Improper fluid transfer

Jan. 1, 2020
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 refrige
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.

As you can see, we got quite a lot of fluid out of this booster.

My mind shifted to the years I spent at the Ford dealer. When I focused my attention on the rear of the passenger side of the engine compartment, I noticed that the heater hose clamp that is directly above cylinder No. 4 was brand new, as was the hose. A lot of you guys already know where I’m going with this one. With the light trained on the spark plug wire boot beneath that hose, the tattletale coolant stain was painfully evident. The clamp looked tight, but with the inevitable rise of pressure in the cooling system, a drop every few minutes is enough to compromise the electrical integrity of that particular spark plug and its boot.

With the spark plug wire removed from its well in the cylinder head, we removed the No. 4 spark plug to find it a greasy wet mess, as was the spark plug boot. It’s easier for the spark to travel through this wet stuff than it is for it to punch through compressed air and gasoline molecules in the combustion chamber.

With the spark plug and wire replaced, the hose clamp tightened (who knows why this clamp tends to be loose, but we saw a lot of it on brand new vehicles at the dealer), we repaired a couple of minor vacuum leaks and got the fuel trim readings back on track.

For a mild digression, let us state that when fixing any kind of concern that is believed to be causing fuel trim problems, it’s wise to remove the battery cable or disconnect the PCM so as to let it forget the numbers it had stored. And while a throttle body/IAC passage cleaning may be in order to get the idle quality back up to snuff, the fuel trims will start at zero after the memory dump. If they stay there when it goes into closed loop fuel control, you’ve fixed the problem. If, however, short fuel trims start swinging back toward the previous correction (whether positive or negative), then you aren’t done with the repair, and it may be time to break out the smoke machine.

This hose is dreadfully prone to ruin a spark plug, a wire or a coil on plug if the clam isn’t good and tight.

When George first called me about his truck, his concern was fuel economy and power related (Dodge RAM with a 5.9L isn’t a fuel miser anyway). Our initial test drive and inspection revealed nothing particularly noticeable. The transmission fluid needed changing, and scan tooling the datastream revealed a sluggish oxygen sensor, which, if its signal settles into a .6 volt malaise can cause a Dodge to buck and jerk due to faulty fuel trim reactions. We replaced the O2 sensor, along with some well-rounded spark plugs that scope tested with a lot of resistance – they had been in that grand old 360 since it rolled off the line. The RAM had a freshly cleaned air filter in the box, and the fuel pressure was normal. We checked and se tire pressure, but the boots on this truck pretty much had walked their limit and probably weren’t rolling very freely. Further, the grille was sporting a brush guard, which tends to shave off a mile per gallon or two because of wind turbulence and resistance. Still, the truck drove well with no obvious issues, so we handed the vehicle back over to George, who paid his bill and drove away.

For the first day everything was fine, but then he called to complain that the truck didn’t have the power and speed it was supposed to have, and that his front brakes seemed rather hot when he stopped and walked around the vehicle, one side more than the other. He asked about the rubber hoses leading to the calipers, but those don’t fail a whole lot unless someone poured oil in for brake fluid or let the calipers hang on those hoses a time or two. Rebuilt calipers were only $15 at the parts store, and so we did the calipers, pads (very thin) and new rotors, because the original ones measured too thin. Another test drive. A cold soak. A second test drive. Everything seemed fine.

The misfire code was handled by replacing the spark plug and wire. The lean codes were handled by repairing a couple of small vacuum leaks.

Once again, George drove the 20 miles to his house, and the next morning he experienced a similar issue with the brakes. It was at this point that I did a mental re-wind to a previous conversation we’d had when he first brought the truck for a fuel economy concern: He had been adding brake fluid for a few weeks but had no idea where the brake fluid was going. As I thought back on that piece of information, I had a sneaking suspicion that proved to be correct when the truck returned. It sat in the service bay for a while before we got to it. We raised the front of the truck and spun the tires. They rotated freely. With the engine started and the brakes applied a few times, and released, it became apparent that the brakes weren’t releasing. Oddly, the passenger side wheel seemed worse than the driver side. But the final analysis revealed that the master cylinder had been leaking brake fluid into the brake booster, which was malfunctioning at times and keeping the brakes applied a little more after each successive stop. When the truck was parked for a while, the brakes would release.

This spark plug showed obvious traces of water and coolant. A dark tip like this one indicates a perpetual misfire condition.

What tripped us up was the fact that, for the first 20 to 25 miles on the highway, there were no apparent problems. But as he was driving to work, the problem would resurface.

Brake fluid doesn’t belong in the booster. While he made two trips back to the shop (to our shame), we didn’t sell him anything he didn’t need with the possible exception of the calipers, but hey, they were only $30 and well worth the money on a vehicle of this age and mileage. In a word, we finally won the fight.

Sebring Rainstorm
The last one is a quickie to tell about and a booger bear to fix. This 2002 Sebring (2.7L) had been losing coolant, and the woman who owns it had been adding clear water until she had almost completely diluted the coolant. We had a low 20s cold snap, and she came in with her cooling system level low and an overheating problem.

The rear of the engine with the cooling system pressurized showed this stream of coolant. Because it had been so cold and the cooling system was nearly pure water, it was easy to misfire on this. Someone who’s more familiar with these engines wouldn’t have stumbled on the diagnosis like we did. Who would think a water pump would cause water to drip from between the engine and the transaxle?

Filling the cooling system, we applied pressure and it looked like a rainstorm coming from both ends of the engine. One of the leaks was coming from between the transaxle and the engine, and because the coolant was almost pure water and the previous night had been a bark buster, I had a lifesize picture in my mind of nasty cracks or shoved out expansion plugs. I had a couple of guys yank the transaxle and the flywheel (it was good for them), and we pressure tested again to see why the coolant was coming from between the engine and the transaxle and found it pouring out of a big hole that opened into the valley.

The water pump was the source of the leak, and we felt kind of buffoonish. The timing chain drives water pump on this engine, and to keep coolant out of the engine oil, the water pump weep hole is routed out the side of the block right by the thermostat housing. It’s difficult to access without removing the A/C compressor. Well, it was clogged, and having anticipated this, Chrysler put an overflow weep hole in the valley under the intake.

This is where the coolant is supposed to leak out if the water pump seal fails, but since it had so completely clogged, the coolant had found somewhere else to go. This problem is, as I discovered, fairly common on 2.7L engines – I inspected another engine we had in the engine shop and found that its weep hole was clogged as well.

The hole at the rear of the engine that lets coolant leave the valley carries it into the bell housing area, behind the flywheel, and down the back of the block so that it makes its exit on the opposite end of the engine. This is one of those mistakes you only make once. Whatever happens, the other end of the engine has to be removed to replace the water pump. Even for a professional, that is a seven-hour job according to the labor guide.

If we were to give up the job of finding and fixing leaks, about 60 percent of our service work would evaporate. Let’s be thankful for leaks and the knowledge to find and fix them, because the motoring public depends on us to put fluids in their place and keep them there.

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