Does "acid in the coolant" a reasonable diagnosis for a car with only 30,000 miles on it?

Dear Car Talk

Dear Car Talk | May 01, 2005

Dear Tom and Ray:

We recently had our family's 2003 Honda Odyssey in for the 30,000-mile service at a Phoenix Honda dealer. During the visit, the service adviser counseled us that the coolant system contained acid and would require a complete flushing, at a cost of $199. This was one of several recommendations, including replacing worn break pads. Since we plan to keep the vehicle and want to ensure a long life, we proceeded with the work. In spite of deciding to have the cooling system and engine flushed, we have not been satisfied that a car this new would have such a problem. Given that this car has only been serviced by the dealer and we have never added coolant, how could there be any acidic content? Thank you for your advice on this puzzling problem. -- Loren and Cindy

TOM: Why didn't he just throw in some Rolaids? That's what we do.

RAY: I suspect the dealer was trying to scare you guys. And unfortunately, it worked. You forked over $200 when you almost certainly didn't have to.

TOM: Acid IS the enemy of your cooling system, because acid leads to corrosion. And acids build up over time due to the interactions among the coolant, the metals in the engine and things like oxygen and other impurities.

RAY: But how long should your coolant resist corrosion before it needs to be changed? Well, Honda says 120,000 miles or 10 years, on this particular vehicle -- even under extreme conditions, such as the heat of Phoenix.

TOM: So, having acidic coolant at 30,000 miles would mean that something is terribly wrong. And while it's possible, I find it extremely unlikely -- especially since you've never had to add coolant.

RAY: So if your coolant is, in fact, acidic (it should normally have a pH of at least 8.5), you should insist that your dealer tell you what's wrong with the engine and why it's breaking down your coolant so quickly. And then insist that he fix it for you under warranty.

TOM: If he tells you that your acidic coolant is just due to normal wear and tear, you are then free to invoke the "bite me" clause, and go elsewhere for your service from now on. That suggests he's just trying to milk you for service you don't need.

RAY: This is a situation where a second opinion would have been the thing to do, guys. And if someone tries this again at 60,000 miles, that's what we would recommend.

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