Alde Fluid Never Changed - Problems?

Golferv · February 8

Looking for advice!

Looking to purchase a Nucamp T@B 320. Found a 2018 Tab 320 and when inquiring with the owner about last time Alde system was flushed he indicated it has never been flushed since he purchased it in 2019. How concerned should I be? Will non-maintenance cause inoperability or system issues that would be costly to repair?

Owner says they have only used unit 8-10 times since they purchased it. Unit is priced good and looks good. Priced a couple thousand below what others are asking. Would have to travel a couple of hours to transact deal.

I’m not handy and any repairs would have to be done at service system.

Is it worth gambling on.

Thanks
DZ

AnOldUR · February 8

The anti-corrosive properties of the glycol degrade more over time than use. That's the reason for a two year time frame rather than the amount time the Alde actually ran. Look for bulging around the convectors like in the attached picture to know if you have a problem. If you don't see bulging, you are probably safe to assume that all it need is a glycol exchange (preferably to the Rhomar fluid).

Golferv · February 8

AnOLDUR - thanks for the reply.

So glycol sitting for 5 years is OK in the system as long as the convectors are not bulging?

And, where do I locate the convectors?

thanks

NorthIsUp · February 8

We purchased our 400 in mid-2018 (with the same system as yours) and finally changed the fluid (to the new Rhomar) in 2023 with no valid reason for the delay. Technician said that the Alde was in fine shape and it ran well last summer (2023) and recently.

Time will tell for us, but just take care of it after you buy it. You have an honest seller. See if it works now heating water and providing heat. Decide after that. Also, we agree with @AnOldUR and that should do it for you.

AnOldUR · February 8

Golferv said:

So glycol sitting for 5 years is OK in the system as long as the convectors are not bulging?

It's not OK, but if there's no bulging you may have been lucky. The convectors are in a couple of places, but the one's under the back bench seat are the easiest to look at.

Golferv · February 8

AnOLDUR - if they are bulging are we looking at replacement of entire system, just the convectors, or ???

thanks for your replies. I do appreciate it. I’ve got a couple hours drive tomorrow and wandering if it’s a big deal or not to overcome. And how much added expense it could be.

AnOldUR · February 8

@Golferv it really depends on how bad the corrosion is. The amount of bulging is an indication, but you'd have to remove the hose to know for sure. If you do see bulging like the picture above, I'd insist on a professional looking at it before purchase. If everything else is to your liking you could ask to hold back some of the payment until the situation is remedied.

Here's an example of a bad one, but it could be even worse ...

Image: https://us.v-cdn.net/5021717/uploads/editor/vb/x87e3kc77zms.jpg

Golferv · February 8

a AnOLDUR - thanks so much. So the bulging is in the black tubes in the first picture? Or the silver fan like pieces to the right.

FYI - I called Alde and spoke with a rep and he said the glycol will crystallize over time and cause etching in the tubing? Not sure exactly what that means.

ScottG · February 8

While there are numerous theories regarding corrosion at the convector stubs, the problem does not appear to be well correlated with "old" Alde fluid.

I confess I neglected changing my glycol for over six years. I had some minor corrosion... but so did owners who had changed their glycol religiously every two years. In terms of things I could evaluate (appearance, odor, pH, specific gravity) the six-year-old glycol was identical to the brand new glycol that replaced it. My tenth year with the T@B is pending (again overdue for a glycol change--haha) and the system continues to function perfectly.

To be clear, I'm not advocating neglecting glycol changes, just suggesting that the frequency of those changes is probably not a reliable indicator of the Alde's condition.

If you are particularly interested in this topic, grab a tumbler of your favorite beverage and buckle in. There are some extensive discussions here you might find useful, starting with Changing out the Alde fluid and its spinoff Corrosion of Alde Convectors.

Welcome to the forum, and good luck with your purchase. Please let us know how it turns out.

AnOldUR · February 8

Yes @Golferv, the bulge will be in the rubber tube, not the aluminum. The corrosion of aluminum is what causes the bulge. What Alde said about crystallizing over time is interesting. I hadn't heard that before. Did he say what the time frame for this to happen was?

Golferv · February 8

@ScottG thanks. I’m wavering in my decision. The unit is a few hours away from me so I’m debating on driving over, inspecting (don’t really know what I’m looking for - other than bulging) and making a purchase decision. I’d hate to spend $XX,XXX and then have to spend $X,XXX on the Alde system.

Golferv · February 8

@AnOldUR - the Alde rep kinda caught me off guard. I did not think to ask what time frame this happens in. I guess it’s like most manufacturers they like to stick to the book.

Citruscountytab400 · February 8

I full time in a 2020 tab 400 and I've never changed the fluid. I do add a little bit during heating season, but I also test the ph and heat/freeze temp a few times a year- which is perfect. The more you use the unit, the less likely the fluid will degrade as fast as a unit that is only used a few times a year.

It's very similar to a car and having to do more frequent maintenance on a car that is heated and cooled over and over, but never brought up to operating temperature and allowed to burn off moisture within the oil and other fluids.

Golferv · February 8

@Citruscountytab400 thanks for your insight/experience. Glad that’s worked for you. From a buyers standpoint, deferred maintenance is a red flag. The unit I’m looking at has a couple of other issues that lead me to believe things may have not been kept up.

pthomas745 · February 9

There are a lot of moving parts to the "glycol issue", as you can see in this thread. Keep in mind the ideas in this group about the glycol and the corrosion issue have been worked out with the collaboration of the people in this group, FB members, and even with ideas and help from Airstream owners, who also have the Alde systems.

You will notice that there is nothing (zip, zippo, nada, nil) from Alde or NuCamp about this issue. Except, change the glycol every two years, and then the sudden change from the Century TF1 glycol, over to the "Rhomar" glycol, which happened in Dec of 2020. We also do not really know if NuCamp/Alde were improving their installation practices over the years that prevent the "holidays" of the glycol leaking underneath the poorly placed clamps that have been noted over and over in the earlier model years. We have learned a lot about the "heat transfer fluids" used in various trailer manufacturers, and learned that there "appears" to be not a dimes bit of chemical difference in any of them.

So, some owners blame the glycol entirely....and that might not be true at all. In a couple years, the owners here who have cleaned their corrosion and stayed with the Century glycol, and properly sealed and clamped the various hoses in the trailer, will be able to come back and tell us what they find: did proper hose installation and clamping prevent corrosion? We will see.

The bottom line: this group can help you with cleaning the corrosion, if you find some and need to do it. I'm in the middle of cleaning mine, and the process was not hard, even for a "not very mechanical" type like me.

But: take a good look at the photo above. If you see that much "bulging" of the hoses, you will need to clean the convectors and probably some of the small aluminum connectors of various hoses.

The worst case is the aluminum has been eaten all the way through, and is leaking at the hose clamp ends. One of the things we have learned is the Century glycol "flouresces" under a black light. So, if you have access to a black light flashlight, it might help.

Yoshi_TAB · February 9

In a couple years, the owners here who have cleaned their corrosion and stayed with the Century glycol, and properly sealed and clamped the various hoses in the trailer, will be able to come back and tell us what they find: did proper hose installation and clamping prevent corrosion? We will see.

Also, in a couple of years we will find out if the change to the blue/green glycol has any effect on the corrosion issue. This is still TBD. It's been 3 years since the change (Jan. 2021). Five years will be a good milepost.

pthomas745 · February 9

@Yoshi_TAB that is entirely true. I would really enjoy tearing a newer Alde hoses and convectors apart and having a good look at the parts and the clamps, etc.

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