DrD123

very true - most folks don't realize you should replace the anode periodically (sort of a pain, as it's close to the length of the water heater tank, so if you have the tank mounted such that you don't have space above it to pull the anode an insert a new one, replacement really isn't feasible. Water tanks are often coated on the interior as well, which helps, but as with any corrosion mitigation coating, just buys you time. It's the "why" we are looking for here - looking for facts/data, not opinion.

Goodness, if you are going to get in on the fun, at least read the whole thread! He said "Oxygen has to be present for corrosion to happen. This is why boats and planes at the bottom of the sea can be preserved for 100's of years. There is very little oxygen at deep depths." - now, maybe I'm over simplifying, but that sure sounds like water is not the problem, dissolved oxygen is, and that he appeared to be aware of the difference...

Nope. Wrong! Ok - seriously, pick any corrosion text - I even showed you a nice one by Uhlig and Revie you could grab on amazon - there are tons more of them out there. Oxidation refers to the change in the valence state of the material being oxidized - the metal being oxidized looses 1 or more electrons, and the specie being reduced gains electrons. You can reduce water, you can reduce hydronium ions in solution, as well as a myriad of other things - you do not need oxygen (dissolved oxygen in solution) to act as your cathodic reaction. Pick up an actual corrosion book, or read a chemistry text, basically any peer reviewed technical resource on the topic - listening to folks that literally have no clue what is going on just isn't helping you. Oh, this will be fun - define the "electrolysis reaction" as used in that article for me, please. The ASM handbooks are great - you want to actually read them though. Realistically, 13A would be a better one for you as it deals with the fundamentals. I'll go out on a limb and say you didn't cough up the money to actually read it, though. except not in the way you are thinking - they are going to a non-aqueous solution of some sort, which is also a high impedance solution - if you go back to the description I gave you on what you need for a corrosion process to go, in addition to needing an anode (material to be oxidized) and a cathode (surface where reduction is taking place) you need to connect those via both an electronic path (through the metal) and an ionic path (through the solution) - if you can deal with corrosion by eliminating any of those parts - with a high impedance electrolyte, you effectively kill the ionic conduction path, breaking the loop. You can accomplish the same thing with coatings (blocking the surface) and many film forming/adsorbing inhibitors accomplish a very similar effect by adsorbing onto active sites on the active metal surface, effectively coating it. it's one of the things they mention (they actually don't say it's one of the primary things - they say "A number of conditions in a cooling system will affect the degree and rate at which metal surfaces corrode. These include: coolant pH, the concentration of dissolved oxygen and carbon dioxide in a coolant, metal surface deposits, metal stress, coolant temperature, acids formed in the combustion", but you knew that... they list a variety of things, all of which can contribute. Dissolved oxygen is important when it's there as a cathodic reaction (it's thermodynamically viable at lower potentials than many other reactions) but it will be rapidly depleted in a closed system with lots of reactive surface around. Once it's depleted, other reactions will become thermodynamically viable (water reduction, as an example) - you really don't understand corrosion. That one was just painful to look at! If you want conference papers, there are a number of conderences out there you could pull from (the annual NACE Corrosion conference (though since NACE merged with SSPC, it's going to be the AMPP corrosion conference), eurocorr, MS&T is adding more and more sessions on corrosion - there are tons of them. Also lots of journals to take a look at - there you'll find actual peer reviewed publications, instead of inane marketing crap (there are tons of them - the AMPP Corrosion Journal, Corrosion Science, Electrochimica Acta, Journal of the Electrochemical Society, etc. - there really are tons of them) - you won't usually find introduction to corrosion papers there, though - your best bet are really corrosion textbooks.

Just going to say that's taking "well, while I'm in there I might as well replace..." to a whole new level!

