How to tell when the old Rhomar Fluid has been replaced by the New Rhomar Fluid during the exchange

CST_B320

Two years ago, I removed the old yellow Century fluid from my 2019 T@B320S, flushed out the old century fluid with 16 gallons of distilled water, disassembled everything, cleaned the corrosion from the bulging pipes, painted the ends of all the pipes with Bill Hirsch Miracle Paint reassembled everything (Per Mark Turney's Videos) and added new Rhomar fluid.  I am happy to say 2 years later no more bulging hoses. Everything looks great, a big Thanks to Mark T. and the research he did. 

When adding the Rhomar, it was easy to see when the system was full, as the colored Rhomar filled the exit bucket.  Now two years later I will be pumping out the old Rhomar and replacing it with the new Rhomar.  Is there any way other than measuring the volume going in and out, that can help me determine when old is out and the new is in?   Has the old Rhomar changed color over the last two years?   I think my T@B 320 holds about 2.5 gallons of alde fluid and I would like to save what's left for topping off as needed over the next two years.      

qhumberd

I have not dealt with the new Rhomar in my 2019, but I would say that a flush with distilled water is not a bad idea, if only till the fluid appears clear (maybe 5 gallons or so). Then refilling with fresh Rhomar and you can easily see the color change, then give it a bit more for good measure and you are done.

Really glad to hear your procedure worked to prevent corrosion. Wonder if just the coating and keeping the Century fluid would have had the same result? I have had 2 flushes in the 6 years of my 2019 and have stayed with Century. No apparent bulging but I can't see all my loop either. My Alde with the Flow has worked flawlessly from the get go.

CST_B320

Appreciate your thoughts on a reflush with distilled water.  I'll sure consider it but then I have more fluid to dispose of at the recycle center.  I want to keep the replacement simple and fast.  Last time it seemed to take forever. 

The Century fluid may still be OK to use and it's less expensive.  I would just check to make sure the rubber tubing is clamped at the ends of each of the pipes to give your a better flow.  When Nucamp built mine, they pushed the tubing all the way in as far as it could go and clamped it at the end of the tubing creating a pocket and backflow which I think caused the bulging, especially where the fluid entered the radiators.  

As far as visually checking for bulges where you can't see, I highly recommend purchasing Borescope to electronically view the ends of the pipes.  They have a camera and light source at the end of the cable which can be bent in any direction to view and take pictures in tight places.    

qhumberd

I think once you have done the flush the next time it is a lot faster. My latest flush and refill barely took me an hour and I had only around 10 gal of used fluid and distilled water to handle. Its a pain but only every two years a least. I just checked the Rhomar/Alde antifreeze fluid and it is nearly 3 times the cost of the Century. I'll update the forum if I find bulging after this camping season on my inspection but 6 years in and it all works fine.

The Borescope seems like a great addition for more than just the Alde as well.

pthomas745

The only time the "flush" has ever been mentioned in the glycol change is if you are changing from the "old" glycol to the "new" glycol. If you are just changing the same glycol back, I don't see why there has to be a "flush" at all.  If you are concerned about that, just run an extra half gallon of the glycol through the loop and be done.

CST_B320

Thanks to both of you for your suggestions.  I think I'll just run 3 gallons of new Rhomar thru the Alde and call it good for the next two years.