Reporter Richard Truett, in his "Hands On" column in the December issue of Fixed Ops Journal, raised the question: What happens when a self-pay customer knows more than a dealership service adviser about how to repair his or her vehicle? We invited your responses. Dean Merrifield of Medina, Ohio, a former engineer with Ford Motor Co., shares his experience:
I'm a retired automotive engineer with 30 years at a major automaker, a chunk of that time in product development. I'm ASE-certified and a do-it-yourselfer with six cars, ranging from a 1929 Ford Model A pickup to a 2014 Ford Mustang Shelby GT500. I dread dealing with dealership service departments.
I own a 2016 luxury car and have it serviced at a dealership, but only because it's under warranty. I change the oil and rotate the tires to reduce the potential for dealership mishaps.
The temperature gauge was fluctuating below the normal operating temperature after the car warmed up. I bought the original equipment shop manuals (eight 200-page volumes) and read the sections on cooling systems. I connected a diagnostic tool to the OBD-II port and monitored coolant temperature data.
There were several potential causes:
- Instrument cluster malfunction.
- Engine coolant temperature sensor malfunction.
- An intermittent ground issue in the cooling system circuit.
- Thermostat malfunction.
- Cooling fan malfunction.
To make matters worse, the problem appeared to be intermittent. I spent about an hour driving the car on different occasions, comparing OBD-II coolant data to the temperature gauge cluster reading. The coolant level was fine.
The OBD-II data and gauge fluctuation matched and the temperature changes were smooth, not erratic. I ruled out the cluster malfunction and ground issue.
The car never overheated. That ruled out the cooling fan.
The gauge did not fluctuate at idle or with the engine under load, as during freeway driving. That ruled out the temperature sensor.
I noticed gauge fluctuation only at part throttle, with vehicle speeds up to 45 mph. That led me to believe the thermostat was partially open. My hypotheses was that under light engine load, coolant was constantly flowing through the radiator, causing enough heat rejection to prevent a normal operating temperature from being attained.
Armed with this information, I went to the dealership, explained the temperature gauge fluctuation and allowed the service department to diagnose it. The response: "We can't repeat the condition. Operation is normal."
I shared a video of the coolant gauge fluctuation with the service adviser. The response was the same: "That's normal operation."
I pointed out that none of the six loaner vehicles of the same brand that I've driven when my car was being serviced exhibited this condition. I asked: "How is this normal?" The response: "Tech says it's normal."
The service writer should have immediately gone to the service manager for counsel on how to handle this issue. Instead, I searched out the manager and shared the video. I explained the construction of the thermostat, its relationship to the overall cooling system and my hypothesis.
His, response: "Well, that doesn't look normal. We'll have a field service engineer look at it."
Ultimately, the dealership's lead service technician looked at the video, and gave direction to replace the thermostat. Problem solved.
I feel fortunate that the car was repaired. I had the impression that without intervention by the service manager, some of the dealership's customers go away frustrated.
In other industries, some customers are identified as "super users." These customers have earned the trust of the service provider, and interaction is handled further up the chain.
I would have been satisfied just to talk directly to the technician. I think he and I would have agreed.