I think the bulb/LED is the same, but from their website, for both the driver is hardwired to the bulb (no idea how easy it is to open/remove/replace) and the driver definitely looks different (and is labelled differently on their website) - they also some other stuff that comes with it - a second harness for each side, along with an anti-flicker/error cancelling resistor. The new ballast looks like you could disassemble it, but there could be adhesive in addition to the screws. regular version - https://www.vleds.com/shop-products/led-headlights/micro-limited-9005.html DRL version - https://www.vleds.com/shop-application/application-high-beam/9005-low-voltage-daytime-running-light/micro-limited-9005-low-voltage-daytime-running-light.html

In the cooling system, the corrosion rate might be low because of the corrosion inhibitor package in the coolant... just sayin' It will corrode just fine without any dissolved oxygen. adding dissolved oxygen will give you another cathodic reaction, so absolutely can exacerbate things, but it's not needed. Corrosion of the internals will absolutely take place without oxygen ingress. But hey - let's pull on that string a little - how much oxygen do you suppose gets in when you take the cap off the container? Is uptake and mass transport really fast? Rumor has it some guy named Henry has a law that might help you calculate that sort of thing in part... Wrong. Sorry. Seriously, stop talking about stuff which you literally have a child-like knowledge of - read a book - here's a decent intro to corrosion text - get this one https://www.amazon.com/Corrosion-Control-Herbert-Uhlig-1985-01-18/dp/B01N6KSL2Q Seriously

Please, child, read the whole article - perhaps pay attention to the statement "Oxidation-reduction reactions are now defined as reactions that exhibit a change in the oxidation states of one or more elements in the reactants by a transfer of electrons" - hell, they even write out a couple of reactions for you (those are the scary looking equation things) - they even have an example where there is zero oxygen needed - iron in an acidic solution. (iron goes into solution as ferrous or ferric ions, depending on the electrochemical conditions - there is no corrosion product on the surface because iron in solution is the stable specie - the cathodic reaction is the hydrogen evolution reaction (reduction of H+ in solution to form H, which recombines to form H2 gas) Nope - absolutely not the case. Sorry dude - you literally have absolutely no idea what you are talking about. If you are so intent on proving me wrong, why not pick up a basic corrosion text and do some book 'learnin! (well - or not, since you'll learn that I am right...)

Seriously? Please do look up the dunning kruger effect, and understand that your level of "knowledge" in corrosion/corrosion science is probably best described as "child-like", or in terms of the D-K effect, you are what they describe as someone who is "incompetent" - I'll even give you a wikipedia article to help you out, since I am guessing mentioning the effect is just whistling right over your head... https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect gotta love a definition which uses the word as the definition - those are particularly informative! Since you seem to be fond of google-searching for science, let me help you - here's a high level explanation of redox processes as they might apply to corrosion (it's pretty incomplete, but like I said - I googled you up some knowledge - I even kept it simple for you by limiting the search to 2 words - metal oxidation - and picked something off the first page) https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_-_The_Central_Science_(Brown_et_al.)/04._Reactions_in_Aqueous_Solution/4.4%3A_Oxidation-Reduction_Reactions Exactly - and you just keep on doing it - let me be the first to tell you that you literally know just about nothing when it comes to corrosion/electrochemistry (my basis being your responses above) - you have a child like understanding at best. Let me explain to you what's annoying - when folks whose experience base is literally a short time doing something completely different (you said you've been wrenching for 10 years or thereabouts, so we'll use that as the "short time doing something completely different" - hell, you even bragged about it) feel their basic understanding in that area means they are somehow knowledgeable in another unrelated area, and then try to argue in that area. It would be funny if it weren't so sad.

Not surprising - MSRP for subaru parts for the timing belt, tensioner, four idlers (2 big smooth, 1 small smooth, 1 cogged), water pump, and 2 gallons of coolant is $848.13 - add other common sense items (plugs, serpentine belt, thermostat, and random other little bits) and you are around $950 in parts... they can probably bang most of the job out pretty quick, but the water pump is way more of a pain on your GT than the Outback. What did they quote for the clutch?

I have had their micro evolution extreme LEDs for my low beams for a little over a year and a half - they are great. They have said something like this (the DRL one) was coming for a while now, so I check every now and then.

Well, I think we have a contender here... looks like VLEDS has released an LED bulb which instead of running full power all the time, the beams run at 800 lumens when they see DRL voltage (<10V) and full brightness (2500 lumens) when they see normal operating voltage... (this is different than the pulse-width modulation solution which has been available for a bit - these are specifically for constant voltage applications) Seriously considering this set... https://www.vleds.com/shop-application/application-high-beam/9005-low-voltage-daytime-running-light/micro-limited-9005-low-voltage-daytime-running-light.html

I agree - I'd use a sleeve as well. So the scratches are just at the outer edge of the sealing surface? If they go all the way across the flange, would you need to fill them with something, or maybe sand them smooth so the sleeve can seal?

