2014 S Maxx
2011 Tacoma 4cyl ... edit: 2022 Tacoma 6cyl - oh yeah!

A_Little_T@b'll_Do_Ya




Using a variation of the @Dalehelman shop-vac method, I was able to extract 7 quarts of old glycol from our 2018 320S.
Other reports I’ve found so far involve different models (CS-S) or vintages (2015). I know the layout is similar, but I was curious if anyone with a more recent 320S has successfully used the vacuum extraction method - and if so, how much glycol did you get out?
Ramon
I followed the same basic procedure, but instead of a spare vacuum wand I used a “1-1/4 in. x 12 in. White Plastic Slip-Joint Sink Drain Tailpiece Extension Tube”, cut down to 8” so it could more easily be maneuvered into position given the tight space. (Most stores also carry a 6” long version, but this can fall completely into the expansion tank and then is a PITA to fish out - ask me how I know this). The wider, threaded end fits loosely into the recessed bottom of the glycol expansion tank. To make a seal, I added a basin gasket I found at Ace Hardware, “Danco Rubber 1-3/8 inch D X 2 inch D Mack Basin Gasket”. The 1-3/8” ID fit tightly around the wider end of the extension tube, and the 2” OD seated well enough onto/into the bottom recess of the tank to provide a seal under vacuum. I left the threads on the end of the extension tube to prevent the gasket from being pulled down and off when removing the tube from the tank.
The narrow end of the extension tube fit into a short length of 1-1/4 ID clear vinyl tubing, and the other end of the vinyl tubing fit onto the shop vac hose (mine uses 1-1/4” attachments).


It still took a lot of contortions to get everything in place, but it worked OK.

After the initial rush of fluid, it kept coming up in dribs and drabs for quite a while so I just kept it running until it was down to just a few drops.
If/when
I ever do this again, I would try adding a 90 deg elbow to the extension tube (or maybe
just use PVC pipe instead) to make positioning easier and reduce the rise that the fluid has to travel.
To fill, I used a “Slippery Pete" hand pump which worked great. After 3 or so cycles of filling to the max line and burping with the circulation pump speed turned up, the gurgling stopped and I felt the system was full. It took a little over 7 quarts, which matched what I got out. I had three gallons of the Century fluid so I refilled with that - hopefully there will be more clarity on how and where to get the switch to Rhomar done properly when it’s time to change again.
Ramon
Thanks for the info @fstop32 . I had bought into the notion that the shop vac method would evacuate all of the fluid from the system, in part because I reeeaaally wanted it to work. But if your 2.5 gal figure also applies to a stock 2018 320S configuration, then I really only got ~70% of the old glycol out, which would be a bummer.
Does anyone have concrete info on glycol capacity with the more recent 320S models? @BrianZ?
In hindsight, I should have at least opened the gravity drain to check if there was still any residual fluid left in the boiler and other driver-side plumbing before doing the refill. Regarding the hoses and convectors on the passenger-side of the system, I can’t think of a way to confirm with certainty that those are empty without actually disconnecting hoses.
I guess if you were going to flush with distilled water as the next step, then the color of the flush water would also give some indication of how much residual glycol, if any, was still present after the initial vacuum step.
What are others' thoughts on this?

Yep. Same idea!trimtab said:^ sounds like when I used to change brake fluid...
If you read his previous posts, he discontinued the third convector when he reassembled everything.BrianZ said: