Human error compounds vehicle repairs

July 28, 2014
A professional repair is one that is done completely. Doing a repair completely means completely solving the problem, completely resolving the customer’s concern and completely preventing it from ever happening again, if possible. 

There seems to be a prevailing attitude among a growing number of people employed in the automotive repair industry who must believe all automotive engineers are idiots. At least, that’s the conclusion I’ve come to when I see how some (I refrain from referring to them as “techs”) have attempted to resolve their customers’ complaints. What they do can’t be called fixing cars.  Some of the repairs I’ve witnessed have been attempted in the most interesting ways. I’ve been both entertained and disgusted by how some have re-engineered system designs, and I ponder the thought processes they must have gone through to develop their solutions.

I’ve also been embarrassed by the blemish such non-professional practices place on the industry as a whole. I wonder if the vehicle owner was charged for such a horribly botched job (rhetorically stated, of course). I wonder how much time and materials, how much blood, sweat and tears, how much pain must have been suffered while doing the so-called “repair”.  Let’s define all that stuff by what it really is: waste. Have you seen examples of this too?

The current pattern taken on the cooling fan motor offered a potential cause for the intermittent overheat.

A Professional Approach
A professional repair is one that is done completely. Doing a repair completely means completely solving the problem, completely resolving the customer’s concern and completely preventing it from ever happening again, if possible. It’s the goal I strive for. I’ve found being a professional automotive technician to be rewarding in many ways including financially as well as emotionally, and don’t imagine a “hack” feels anything like rewarded.

Those who know me have most likely heard me say, “I’m one of the laziest people on Earth. I don’t want to work any harder than I absolutely have to.” I am proud of my ability to imagine ways to perform repairs faster, better or longer lasting, but in the end, I perform the repairs as they should be done and strive to not create other problems in the process. Of course, I use creative methods to diagnose the problems. After all, I want to get the most information in the shortest period of time possible.  But I don’t even consider re-engineering a system, bypassing functionality or safety features, in order to affect a fix. That’s not the kind of lazy.

When called to diagnose a vehicle, I start by playing 20 Questions, the same way you should ask your customers when they present a diagnostic situation to you. I use the answers I’m given to narrow down what might cause the complaint and eliminate what I don’t need to test. I mean why look at the whole car if only a small part of it’s affected? That’s my kind of lazy.

Is there a way I can be lazy when I’m called to a shop that is now the third one to attempt to address the customer’s concern of “intermittent overheating” or will I have to actually (sorry for using a four-letter word here) work? What questions might you ask of the technicians who have run out of ideas how to resolve that complaint on a simple, non-exotic vehicle?

A Lazy Diagnosis
Let me share an example of a case I was called in to assist with to further differentiate one form of laziness from another. The vehicle owner complained her 1988 Nissan Sentra would overheat intermittently while in bank or fast food lines or stopped at traffic lights. Steam from under the hood and coolant would boil onto the ground, all classic symptoms. The electric fans worked every time the air conditioning was turned on, and thermostatically when the air conditioning was off.  My first question was directed to the shop owner, asking what repair attempts already had been made. He told me that a couple of thermostats, water pumps and radiators had been installed during previous repair attempts. 

You never know what you’re going to be called in to help with when you run a mobile diagnostic business.

Let’s pause here and consider what information I’ve received so far. I can comprehend how a thermostat can act up every now and then, and a water pump impeller spinning on its shaft can pump fluid at times and not at other times. Both of these situations I’ve experienced personally.  But, there was at least one shop/tech that believed a radiator would cause an intermittent problem, one that only occurred at idle.

I just have a hard time condemning a radiator for an intermittent problem. It scares me when I think of the reasoning (or lack thereof) used to condemn the radiator in this instance (twice at that). Do you agree with me here? If there were debris blocking the flow periodically, then a flush would remove it (and it wouldn’t be the fault of the radiator). If debris were present in the coolant, it would overheat under a variety of driving conditions. In any case, the odds that any of these items are faulty — yet produce the exact same symptoms as the vehicle owner originally described — are astronomical.

