason that you are going to change the thermostat, or were you referring to the surge tank pressure cap?
If you change the thermostat, I would recommend that you use a Caterpillar thermostat only.

Gerald