Reader ‘shocked’ by brake-flush recommendation
Q: Regarding your recent column on brake fluid flushing . . . what a scam. They want you to change your oil every 5,000 kms, flush your radiator, flush your transmission, flush your brakes, flush your power steering. All are driven by the automotive repair industry. Flushing your transmission might cause damage when it was good. I’m shocked you recommended a brake flush. You’re either crazy or work for the industry.
Cliff
A: Thank you Cliff. Let me assure you that I provide recommendations based on years of experience repairing vehicles and providing information to professional automotive technicians in the best practices of maintaining and repairing vehicles. I have worked in the auto industry in the past but, according to my friends, they don’t think I am crazy. I do agree that there is up sell by some in the automotive repair industry but when I recommend flushing the brake fluid in a vehicle every couple years, it is based on saving the owner money in repair costs over the long-term ownership of the vehicle. If you are going to re- place the vehicle every three years, then you may not perform this type of maintenance but then you are passing on the repair costs to the next owner. In my experience, well-maintained vehicles with documented service maintenance will sell quicker as used vehicles and sell for a higher price than similar vehicles without maintenance performed regardless of their mileage or age.
Radiator coolant flushing is another example of good preventive maintenance. There are many dissimilar metals in modern vehicle cooling systems and these cause the break down of the coolant over time. The coolant actually acts like a battery electrolyte and produces a current that will corrode components, typically eating through the radiator core as a first sign. This is a change from most vehicles in the ’60s and ’70s that used mostly cast iron and brass in their cooling system components. Flushing the coolant will reduce the possibility of a roadside breakdown and expensive tow and repair.
I do not recommend other flushes such as power steering system, transmission and engine flushes. Power steering flushes should be done only if you are replacing hydraulic components in the power steering system that put debris in the fluid. Transmis- sion flushes can remove varnish and loosen particles that sometimes stick in valve bodies, causing transmission problems. Changing fluid in the transmission is different than flushing it, and usually recommended for vehicles that see severe duty service or towing applications. Engine flushes will help clean internal engine components but performing regular oil changes will do the same thing. Proper maintenance will reduce total ownership costs, not increase them.
Q: My 2010 Toyota Rav4 has been running fine but when I started it last week, the amber warning lights for the engine, 4wd and stability control all came on at once. The vehicle is running fine. A friend has a scanner and checked for codes. He found a P0442 code for an emissions system leak usually called the ‘gas cap code’ and he cleared the code. All the warning lights went out and have stayed out. My question is, if this is an emissions code, why did the other two warning lights come on? Debbie
A: Code P0442 sets when there is a small air leak into the fuel tank. This can be caused by a loose fuel cap or a bad fuel tank hose, seal or faulty evaporative emissions solenoid. The computer tests the system by placing a slight vacuum in the fuel tank and monitoring how long it takes for the vacuum to return to atmospheric pressure. If the vacuum doesn’t hold long enough, then there a small air leak in the fuel tank and evaporative emissions system. Often, the code is due to a loose or faulty fuel cap. Once the code is set, the computer has to retest the system a few times with no failure before it will automatically turn the warning light off, and this can take several days because there is a strict set of operating criteria that the vehicle has to meet before the system is retested.
When the code sets in the engine computer, it turns on the check engine light. When there is a problem in the engine computer, it automatically disables the stability control because the computer may not control it properly, and this turns on the Stability control warning light. When the stability control is disabled, so is the 4WD system, so that light comes on too. Clearing the code will turn all three warning lights off.