Subaru coolant conditioner... yes or no?

Ok - so the owners manual doesn't mention it, but the service manual has as step 1 to add the coolant conditioner to the radiator before pouring in the coolant...

 

 

Searching a bit, some folks say it's already in the Subaru super coolant, but others raised the question if it's already in there, why does Subaru say to add it in the service manual?

 

 

 

Getting ready to do my timing belt, and have two gallons of Subaru super coolant ready to go... debating on whether or not to add that as well...

when I replaced my radiator and thermostat, I just used the subaru super blue. 2yrs later and I've had no issues

No. It was a band-aid fix for the well documented head gasket problems on the EJ253 before they finally switched to MLS gaskets just a couple years before retiring that engine. If you insist on using it, this is what it really is...

 

https://www.holtsauto.com/holts/products/radweld/

Edited May 31, 2021 by Plastixx

I know holts makes it, but are we sure that's the product? (has anyone done an analysis or is it just that's a holts bottle, and there is a holts product for radiator sealing, therefore that's it?) Subaru still has it in their service manuals all the way through 2020 (maybe beyond, but that's the latest issue I have for anything) for all of their engines - EJ, FA, FB, and EZ.

I know holts makes it, but are we sure that's the product? (has anyone done an analysis or is it just that's a holts bottle, and there is a holts product for radiator sealing, therefore that's it?) Subaru still has it in their service manuals all the way through 2020 (maybe beyond, but that's the latest issue I have for anything) for all of their engines - EJ, FA, FB, and EZ.

 

I posted the wrong product link earlier so I edited it, but yes it's been confirmed countless times that it's Holts Radweld. You can find endless discussions about this subject online. Use it if you want, but watch this video first...

 

 

Feel free to watch the whole thing, but I timestamped the part that covers your question.

I have also found lots of folks whom have speculated (in that video, he is very clear that he's speculating) what it is based on where it's from - the radweld stuff comes in larger containers. Also - the radweld stuff is supposed to be added to the expansion tank (at least that's what is on the Holt's website) whereas this is supposed to be put directly into the radiator, and not the expansion tank (holts actually has a bunch of products - radweld, radweld plus, and wondarweld - first is radiator and hoses, second is entire coolant system (calls out cylinder heads, etc.) and the third is supposed to be for cracks in the block) - doesn't mean it's definitely not it, but there are enough contradictions from the folks selling the stuff vs. subaru to make me question folks that speculate...

 

One difference that has caught my attention is that the subaru coolant conditioner specifically indicates that it contains corrosion inhibitors, whereas the radweld product definitely does not... doesn't mean the conditioner doesn't have leak stopping stuff, just that the product literature indicates it has at least one other thing in there...

 

It's certainly easy to see the bottle, look on their site and find a product that sounds like a match, and run with it, but there's no msds, no tds or any other info that I have been able to find for the coolant conditioner, which is odd - Holts has SDS info on their website, but there are multiple different radweld listings (along with the radweld plus) and the SDS only really gives you hazardous or otherwise listed ingredients, so lots of room for other stuff. The useage instructions from subaru for the conditioner and holts for their products are both specific, and different. So I am inclined not to listen a whole lot to folks that speculate based on the appearance of the bottle. Hell - it's even possible that when the campaign in the early 2000's happened, it was to address something specific, and the product makeup then could be different than it is now (manufacturers absolutely change chemical compositions without telling the buyer - I deal with the repercussions of that sort of thing all day long at work)

 

As an engineer, I'm really looking for actual data - either empirical (coolant system failure clearly resulting from the additive) or compositional (wouldn't put it past someone to reverse engineer it a bit - wouldn't be a whole lot of effort at all for an enterprising chemistry grad student with access to the right equipment to run the material - were I still in grad school, I totally would have been curious enough to run this to ground) or something along those lines.

 

A manufacturer indicating it contains specific things and requiring it in the service manuals for all of their engines is a pretty strong statement... they have way more to lose than random folks on the internet speculating!

One difference that has caught my attention is that the subaru coolant conditioner specifically indicates that it contains corrosion inhibitors, whereas the radweld product definitely does not...

 

Well, now you're the one speculating because it definitely does contain a corrosion inhibitor in the form of phosphoric acid.

 

Specifically mentions it has anti-corrosion properties...

https://www.holtsauto.com/holts/news/radweld-work/

 

Proof in the pudding...

http://www.servicebest.com/downloadable/1831589_EN.pdf

DO NOT use the conditioner.

 

It will only make a mess of your cooling system. It will not help or prevent any issues.

Ok - so the owners manual doesn't mention it...