I'm certainly not throwing stones - I was pointing out we had no data to support the assertion that the stuff was bad (only opinions/stories that hypothesize why it's bad), and that all we have was the OEM stating the conditioner is a requirement (they don't list it as optional in any of the service manuals - it's literally step 1, put in the coolant conditioner) - we definitely don't have any info on Subaru's rationale for requiring it, either.

Well - flew for the first time since the start of the pandemic - things seem to be more or less getting back to normal (the airports were crowded and all my flights were packed) - masking is mandatory in the airports and on the flight (compliance was very good, as far as I noticed) - anyone else travel yet?

If I were in grad school, I would definitely take some liberties with the analytical equipment in the lab and do so - hell, I probably could have convinced my advisor it was a good idea and done so with their blessing - however, running personal stuff at work is more than sort of frowned upon. It gets annoying when you have so many folks that are just going "don't use it because it's a bad idea" or "I know it's the same as product x because... well, I just know" and so on. Lots of hypotheses/stories that are more or less compelling depending on who tells them, but zero hard data.

Sorry - been on vacation for 3 weeks in New England You absolutely, positively do not need oxygen for corrosion to go - you need 1. an anode/anodic reaction - that's the corrosion/oxidation reaction 2. a cathode/cathodic reaction - that's the reduction reaction that supports the oxidation reaction (here's a spoiler - oxygen reduction is just 1 of a gazillion different possibilities) 3. an electrical path between the anode and cathode (these can be separate regions on the same metal surface, or in the case of galvanic corrosion, will be the electrical contact between the two parts, and why electrical isolation is key when dissimilar metals are used together) 4. an ionic path between the anode and cathode (that's through the coolant, in this case) for the oxidation reaction, please try and remember that oxidation refers to a positive change in the oxidation state of the metal (so from Al metal to Al(3+) as an example for the cathodic reaction, you can reduce dissolved oxygen (tends to be dominant reaction in aerated aqueous solutions) or you can reduce water, or reduce ions in solution (e.g., the hydronium ion is usually the one in acidic solutions, can also be reducing other metal ions in solution, organic ions in solution, etc. - there are a myriad of potentials, depending on what happens to be thermodynamically viable in the solution) So once again, unless you live in some screwed up fantasy land, you do not need oxygen for corrosion to go, or for oxidation to take place (again - oxidation doesn't mean forming an oxide) and inside your engine absolutely, positively is a place where you can get corrosion without any dissolved oxygen - you only need the water (reduce the water - H2O + e- -> H + OH- - often referred to as the hydrogen evolution reaction, or HER) Why you are suggesting it's a "special case" where oxygen isn't needed for corrosion is beyond me - perhaps pick up a corrosion text and do some book learnin' Working on cars does not even kinda sorta prepare you for a debate on corrosion science. (your comments sort of scream Dunning-Kruger effect... just sayin')

Glad you got it sorted. Amazon is getting better, but there's still a lot of counterfeit crap on there.

Did the rpm drop go away, too? You should try cleaning your old one and see if it functions properly after that (always good to have a spare!)

Not arguing if it's good or bad, or debating anything, really. Simply indicating Subaru says as step one for every single engine they make is to add coolant conditioner when replacing the coolant. That's a strong statement from a company that has a lot to loose if they screw it up. Trying to find actual data to support that it's helpful or not, and can't seem to get past a couple folks continuously spouting opinions about why it's bad, and that it has to be a specific Holts product because some youtube guy said it was. Is anyone saying that? Subaru is definitely saying you are supposed to add it whenever you change the coolant in every engine they make - every single one. In terms of does Subaru care about their customers, I would think any manufacturer that values brand loyalty, etc. cares quite a bit about their customers. If the chemistry of the conditioner isn't proprietary, please, provide the data! Opinions (biased or not) are great, but ultimately just that. Data actually answers the question - be it empirical evidence of damage caused by the conditioner, or benefits brought by the conditioner, or analytical data showing it's the same as whatever product your internet person says it is. (in your video, they even point out it's a different size container - so with the radweld, you add twice as much to a system as subaru wants you to add of the conditioner, apparently)