The current shop working on the vehicle thought possibly there was a blown head gasket or a cracked cylinder head. I’ve experienced only one vehicle that had a cracked cylinder head and exhibited symptoms that were intermittent in nature. That’s one in possibly thousands of vehicles I’ve worked on, so it’s not impossible though improbable. Can you think of any super-easy tests to confirm or to disprove the possibility?

Considering everything else had been replaced without success, I thought a test of the cooling fan motor condition was in order.

I used a cooling system pressure tester on the one of these I saw. It passed the first two or three times the car was in for the same complaint. The last time, I checked it over and over throughout the day then I got distracted, forgot that I left the cooling system pressure tester on the car and went home for the night. The next morning I saw all the pressure had gone down but there were no external signs of leakage. I checked the oil level and saw it slightly over the full mark but the oil filler cap showed no condensation or signs of coolant in the oil. I pulled all the spark plugs and noticed one had green coolant on the tip. The “a-ha” moment! Once torn down, a crack could be seen on the port side of the exhaust valve seat on one cylinder but it was only leaking at certain temperatures.

Fast-forward a few decades to the Nissan. Because this was an overheating situation and not just a “coolant loss” complaint, I didn’t need to leave any testers attached overnight. To quickly eliminate the same possibility of an intermittent combustion chamber coolant leak, I chose a 5-gas analyzer instead of a coolant pressure tester. I was confident that everyone before me had pressure tested the system already. The 5-gas analyzer showed no hydrocarbons (HC) in the coolant reservoir. 

Having quickly disproved the shop’s suspicions of a combustion chamber coolant leak, I continued to prod for more information. “Is the condition repeatable?” “Is there a geographical region where the problem shows up?” “Must the ambient temperature be above a certain point?” “Does it do it with a fox?” (Not really, but this interrogation method reminds me of Dr. Seuss’s “Green Eggs and Ham.”)

The problem was not repeatable, so I fell back on the old reliable culprit that I usually find to blame for most intermittent problems – the bad electrical ground. I tested each and every ground on the car, whether it had anything to do with the Engine Control Module (ECM), cooling fans or not, without any success. All had less than 50 mV drop to the battery negative terminal.  Considering everything I knew to this point, I felt sure it must be an electrical malfunction that caused the problem to be present intermittently. It might help you to follow my thinking if you consider this is an OBDI car. The ECM only has blink codes, and it passed every one of the five diagnostic modes. What would you want to do next? 

I now make a practice of comparing the VIN of the ECM to the actual vehicle VIN.

I researched all kinds of service information as well as the other technical resources available to me at the time but found no silver bullet that might help me get to the solution. I examined the wiring diagram intensely and decided to current ramp the fan circuits. I was able to immediately identify a fault in the cooling fan motor windings but had to take a few minutes examining the waveform before I understood why this could cause the customer’s complaint. 

The Answer, My Friend
The single current pattern revealed a shorted armature segment in the fan motor. I figured if the shorted armature commutator stopped on one of the brushes, the fan might not start the next time it was needed. It might occasionally create a small magnetic field, depending where the armature came to rest, that might cause rotation. But if it was unable to and there was no vehicle movement, the engine could overheat. Once the vehicle began moving again, air flow through the radiator not only might keep the engine from overheating, but the air flowing through the radiator and fan might rotate it slightly allowing it to start next time.

I had less than one hour invested. It’s sometimes difficult for us to imagine things that might cause problems if we can’t conceive things outside our own experiences. I think this is why the suggestion for a head gasket replacement was made. It also might explain why identical conclusions were made about the parts previously installed. After all, because the fan always worked when expected, why would we suspect it? And I might tend to agree if the problem hadn’t been specifically described as “intermittent.” If someone who earns a living in the same business I do could consider a radiator as a potential source of an intermittent problem, why wouldn’t you consider the fan motor as a more likely candidate?

