Coolant level?

[Tic Wilson]

RE: 05 Beaver, CAT C9 400 or 3126 engine.
There is a large "plastic" container at the rear of my engine compartment, that has a radiator type cap on it.  The container is also marked with lines indicating max-min.  I can see a dark stain near the bottom and above the min line, and by inserting a wooden dowel, I have convinced myself there is actually fluid in there, but I have never seen a change.  Does not seem to increase with running, nor drop.  What is this reservoir for, and does it require a speciality CAT fluid for replacement? 

[Edward Buker]

Tic,

It sounds like an expansion tank for the antifreeze system. If that fluid does not expand and fill when the engine gets hot then it is likely that the antifreeze is low enough that with expansion does not overflow and never reaches the container. A photo of the container would really help here.

Until you are sure what fluid this container was meant to contain I would not add anything to it. Your coach manual should have a diagram that shows each fluid check location and should help here.

Later Ed

[Tic Wilson]

Thanks Ed.  That is what I suspected.  I will get a photo posted in a few days.  In the meanwhile, I found an interesting write-up:
http://www.motorhome.com/rv-how-to/rv-tech-tips/what-you-need-to-know-about-diesel-antifreeze-and-coolants/

[David T. Richelderfer]

Here is a recent picture of an engine coolant expansion tank with a neat little added device to see the coolant level at a glance:

http://beaveramb.org/forum/index.php/topic,4768.msg35696.html#msg35696

I liked this added device so much I added one to my expansion tank.  A couple brass fittings with a short piece of tubing and a few tools is all it takes.  I made mine a bit longer.  On mine the tubing shows the coolant level from about the MIN line to well above the MAX line.

[Tic Wilson]

So this was the photo I promised.  Replacement fluid that should be used?  The level is still above the minimum, but I want to be prepared to add fluid if needed.  I like the sight fix suggested.

[Edward Buker]

Tic,

If the fluid is pink/red in color it is most likely an approved long life diesel antifreeze like Cat ELC. Kind of a purplish color it could be Cat regular antifreeze. I think you need to check out the color and see what it might be. Best case is pink/red Cat ELC or equivalent. Greenish yellow might be standard Prestone antifreeze which would be unapproved for this use. You can get a piece of plastic tubing and drop it into the tank bottom, put your finger over the end and pull out a sample to put into a clear container to check out the color.

Whatever it is you would like to know it is diesel approved and is hopefully an ELC type. If is a non ELC you would need to get a test kit to determine the SCA level (coolant additive for diesel) and adjust it.

Later Ed

[Steve Huber Co-Admin]

Pink or red color could also be the fluid with SCAs pre-added (not ELC). Not sure how to tell difference from sample except by analysis.
Steve

[Tic Wilson]

Thanks to all for your input.  One final question:  Explain how to have the fluid analyzed and where is this done?  At a Cat dealer?

[Edward Buker]

Tic,

You might have some service records in the coach that might tell you what was used antifreeze wise. Cat dealer could get analysis done and may be able to sort out what is in it. If it was standard anti freeze they could check the SCA level and add supplement if needed. If not they may advise to change it out and replace what is in it with Cat ELC which would be a good move for the long run.

Later Ed

[Steve Huber Co-Admin]

Tic,
Ed's right as I have no idea where one would get it done so starting at Cat shop good option. One other option would be to buy a gallon of each (O'Reilys sell a Fleet product with SCAs added ) and see if you can compare to what's in your coach, but analysis would be a better way.
Converting to ELC is fairly straight forward. Number of good threads on this on Forum. In short; cap ports where SCA filter hoses enter engine. No need to remove hoses. Just cut them off. Drain existing fluid. Refill with water, run engine till warm. Drain water. Repeat this 4 times. Last time, use distilled water. After draining, add 1 gallon of straight ELC. Refill remaining with 50/50 ELC and distilled water.
Steve

[Bill Borden]

Ok, you have my attention.  A sight glass would be a fantastic addition to the Surge tank.  It seems that I either stick something in the surge tank, like my finger or guess with a flashlight, to see the level.

So adding a sight glass is an awesome idea.  So I searched for a Diesel coolant surge tank sight glass and this is one of the ones that I found.  The tank on my Coach has an unused port that I can screw a sight glass into, hopefully it will be a the right level or close.

][http://www.northernfactory.com/MD-HD_TRUCK_AND_BUS/DRAINCOCKS_-_SIGHT_GLASSES/RW0009-4]

There are few styles, but most of all they are mfg for Coolant surge tanks.  A sample picture is attached.
One is on the way.
 

[Steve Huber Co-Admin]

Bill,
Consider adding a coolant recovery tank. You can get one at Auto Zone for < $20. Simply route the existing overflow tube into the recovery tank and add new overflow hose from the recovery tank. You not only can see coolant level but it makes adding coolant a lot easier.
Steve

[Bill Borden]

Hi Steve,

OK, I have thought about adding the recovery tank too.  I have seen reference to it in the Forum.  But I have some question's regarding this addition. 

Does this now means that the Surge tank becomes part of the total volume of the coolant capacity and the Surge tank now becomes a holding tank that is full at all times, then the over flow bottle is kept at half full?

Also, I read about lowering the pressure release of the radiator cap on the Surge tank?  To keep the pressure lower on the ever cracking Surge tank that I replaced once while on a trip to Arizona.   

It sure would be an improvement on adding the coolant to the surge tank, what a poor design.

Final question, any thoughts as to the size of the recovery tank?

Thanks for the good suggestion, this is something I have had on my to do list to change for some time.
 

[Edward Buker]

Bill,

I have gone to the lower pressure cap and it has saved my surge tank, mine is still the original. The external tank in Steve's photo holds about a quart. It saves you sending coolant on the ground from the original surge tank is full and expands. It does become part of the surge system but it is still hard to manage the level.

If you fill the main tank enough to surge into the small tank then there is not a lot of volume to play with in the small tank before that will overflow. I tend to keep the main tank about half full cold and use my finger through the original surge tank cap to test the depth. You can add to the added extra tank and some will be siphoned up into the main surge tank while cooling but it is hard to be sure where the coolant level actually is in your system from the remote tank.

Later Ed

[Steve Huber Co-Admin]

Bill,
Ed covered most of the answers. The added recovery tank probably holds about .5 gallon. Most have a Hot and Cold level markers just like on your auto. I fill mine to the Cold marker with the surge tank full.  Switching from the 13 to a 7 lb cap will help the surge tank last longer. The 425 HP C12 runs cool enough that the resultant lower boiling point won't impact  you.
Steve