So if you weren't posting the image to suggest they were the same product because they were both in a blue container from Holts, why exactly did you post it? so? You thinking subaru makes any of their chemicals? oil, coolant, etc.? Not likely - almost all are going to go to a manufacturer that does that sort of thing, and order up something that fits the bill for what they need. In this case, Subaru used holts, who makes a variety of their own products - it's certainly possible the conditioner is one of those, and equally possible it's a custom blend of stuff - without data, we don't know. Pretty much all modern engine oil looks very similar out of the bottle - is it all the same? You really need something more quantitative than a visual assessment to answer the "is it the same" question.

yeah - when it comes to long term reliability, I'll go with a manufacturer who actually pays the price when things fail over a mechanic - sorry - they design and have to guarantee long term reliability of the system. Subaru, the manufacturer and one standing behind the vehicles, is recommending it in every single engine they have produced for 20+ years. Nice try - you absolutely, positively do not need dissolved oxygen to support corrosion of aluminum in water - you only need the water (water reduction will support aluminum corrosion just fine). Plus, in a system with other reactive species in it, there are other cathodic reactions besides oxygen reduction which would likely play a major role, anyway. Without delving into solution chemistry and flow rates, suffice to say there are other things going on in the ocean, and absolutely you have heavy corrosion of both iron and aluminum in the ocean, even deep (there's always a heavy corrosion product layer when things are recovered). Delving further into your nonsense, coupling aluminum to other metals, particularly more noble materials like steel - is particularly bad - without isolating the materials electrically, or using proper inhibitors, significant galvanic corrosion of the aluminum will result - again you need no dissolved oxygen for it to go - the water is plenty. (if you want more info, pick up pretty much any corrosion textbook and read)

For an aging system, it's not at all uncommon for corrosion inhibitor demand to increase, either due to corrosion initiation within the system that wasn't effectively suppressed by the original inhibitor package (in most closed systems, you monitor and add inhibitor as the system operates and the inhibitor is consumed or decomposes - obviously you can't do that in a car) - also, when doing a drain and fill, you never really get everything out, so there would be some residual stuff in there. Were it me, for a low maintenance system like a car cooling system, I would be inclined to make similar recommendations for a reduced time period. Exactly! It would be great to have either an analysis of the products or even empirical evidence showing damage to the system that can be conclusively demonstrated to be from the conditioner

Well, since literally all of their products are in the same container, some of them blue, some black, etc., that tells you absolutely, positively nothing.

as posted above, in a coolant system where someone added the conditioner, while there was some guck in the overflow, the coolant system was clean upon disassembly so your argument is that aluminum doesn't corrode in water with a low dissolved oxygen content? that, I am afraid, is 100% incorrect. There are a number of other viable cathodic reactions that will support corrosion in a deaerated system (even in 100% pure, zero dissolved oxygen water, corrosion can go on aluminum - there are other metals where it can't - copper being one, but aluminum will corrode just fine). The oxygen introduced by an air bubble is going to be somewhat small (considering the size of the bubble, the number of things that will consume oxygen as it makes its way into the water, and the relatively slow transfer rate into the water) was there decreased cooling system efficiency? seems unlikely you'd film the inside of the radiator - it would more likely collect at dead spaces/reduced flow regions, I would think - would be really cool to see actual data/images... if the coolant system were all crapped up, and lots of folks with blown engines were seeing that, it would get attention - just like other pattern failures - and given how litigious our society is, there would eventually be some enterprising lawyers who put together a class action suit. It's called out as a requirement for literally every vehicle Subaru has sold for the past 20 years or more! Seriously? I listen to data, which is what I was hoping would come out of this thread - I spoke about opinions earlier in the thread.

How do we know it doesn't? adding air wouldn't deplete a corrosion inhibitor, but air+heat (well, oxygen+heat) could get a leak preventing additive to start to agglomerate, but it would likely take more than just a little air+heat to do that. (in terms of bleeding, I've found the 5th gen to bleed very easily - filling, squeezing the upper/lower radiator hoses to push out bubbles, then close it up, fill the overflow, and the system will let out any residual air after a trip or two, then just fill the overflow bottle back up to full and you are good to go. Blown up from the conditioner? If the conditioner were the issue and killing engines, one would think there would be a class action suit similar to the spun bearing one for the WRX/STi with the EJ25... if the conditioner were gumming things up, causing overheating, etc. it should be pretty straightforward to see that, then Subaru would be in a pretty tough position since they specify it for all of their engines...