Coolant and ATF fluid changes on Toyota

I'm not sold on an oil simply because it is touted as "synthetic". It's a buzzword at best for products sold in the USA. I even have a hard time believing that the best, highest quality base synths are really orders of magnitude better in terms of durability than conventional.

Couldn't agree more. Also, none of the filters I've taken out of any Toyota are anything more than a screen, which basically traps catastrophic chunks from going into the pump, but does nothing for particulates of friction material and tiny (normal) bushing/steel wear particles. In terms of filters and servicing, I like the domestic transmissions for their fiber weave filters. They sure seem to last a long time if you service them (and a really short time if you don't) despite the many pattern failures virtually all domestic trannys suffer form design inadequacy.

You know that's the case when every interval of the maintenance schedule for ATF reads "inspect". 420,000 miles? Inspect! Oh, the unit failed? Replace!

That goofy setup is the worst I've ever seen implemented. You have my condolences :-)

same time; it appears to be coincidence that these two design features are shadowing each other. GM has been offering "sealed" (I prefer dipstickless as it is more accurate but awquard to say) four speed transaxles for quite some time now.

MNo kidding! You can't get it from the top, so you have to get under the car (heavy-duty ramps and a creeper) and reach your hand up over and around a couple things, take it off, go above and get a LOOOOONG funnel, and then reverse. Time to punch an engineer in the nose!!

Built_Well wrote:

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John, that's a great article, but the reason the Toyota extended-life pre-mix pink coolant showed "a substantial weight loss (corrosion)" in the lab test is that the test was performed on radiators and heater cores made of * copper brass * and which used lead solder (in other words, old-fashioned, cheap radiators and heater cores).

I don't think the modern * aluminum * radiators and heater cores that Toyota uses, for example in the Camry, have any copper brass and lead solder in them at all. Ray O can correct me if I'm wrong.

Regarding the 2-EHA acid that GM's DexCool uses, Toyota is staunchly opposed to using 2-EHA in coolant. The 2-EHA is also not fast-acting. The article states that 2-EHA is "very stable and lasts a long time" but it "takes thousands of miles to become fully effective in protecting coolant passages." It's actually the phosphates that are used in Toyota's coolants that are fast-acting, not 2-EHA. According to the article:

"Extensive Japanese tests have shown phosphates to be a good corrosion inhibitor for aluminum, and particularly effective in protecting water pumps from corrosion after cavitation erosion/corrosion."

As stated before, I have not experienced any "loose bolts" aka pulling threads out of the block on anything past mid 2003 models. There may be a wide spread issue with it that I haven't seen on newer models, but the odds aren't that great. There was a "silent" improvement in the newer blocks that AFAIK took care of the issue. I don't have any way of knowing if something will become a recall. Yes, the helicoils are as quick as it gets and a quality repair to boot.

Whew...

What should I be paying attention to?

I am a little low on coolant, but I haven't added any in almost 3 years...

Sorry, Ashton. The ethylene glycol or propylene glycol can oxidize, in time, upon contact with air or oxygen, especially at higher temperatures. Reaction by-products are acids like glycolic, oxalic.

This is one of the reasons that coolant formulations have an alkaline buffer.

In this type of situation, that is true. The National Association of Corrosion Engineers defines corrosion as any process which results in the deterioration in properties or strength of a material. Manual processes such as erosion are included even though these are not electrochemically driven.

It could be disastrous to have galvanic couples between copper or brass, and aluminum.

There are a lot of problems with the organic acid inhibitors. Protection of aluminum can be an especially difficult problem, as DexCool users found out. The Hybrid OAT technology reintroduces silicate, at lower levels than in the green formulates, which was one of the few efficient inhibitors for aluminum.

Phosphates or phosphate esters can work miracles in some systems, particular where steel is involved. And, it doesnt take much to do the job. I havent tested some of the newer phosphate ester chemistry against aluminum, and cant comment.

I'll accept that as true. However, it's a moot point since whatever you do that wrecks the glycol is going to wreck the corrosion protection way before the loss of glycol becomes a problem. Which brings it back to my point, you should go mostly by miles, with time a secondary consideration.

Miles or operating hours, it is a moot point with me.

You may remember the old reliable Nalcool 2000 product was a dark red in color. That was due to phenolphthalein, IIRC. When the glycol oxidation caused the pH to drop below about 8, the product cleared up to a colorless or light yellow liquid, indicating it was time to change.

Nowadays, the colors are, I guess, just there to warn the consumer that he should stay with the product that the car producer supplied.

Hype reigns supreme with some of these products and their marketing.

Helicoil usually isn't the best for high stress situations. For head bolts and spark plug holes, usually a solid insert, like Time-sert

is used. But for the Toyota 2.4L engines, I heard some questions as to having enough metal to put in a Time-sert. However, heard people Time-serted with good results.