In the Kia’s case, it helped me uncover the first problem that required correction, the wrong ECM for the car.

Lazy Has a Process
Here’s another example I’d like to share with you. I was called in to diagnose a “Cranks OK, won’t start” complaint on a 2004 Kia Sedona V-6 that was in a used car lot. I know, I know. Lots of flags went up right away when I got this call and I should have heeded the warnings. Used cars typically have little to no history, most times have been “hacked” and (magically) must be fixed without the current owner spending much money. Unfortunately, this one was no exception. It was bought at an auction, was heard and seen running, was diagnosed with blown head gaskets after it overheated (sound familiar?) and has not run since. 

Someone deemed it necessary to replace the head gaskets and during that process damaged electrical connectors, neglected to install all of the bolts (including the ECM ground eyelet bolt), and generally had done a slipshod job. This individual got fired and didn’t understand why. Now the job was passed on to the replacement. Working within the limitations of his own inexperience and those imposed by the used car lot owner (no tooling, no training, no money), he quickly exhausted all his capabilities and convinced the owner that I was the man that can fix this car. I felt challenged and wanted to live up to my reputation (ignoring my instincts). Once again I began by playing 20 Questions with the tech and the owner of the lot. 

Upon arrival, I gathered as much information about the vehicle as I deemed necessary to perform an initial evaluation then headed to the car. I brought with me the factory scanner, a Power Probe and my laptop only to find the vehicle had a dead battery, a partially disassembled interior and almost the entire engine electrically and mechanically intact. Oh, and it was outside and about to start raining. I silently reviewed all the questions I’d asked and didn’t remember asking the important ones that I obviously should have before heading their way. I made a mental note-to-self for the future.

Another drawback to mobile diagnostics work: finding and correcting the little things, like disconnected and damaged wiring.

After reassembling as much as we could see that was not right in the engine compartment and charging the battery, I began my analysis by scanning the ECM. “No communication with selected module” was the response. Initially, I figured a blown fuse or another ground was off, but neither was the case. It was then when I understood why the interior was partially disassembled. I wanted to check power supplies and grounds at the ECM and found one with yellow tire crayon markings scribbled on it. Stuff like this is what I call the “Paul Harvey time,” or the time when you get the rest of the story. 

“Oh that?” the tech told me.“We tried another ECM from the junkyard, It did the same thing, so we left it in there.” I identified this donor module and found it was from some other 2005 Korean-made vehicle, then entered the vehicle information as a “2005” to read the ECM. I researched enough to learn it could never work in this 2004. You already guessed it, didn’t you?  The original was returned and no longer available, so I ordered a rebuilt unit that was appropriate for this vehicle.

I won’t bore you by going into further detail about each painful step of the diagnostic process; after all I’m sure most of you have experienced similar situations in your careers. I ultimately was able to determine the cause of the no-start. Once I confirmed the ECM was doing its job and all my basics were correct, I visually inspected the four camshafts that were reinstalled after the head gaskets were replaced. 

For future reference, cams with an “I” stamped on their ends are for the Intake valves and the cams stamped with an “E” are for the Exhaust valves. Once the camshafts were oriented in their correct positions on each head and the timing components’ correct installations confirmed, it amazed the owner and technician how little cranking was required for this engine to come to life.   I did what I was called in to do, that is, get it running. I’m not sure if there still was an overheating condition afterwards or not and really didn’t care.

In each of these instances, a lot more work was done than was actually necessary. Work that was caused by what I call “compounded human errors.” Had the correct diagnosis been performed initially, a huge amount of waste would have been avoided. Wasted energy, wasted time and wasted money. I just shake my head sometimes. Compounded human errors also make me work harder than I should, and I’m too lazy for stuff like that. 

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