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Improper fluid transfer

Friday, February 4, 2011 - 01:00
Here’s the RAM. It’s a nice truck, but “poor fuel economy” on this ride is the is the order of the day, especially with the worn tires, brush guard, etc.

I grew up in rural Alabama, and during those early years of my earthly existence, as I moved around the community trafficking with my friends on a red Welsh pony. The old timers with whom I was acquainted tended to share all kinds of information that I, as a young boy, felt was superfluous. The local country store still had tongue-in-groove plank floors, walls and ceilings, and every drop of gasoline was full service. Cell phones and personal computers were sheer science fiction. Gatorade was brand new, came in cans, contained cyclamates and was nestled among the other ice cold drinks in the Coca-Cola refrigerated drink box. The farmers (old and young) sat around the cool top heater in ladder back chairs with woven bamboo seats (even in the summer) that faced down the aisle to the doors leading out to the gas pumps.

Occasionally, one of these old men would hold up a rusty and oddly shaped piece of farm tack from the days when mule and horses pulled plows and hay rakes, challenging me to draw on my eleven years of life experience to identify whatever it was. May my ancestors forgive me, I wasn’t interested, nor was I impressed. And when I began working with grease and steel, those same old timers would talk about the glory days when cars still had the headlights mounted above the fenders instead of in them, every engine was a flat head, wheels had spokes and so on. They’d joke about the old Fords not needing brake fluid because the brakes were mechanical on those old buggies. Well, Henry Ford’s first ride had a steering lever instead of a wheel, too, but those days are gone (at least until cars get joysticks for steering).

It didn’t take engineers long to realize just how simple it was to build hydraulic systems to operate the brakes. And if you could snake a steel line to a hydraulic slave unit (wheel cylinder or caliper) with some pressure modifications for vehicle weight distribution, then use leverage, stroke, and a disparity in input and output piston sizes, a car could be stopped effectively without mechanical linkage.

This is the fluid puddle in the brake booster. The new booster came unpainted, so we washed it with brake parts cleaner and painted it black.


Fluids transmit movement by their incompressibility, but they also can facilitate heat transfer by convection. They absorb it from a hot component and, when moved by a compressor or pump, carry it to an exchanger, as in the case of coolant or refrigerant. Engine oil is a fluid that cleans, lubricates and operates hydraulic components like lifters, diesel injectors and chain tensioners, and provides cooling as well. Power steering fluid can, in addition to its obvious purpose, provide power brake assistance and on some vehicles it drives hydraulic cooling fans. The one unifying element of using fluids to do work is that the fluids must be contained. Today’s article explores the problems created in two particular vehicles with problems that directly resulted from fluid making its way from where it was supposed to be contained to areas where that particular fluid doesn’t belong.

The Expedition
This customer had a problem with a power loss/flashing MIL, which, even to newbies, means a Type A misfire. Translation: While the PCM generally shuts the injector down on the guilty hole, the catalyst conceivably could be damaged if this condition isn’t corrected. She bought the Expedition used and had taken it to her mechanic a couple of weeks earlier. He told her he had replaced either A coil or THE coils, she wasn’t sure which. Well, this one had coil packs instead of coil on plug, and neither coil pack assembly looked new; they were far dustier than they should have been from two weeks worth of driving. While he could have replaced the pack with a used one, from the price she had paid, she had shelled out enough money to have purchased a new coil.

Connecting the EASE Wireless Vehicle Interface to the Expedition’s DLC, I retrieved three codes – both banks were perceived to be running lean and the No. 4 cylinder was misfiring. Well, it isn’t smart to go after lean exhaust codes when a cylinder isn’t firing. All bets are off on the O2 sensors until every cylinder is doing its part.

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