 

The 2011 owners manual specified the coolant change procedure and addition of coolant conditioner starting on page 11-18. My head gasket gave out at 59k miles so I’m in the camp adding the conditioner to give it all the help I can.

Well, now you're the one speculating because it definitely does contain a corrosion inhibitor in the form of phosphoric acid.

Well, phosphoric acid is not a corrosion inhibitor for aluminum, so not really speculating on my part, and it's presence in the msds is proof of, well, nothing - also, there are three different radweld chemistries listed in the msds listings from the Holt's site (go to their site, scroll to the bottom, click on SDS& regulations, then search for radweld under product name) - one has phosphoric acid, and others don't, but many do have long chain organics that could be considered corrosion inhibiting (as film formers on the metal surface), or certainly not corrosion exacerbating - given the concentration, I would guess the phosphoric is there as a pH adjuster during formulation, but who knows.

 

Sorry "speculating" triggered you for some reason, the guy in your video says he's speculating on the rationale, and bases his assessment on the product id on the shape and color of the bottle...

The 2011 owners manual specified the coolant change procedure and addition of coolant conditioner starting on page 11-18. My head gasket gave out at 59k miles so I’m in the camp adding the conditioner to give it all the help I can.

That's interesting! in the 2012 manual, it doesn't really say anything - for changing your coolant, they deleted all of the instructions and just say "It may be difficult to change the coolant. Have the coolant changed by your SUBARU dealer if necessary." so not real helpful! (it's definitely there in the 2011 manual, though!) However, in pretty much every Subaru service manual, for every engine through MY20 that I have it says to add it, so I think it's safe to say Subaru thinks you should use it!

It will only make a mess of your cooling system. It will not help or prevent any issues.

I'm trying to see if anyone has found issues like that, but haven't come across anything - did you have your coolant system messed up by it? If you have seen others report the same and can share the links, that would be great!

 

Nothing really jumped out at me as something that's definitely going to crash out of solution on the msds listings, but they only are going to mention stuff that's hazardous (well - they can list more, but that's all they have to list) - the video above indicates they think it's ginger root, but that's not on the msds forms, nor would it have to be as it's non-hazardous

Well, phosphoric acid is not a corrosion inhibitor for aluminum, so not really speculating on my part...

 

I never said it was. For someone who claims to be an engineer, it seems that you can't even interpret a datasheet. Look at it again, page 3, sodium hydroxide.

 

Anyway, I don't get why you insist on beating a dead horse. The debate on what the conditioner is was settled a long time ago. I guess your hubris has you believing you know more than everyone else who has looked into this over the last decade and a half or more. If you bothered doing any research at all you would have found plenty of info like this post...

 

https://www.vwvortex.com/threads/subaru-coolant-conditioner-clogged-my-radiator.5603480/post-76187657

 

As for your position of "if Subaru recommends it, it must be good". Well, ask yourself this; if Subaru was so great at what they do, then why would a "conditioner" need to be added at all? Why doesn't their super blue coolant contain the needed amounts of surfactants and corrosion inhibitors already?

 

I bet you're the type to go to the doctor with a problem and willingly take any big pharma pill they prescribe without question. The type of pill that has side effects nearly as bad as the alignment it's supposed to fix. An ailment that could be easily remedied by healthy life choices. Ah, but the doctor surely knows best.

 

Do what you want, I really don't care. I was only presenting info so you could make a more informed decision. I don't know why you even made this thread if you're so damned sure of yourself. I'm done here.

DO NOT use the conditioner.

 

It will only make a mess of your cooling system. It will not help or prevent any issues.

supporting documentation?

I use Amsoil Coolant, and have never had a problem in any of my turbo subies.

I never said it was.

Seriously? read your own post above

Well, now you're the one speculating because it definitely does contain a corrosion inhibitor in the form of phosphoric acid.

That sure sounds like you were saying it was a corrosion inhibitor...

For someone who claims to be an engineer, it seems that you can't even interpret a datasheet.

I absolutely am, and absolutely can interpret them - I'm thinking it's not me who has no idea what they are actually reading...

Look at it again, page 3, sodium hydroxide.

You have just got to be kidding! Sodium hydroxide (alkaline pH in general) is really, really bad for aluminum.

I guess your hubris has you believing you know more than everyone else who has looked into this over the last decade and a half or more.

Seriously? I'm not claiming it's good/bad - I was asking for data, empirical or otherwise, that shows it's a problem. You're the one getting all hot and bothered because someone didn't read your post and take it as gospel. I'm asking, and you're offering an opinion - opinions are like assholes - everyone has one, and they all stink. Hence - data!

if you bothered doing any research at all you would have found plenty of info like this post...

