50,000 miles and five years

The TuxJeep now has 50,000 miles on it and is five years old. It seems like yesterday that the silver demon forced me to bring it home, but no, it's been five years. So I'm starting to change out all the fluids, just on general principle. First up was engine oil, which had about 6,000 miles on it (max 7500 mile change interval on this engine). This weekend I swapped out two gallons of coolant for two gallons of 50/50 Zerex G-05 HOAT and distilled water, just to start the process of refreshing its anti-corrosion properties.

Now, a note about anti-freeze. There's basically three kinds of antifreeze out there. The first kind is the old-fashioned green shit that has to be changed every year and which causes deposits in your radiator if you mix it with anything other than distilled water. This is what's available at your local Wal-mart. The second kind is the GM OAT (Organic Acid Technology) coolant, which is dyed orange, which has a bad tendency to eat pot metal parts of your engine such as the thermostat housing. This is *also* available at your local Wal-mart. The third type is a hybrid, HOAT, which has silicates to protect pot metal but also has the long-lasting organic acids to combat corrosion of the other metals in your engine. Ford and Chrysler have settled on this one for their new cars, both use Zerex G-05 HOAT coolant, dyed yellow for Ford (and for the aftermarket), pink for Chrysler. (Yes, *PINK* -- there are sources on the web that say that Chrysler's HOAT is dyed orange like GM's OAT, but the factory fill in my Jeep was quite blaringly PINK). Unfortunately only professional auto parts places like NAPA and Carquest, or dealerships, carry the HOAT coolant -- unlike the OAT or the green shit, you can't get it at Wally World or Auto Drone. And it's *expensive*, $15/gallon at NAPA...

So why is this important? Well, first of all, don't put the orange shit into your car unless that's what your car came with. OAT works by allowing the metals to corrode, then bonding with the corrosion to form a film. Thing is, some metals don't corrode with the correct chemistry for OAT to bond with to create the anti-corrosion film, and you end up with Bad Things Happening. So only cars designed for OAT (i.e. with the correct metal alloys exposed to its cooling system) should get OAT. But if your car came with OAT, you should stick with OAT for one good reason: all other chemistries will, over the long term, clog up your radiator and cooling system with silicate deposits. Only OAT is guaranteed to never do that, for the simple reason that it has no silicates.

Secondly: For everything else, HOAT is the correct thing to use. I've talked to people who restore old cars. To a man they recommend HOAT for *everything*, because it stops corrosion without unduly clogging up your cooling system and is safe for *all* metals, not just the ones that OAT chemistry was designed to bond with. Which is why any shop worth its salt should have only two coolant types in its quiver: the GM Dex-Cool OAT (orange), and the Zerex G-05 HOAT (yellow). The green shit should be consigned to history along with leaded gas and carburetors, it just doesn't work as well as the new stuff. Yet the green stuff is still the most common coolant even shops put into cars... despite the fact that it's crap. But it's cheap. Which is all that counts when someone cares more about profit than about their car's lifespan.

So anyhow I scored some Zerex G-05 (yellow) for about $5 a gallon less than the pink-dyed MOPAR HOAT at the Chrysler dealership (pink), so now have kind of pinkish-yellow coolant in my Jeep (since the cooling system holds a total of about 2.65 gallons and I put a little less than 2 gallons of coolant into it, the rest was in the heater core and other places in the cooling system). Note that the G-05 *IS* the MOPAR coolant, Zerex simply dyes it pink rather than yellow. It seems that pink is a stronger color than yellow, so 3/4th gallon of pink makes 2 gallons of yellow pinker than you'd think. Curious, eh? So anyhow, mixing G-05 with G-05 should be fine, I just refreshed the anticorrosion package with my infusion. Since I only changed out around 2/3rds of the coolant with the radiator and reservoir change, I'll go ahead and do it again in around three years, since I put around three years worth of anticorrosion additives in there with the new coolant.

Next thing I did was change the front differential fluid. I had two quarts of Royal Purple 75W140 left over from my last differential fluid change, and used that. What I discovered inside the differential was that the old Royal Purple fill had sludged up a little since my last change of the front differential fluid, at 20,000 miles. So this is the last time I'm filling with the Royal Purple, the next fill is going to be the Mobile 1 75W140 synthetic. I've already purchased the Mobile 1 plus the limited slip additive for the rear differential and will be changing that out shortly.

Some other fluids that can be changed:

1. Brake fluid -- probably the most important one to change. Chrysler uses low-spec DOT 3 brake fluid. Going to DOT 3/4 should get me better specs as well as get rid of any moisture that's accumulated in the system over the past five years. I have a Mitey-vac vacuum pump somewhere, I need to find it (haven't used it since I moved to the "new" place eight months ago)...
2. Transmission fluid -- this uses Synchromesh fluid. Chrysler doesn't even have a fill spec on this, it's supposedly a "lifetime" fluid. Probably going to leave this alone for now, and change it at 90,000 miles just on general principles.
3. Transfer case fluid -- this uses ATF+4 automatic transmission fluid, which is good stuff (much better than the old GM Dexron III from days of yore). It's spec'ed to be changed at 80,000 miles. Won't hurt to change it anytime between now and then.
4. Power steering fluid -- this, alas, got changed last year when the moron ran the red light and broke my steering box with the side of his car. So I'm fine there.

So anyhow, that's pretty much all she wrote for now. I'll change out the rear diff fluid sometime in the next few weeks, find my pump and turkey baster and suck the old fluid out of the reservoir, replace it with fresh, and then bleed the brakes to suck the old DOT3 out and put the better DOT3/4 fluid in, and then I'm pretty much done maintenance-wise for the moment.

Oh, while I was at it I put some new light bulbs into my lights. But I'm not telling you what they are, because they're a bit, err, not DOT-certified. But at least I'll be able to see at night!

-- Badtux the Blindingly Bright Penguin