Question: I drained the Alde and the drainage was pink. What does that mean?

Mellow_Yellow

Background: I'm the 2nd owner of a 2014 T@B 320 S that was garage kept for 4 out of the last 6 years. When I inspected the Alde reservoir tank, the fluid was yellow and 1/2 way between min/max levels. The Alde service record was blank, so I assumed it had been running on 6+ year old glycol. I bought the T@B from a dealer who does not know Alde's, did not check the Alde reservoir, or perform any maintenance on the Alde. The Alde was 'working' before I drained/flushed/replaced the fluid today. 
Problem/Question: When I drained the Alde - by opening the clamp and removing the brass plug behind the driver's side wheel - the fluid that drained out was pink. I tilted the trailer towards the back to make sure it was empty and confirmed that the reservoir was empty. I flushed the system by adding a cup of new Century TF-1 fluid to the reservoir and that drained out yellow. My main concern is that the original fluid was pink and I'm not sure what that means. Was there cross contamination? Did the old fluid change colour? Had someone used pink anti-freeze and then topped it up with the correct yellow fluid? Is that why the fluid in the reservoir was yellow, but the fluid in the system was ping? Should I assume things are ok now?
Current Status: After flushing, I put the brass plug back in and refilled up to the max line with just over 1 gallon of Century TF-1. I have the Alde running and am going out to check how it's doing and to top it up to the max line, if needed. I feel more confident that the Alde is in a known good state and that we'll be ready to take that T@B out for a shake out trip soon. 

Mellow_Yellow

Update: I found this on an RV site, which might confirm my findings.
"I just confirmed with International Thermal Research (ITR) that the Century Chemical TF1 Transfer Fluid will change from a greenish yellow color to a caramel color over time."

Sharon_is_SAM

@Mellow_Yellow - thanks for sharing that info.  First we have heard of the color change.  That was old glycol.  

ScottG

Century also makes TF-1 in a red version. Best as I can tell, there is no difference in the chemical composition. Seems unlikely that is what got into your Alde, though, since the stuff in the reservoir was still green.

CrabTab

@Mellow_Yellow I think you figured it out correctly, just old fluid. The antifreeze changes color when the rust inhibitors wear out in a car too. Good job making it right! Another thing for us all to be aware of...

Mellow_Yellow

Thanks for the reassurance @CrabTab , @Sharon_is_SAM and @ScottG! It's a great feeling to have brand new glycol in my little Alde. It is much easier to maintain than I imagined it would be, especially with the special hose clamp pliers! Like someone said on this forum: it's not a rocket

Mellow_Yellow

I have since learned from @ScottG , @pthomas745 , @TabbyShack and others that draining the Alde in the driveway only drains about 1/3 of the fluid. So today, I did I second 'partial drain' of the system and attached a photo that shows a dramatic difference among (left to right): partially drained 'original' 7-year old Alde fluid, today's partial drain of semi-replaced 7-year old Alde fluid and new Alde fluid.

As discussed on this thread: https://tab-rv.vanillacommunity.com/discussion/2665/changing-out-the-alde-fluid#latest, I plan to do this partial drain yearly and if my travels take me nearby an Alde service shop, I'll hopefully, one day, get a full drain.