 

https://www.vwvortex.com/threads/subaru-coolant-conditioner-clogged-my-radiator.5603480/post-76187657

again - zero actual data - no pictures, nothing. You can find a gazillion posts where they say it did nothing, and a few here and there where they say it killed their car.

As for your position of "if Subaru recommends it, it must be good". Well, ask yourself this; if Subaru was so great at what they do, then why would a "conditioner" need to be added at all? Why doesn't their super blue coolant contain the needed amounts of surfactants and corrosion inhibitors already?

Don't know - that's a subaru question. All I pointed out is that they list it as step 1 for every engine in every service manual I have looked at through 2020. (Legacy, WRX/STi, Forester, and BRZ) That's a pretty strong statement from a manufacturer.

I bet you're the type to go to the doctor with a problem and willingly take any big pharma pill they prescribe without question. The type of pill that has side effects nearly as bad as the alignment it's supposed to fix. An ailment that could be easily remedied by healthy life choices. Ah, but the doctor surely knows best.

Wow - you really do have your panties all in a bunch! Insults and everything.

I don't know why you even made this thread if you're so damned sure of yourself. I'm done here.

Here's a thought - why don't you actually read what I posted. I am not claiming it's good or bad, necessary or not - just curious what other folks opinions were. All I have repeated is the info on the websites and datasheets.

supporting documentation?

 

I have been professionally working on Subarus for over 13 years.

 

DO NOT USE THE CONDITIONER!!!

I have been professionally working on Subarus for over 13 years.

 

DO NOT USE THE CONDITIONER!!!

So nothing, thanks.

I have been professionally working on Subarus for over 13 years.

 

DO NOT USE THE CONDITIONER!!!

Why? I'm just looking for data, one way or the other, that shows if it's worth doing. Lots of folks have strong negative opinions, others have positive. If it's so bad, why? Have you seen damage and can share images, etc. that show a failure because of the conditioner?

I've never had any other vehicle, or know of any other vehicle, that needs a "coolant conditioner".

 

So when Subaru mentions it, I wonder what it is and why. Research shows its basically a stop leak product.

 

Now why would a properly functioning cooling system need a stop leak added to it? I really cant see a reason why at the moment.

 

I dont buy the anti corrosion angle because Subaru specifies a pretty standard water/coolant mix with plenty of anti corrosion protection before, during, and since the introduction of the conditioner.

 

So I decided not to use the conditioner and havent seen anything out of the ordinary.

I've never had any other vehicle, or know of any other vehicle, that needs a "coolant conditioner".

 

So when Subaru mentions it, I wonder what it is and why. Research shows its basically a stop leak product.

 

Now why would a properly functioning cooling system need a stop leak added to it? I really cant see a reason why at the moment.

 

I dont buy the anti corrosion angle because Subaru specifies a pretty standard water/coolant mix with plenty of anti corrosion protection before, during, and since the introduction of the conditioner.

 

So I decided not to use the conditioner and havent seen anything out of the ordinary.

Only other instance I've come acrossed is Ford Motocraft VC-6. Maybe we have something in common with the infamous 6.ohhh s#it

 

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Only other instance I've come acrossed is Ford Motocraft VC-6. Maybe we have something in common with the infamous 6.ohhh s#it

 

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Not familiar with that engine...but the 6 ohh s#!t moniker kinda hints why it may need a "coolant conditioner" lol!

Not familiar with that engine...but the 6 ohh s#!t moniker kinda hints why it may need a "coolant conditioner" lol!

Referring to Ford's 6.0 turbo diesel

 

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The conditioner will gunk up your entire cooling system and cause it to underperform.

 

It was meant to combat the leaking headgaskets on the NON-turbo legacy's of the early 2000's. The common headgaket failures of these engines was caused by a chemical breakdown of the gasket.

The conditioner was a band-aid from Subaru to reduce the amount of warranty claims.

 

DO NOT PUT THE CONDITONER IN A TURBO SUBARU!!!

or any car...

I put cooling system conditioner in my GMC Syclone circa 2005. It made a mess off my overflow bottle within 1-2k miles. I pulled the motor apart in 2009 and I didn’t see any other signs of the condition. The cooling system was clean. I still have the original radiator installed on my truck and my coolant stays clean. (I did buy another overflow bottle because it bother me and it wasn’t easy to clean).

 

I did not used the Subaru conditioner when I did the timing belt and water pump on my 2012 GT. I kind of figure since pretty much all my coolant was drained that it wasn’t necessary. (I also had to do it twice because I forgot the gasket on the side of the water pump). I don’t used it on the 2011GT either when I did the headgasket. I did use OEM Subaru coolant for both.