Blowin' Smoke

An Editorial by dieselmann
Volume 8; January 00: Helping your Mechanic

Have you ever picked up your vehicle from repair shop and found the problem you took it in for still exsisted? Or has the shop contacted you to tell you they could not duplicate or verify the concern? How specific were the symptoms you give the service writer? Especially when it comes to intermittent or noise concerns this could this could make the difference between suffering with an on-going problem or have it repaired the first time. I know I have receive repair orders with "customer states noise" or "engine dies" and have been unable to find the problem. What kind of noise? From what area of the vehicle? At what speed or kind of road? Does it die at stops, at cruise/highway speed, low speed; did it do it once, or does it repeat? Was the engine cold or hot? These are all questions that the service writter should ask while filling out the R.O., but many times do not if there are mary people at the counter to be waited on. On the other hand, this is also information which you should volunteer--and ensure it is written down--so the technician can better duplicate and identify you concern.

If you find it frustrating to have to return repeatedly for the same repair, imagine unsuccessfuly trying to duplicate a problem, only to find some crucial information was not reported to you. For example, I have had to diagnose a "noise on turns" on a Mercury Tracer. I was told it comes from the front of the vehicle. Naturally I assumed, correctly, that it was coming from the front wheel area, but I was unable to hear any noise in parking lots, on the street or at highway speeds. After several atempts to duplicate the noise, I had to have the service writter call the customer for more information. Luckily, he was able to get ahold of her--I can't count the number of times we are unable to contact a customer. The most common problem here is getting the customer's home and work phone numbers and not a number where they can be reached. It turned out the car had to be driven very slowly with the wheels turned and slight pressure on the brake pedal. This allowed the front brakes to drag slightly on the rotors which cause the calipers to move back and forth on their anchor sleeves. Under normal brake application the calipers would not move and the noise was not apparent.

Sometimes we receive all the information possible, and still cannot duplicate the customer's problem. Many times I receive an R.O. for a diesel with a hard start when cold concern. Sometimes this is affected by ambient temperature, other by air intrussion into the fuel system after a full nights cool-down from operating temperature. It seems like it would be an easy diagnosis, but not when the truck arrives at noon and needs to be returned by closing. Not only am I unable to verify the costomer's complaint, I can't verify if my repair corrected the problem.

Sometimes it is only a matter of driving style or even how the customer describes their problem. Everbody drive differently. Everyone finds different noises objectionable. And not everyone describes the same noise in the same way. In cases like this, it is important to request that the technician who will be working on your vehicle go for a ride with you so you can show the tech your problem. Keep in mind many shops pay their technicians on a "flat rate" scale. This means they are payed by the job based on a time standard. In most cases, warranty rates and times (what the factory is willing to pay the shop) are less than local standard. If a repair is rated at four hours, the tech gets paid for four hours regardless how long it takes him to complete the job. Not only does not having all the information take money from the technician's pocket, a protracted test drive with you does the same, although if the problem can be duplicated by you it can save both of you time.

As I said above everybody describes things differently. I don't agree with all of Ford's descriptions, and some are the same as others, so here is my list based on theirs.

Boom, droan, moan, hum, howl, whine, whistle:
Noises ranging from sub-sonic (boom) to high pitch. When caused by rotating parts RPM increases pitch. If caused by air flow increased vehicle speed increases pitch. May also be caused by natural vibrations transmitted through stressed mounts or grounded (touching) components.
Chatter, rumble:
A noise caused by a rough rotating part in contact with another.
Chirp, squeak, squeal:
A noise caused by one part contacting a rotating one. Squeal denotes constant contact.
Creak, squeak:
Two parts rubbing together.
Clap, clunk, knock, rattle:
Two parts hitting together.
A noise caused by a shifting or streaching component.
Hop, shudder:
An up and down movement of the entire vehicle.
A slight visable side to side movement of the steering wheel.
A back and forth or speed up/slow down sensation usually associated with braking.
A vibration which can be felt throughout the vehicle accompanied by visible movement of components (seat backs, mirrors, ect.).
A violent side-to-side movement of the entire vehicle.
A movement felt but not necessarily accompanied by detectable movement caused by out of ballance or out of round rotating components.
Driveablity Concerns:
Buck/jerk, trailer hitch:
A momentary loss of power--Buck/jerk at cruise or on accel; trailer hitch on decel. Faster than a surge.
"Cuts out":
A momentary feeling of the engine shuting off.
Hesitation, lag:
A delay in acceleration.
Lack of power:
A feeling of the vehicle not performing as it did or should.
Loss of power:
A feel of reduced power while driving.
One or more cylinders inoperative.
Rough running:
All or some cylinders not operating at full capacity. May be a temporay condition, ie bad fuel.
An unwanted shut down of the engine, either sudden or gradual.
Surge, rolling idle:
A fluctuation of engine RPM.
Adding "ing" to any of the above denotes constant or repetative.

At your next visit to a repair shop, please try to be as exacting as you can when describing you problem. Try to take note of what conditions exsist at the time of occurance. Hopefully this, and possibly the descriptions I provided above, will help to resolve your concern.

Charles David Ledger; dieselmann1999

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