"Dr. Gizmo"
By Phil Arendt
Mystery Oil Might Cure
Trouble
Question 1I have a 1998 Honda Accord with a 4-cylinder engine. I was out of the country for nearly a year. The car was parked the entire time. It was running fine when I parked it. When I returned it cranked but would not start. I had it towed to a shop where they did many tests. They determined that the engine has very low compression. They said it’s possible that the piston rings are stuck. They might need to replace the engine.
My car is in excellent
condition despite having 150,000 miles.
I have owned it since it was new.
I have always changed the oil every 3,000 miles. I also follow the schedule in my maintenance
book. I have owned other Hondas and
never had this problem. Do you think my
shop’s diagnosis is correct? R.H., email
Answer 1
Piston rings can stick but
it may not be necessary to replace or overhaul the engine. Ask your shop to consider adding mystery oil
to the cylinders through the spark plug holes.
After the oil soaks into the rings the compression might come back to
normal and the rings will no longer be stuck.
This should be followed by a thorough chemical flush. This might do the trick and return the engine
to normal operation.
A/C Dye Invisible To The
Naked Eye
Question 2I've owned a 2007 Lexus ES350 since it was new. It now has 80,000 miles. Recently, I had a local mechanic add Freon to the air conditioning unit since it was not cooling properly.
It worked fine for three to
four weeks and then began to malfunction again.
I returned to the mechanic
who again added a small amount of Freon as well as some stop leak and dye for
tracing a leak. Thereafter, I checked
the condensation on the ground and did not see any trace of the dye.
I'm about to contact him
again but I'm concerned we may not be approaching the problem correctly. I'd appreciate your comments. Could this be something more serious? B.D., Woodbury, Minn.
Answer 2
Depending upon which dye
your technician used it might not be visible to the naked eye. A special
light and glasses likely are needed to detect the dye at the area of a leak.
Additionally, you don’t want
to see dye in the dripping condensation. If it is in the water it means
the evaporator core is leaking refrigerant. That’s an expensive repair
that requires disassembly of the dash.
It appears your technician is
on the right track.
Vibration Is Normal
Question 3Two months ago, I purchased a 2002 Audi A6 Quatro with a 3.0-engine and automatic transmission. It has 155,000 miles on it. The private party that sold the car gave me copies of all the service records. It’s in great shape and runs great.
A week ago an engine mount
broke. My shop replaced the broken mount
and suggested replacing remaining mounts due to the age and mileage. They replaced all of the mounts at the same
time. Since the work I feel vibrations
from the engine. My shop says it’s
normal to feel some vibration but they suggested replacing the mounts again but
this time they want to install mounts from a local dealership. The parts are more expensive and I will need
to pay the difference.
Will installing the dealer
parts eliminate the vibration? K.L.,
email
Answer 3
It is normal to feel some
vibration from the engine. The dealer
parts might reduce it some but will not completely eliminate all
vibration. While vibrations might be
annoying it is not a condition that is consistent with a mechanical problem in
the engine.
Computers Fail To
Communicate
Question 4I recently purchased a 2001 Ford Escape with 16,112 miles. It’s like new. I was in an estate sale. So far I’ve had the brakes replaced because the rotors were pitted from rust. The shop that did the brakes also found dry rotted tires so I’m replacing all four even though they have plenty of tread. Also my shop replaced all the filters, flushed the cooling system and changed the oil. They suggested new spark plugs but I haven’t had any issues with the way it runs.
One issue that came up while
they checked it over was that their diagnostic scanner does not communicate
with computer modules. They tried two different
scanners but neither one could communicate.
They say that this might be caused by rusty wires and it might take a
while to determine the cause. I haven’t
given them the okay to do any work.
The car starts and runs
fine. No warning lights are on. If the computer is malfunctioning wouldn’t
there be a warning light on in the dash?
Wouldn’t it have problems like starting problems? G.J., email
Answer 4
Logic would conclude that a
warning light such as the check engine light would illuminate on the instrument
cluster. Unfortunately, logic sometimes
flies out the window. Sometimes
electrical issues block communication between diagnostic tools and computer
modules. Since your vehicle likely was
parked a majority of the time since manufacture, it is likely corrosion blocks
communication at a ground connection or plug.
It’s also feasible a hungry rodent has created an issue by chewing on
wiring.
The first place to look for
trouble is the circuit to the diagnostic link plug under the dash where a
technician plugs in a diagnostic scan tool.
Since the car starts and runs fine it appears modules are doing their
jobs controlling engine emissions and accessories, it is likely the cause of
the concern is in the circuit that links diagnostic tools to the
computers. It should not take very long
for an experienced technician to determine the cause.
Good luck with your new
ride. It should provide many years of
service once this issue is repaired.
Scan Tool Fails During
Computer Programming
Question 5I have a 2007 Chrysler Pacifica with a 4.0-liter engine that stalled without any warning. When this happened I attempted to start, but all it did was crank when I turned the key. It didn’t even try to start.
I had the vehicle towed to a
good shop that has been servicing our cars for several years. They determined that the engine module failed
and installed a new one. They were
attempting to program the new module but it stopped at a certain point during
programming and will not go any further even after several attempts. Their top mechanic has tried three different
tools to program the module without success.
At this point they are stuck. They suggest towing the vehicle to a
dealership
Can you help? T.D., email
Answer 5
One alternative is to send
the vehicle to a dealership. Sometimes
aftermarket scan tools have trouble programming computer modules. In such a predicament a trip to a dealership
with a manufacture scan tool completes the job.
Sometimes local independent shops have a good relationship with a dealer
and the dealer will lend the scan tool to them to complete the repair. Another option that some shops utilize is contracting
the help of a service that comes to the shop with a factory scan tool to
complete programming.
Ask your shop manager to
consider these options. Perhaps the
vehicle does not need an additional tow.
Question 6
I have a 1998 GMC Sonoma with a 4.3-liter engine. It has 67,000 miles and is in great condition. I’ve owned it since it was new. I’ve taken great care of it by following the factory severe service maintenance schedule. I also change the oil and filter every 3,000 miles. The trouble is that right after an oil change the engine runs rough. I returned to the shop that did the work but they looked over the engine and did not find any issues with the spark plugs or anything else.
I took the truck to another
shop. They showed me a broken mount on
the transmission. They replaced it but
the engine still shakes. This shop does
not think anything is wrong in the engine or transmission.
The truck runs fine. It just does not idle smooth. No warning lights are on. Do you have any suggestions? G.R., email
The fact that the engine developed a rough idle immediately after an oil change is suspicious. Consider checking the oil level. Perhaps it is overfilled. If this is the trouble the crankshaft is slapping against the oil. This causes it to run rough. If this is the cause of the issue, draining the oil to the proper level should cure the trouble.
Phil Arendt is a columnist,
consultant and A.S.E.-Certified Master Technician. Readers may send questions to Dr. Gizmo at
P.O. Box 548, Cary, IL. 60013 or e-mail address drgizmo@hotmail.com. 07/28/2014 ® DR. GIZMO © 1989 - Present
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