Dr. Gizmo Column

 "Dr. Gizmo"
By Phil Arendt

Loyal Reader Makes Dr. Giz Smile

Question 1
Hi, Doc Giz!   I enjoy your column a lot.  I even read it before the comics.  I am 84 years old and probably driving my last car, a Saturn.  I find it hard to believe that today's cars are more reliable.  When car computers showed up, we were told the days of "throwing parts" at problems were over.  In spite of trouble code readouts, it seems many mechanics including those at dealers are as befuddled as ever and the art of throwing in parts lives on. 

Also, it's comical how upset folks get over a red light on the dashboard.  The red oil warning light lit up on a 1977 Dodge Colt I owned just as we were about to depart on a holiday trip.  Everything appeared normal, so I put a piece of black tape over the red light.  It was still shinning when I sold the car several years later!  Yes, I know that serious damage can occur from ignoring warning lights, but sometimes common sense gets ignored too.  You seem to have about as much common sense as anyone, so keep on writing, and I'll keep reading!  What do you say?  Your fan R.V., email

Answer 1

R.V. you made my day.  Thanks for being a loyal reader.  I’m sorry that you drive an orphan.  So do I since General Motors and Chrysler closed certain brands.  The good news is you can still have your vehicle serviced and repaired at your local General Motors dealer.

Diagnosing vehicle ailments is more challenging than ever.  Computer malfunction codes provide clues to the cause of trouble.  The clues are a path to repair.  Unfortunately often when one circuit has trouble it affects others and this leads to installing parts that are not needed. 

As for the warning light in your Colt, more than likely the oil pressure sending unit failed.  Thankfully the oil pump did its job and was not the cause of the trouble or your trip could have been delayed along the roadside not far from home.

 

Failed Module Causes Multiple Problems 

Question 2
I have a 2001 BMW 330Ci with turn signals that flash on the outside but the lights on the dash do not blink.  Also, once in a while multiple warnings flash on the dash for the air bags, engine antifreeze coolant and convertible top when nothing is wrong.  The convertible top stopped working but I’m not too concerned about that right now.

I went to a repair shop for these issues.  They said tests did not find any problems but they think the module that controls the lights needs replacement. 

Does this seem right to you?  R.H.L., email

Answer 2

Indeed a body control module controls the turn signals, warning lights and even the convertible top.  If the circuit is in good condition without faults such as loose or corroded connections it is highly likely the module needs replacement.

 

Stripped Gears Overheat Engine
Question 3
The engine in my 2006 Mini Cooper S overheats.  I replaced the thermostat and antifreeze temperature sensor, but the problem persists.  I also went to a repair shop to have them check for a blown headgasket.  They say it is not leaking. 

I love my car but I can’t drive it with this problem.  When I start it in the morning I can only drive a mile before it overheats.  What am I missing?  K.R., email

Answer 3

You are not missing anything.  The cause of the problem just has not been found.  Be this as it may, since the engine overheats so quickly there is either major blockage in the system that prevents coolant from circulating or the water pump is not pumping.  Since the engine is supercharged, it is possible the gears on the supercharger that drive the water pump are stripped. 

Ask your favorite technician to consider this the next time the car is at a repair shop.

 

Spark Timing Is Key To Engine Starts  
Question 4
Recently, my 2002 GMC Envoy with a 4.2-liter engine would not start.  When I cranked the starter the battery was strong and the engine turned but it wouldn’t start.  When this happened I had the truck towed to a shop that has serviced the vehicle for a few years.

A mechanic found a code for a bad crankshaft sensor.  After replacing the part three times the engine still will not.  At first he installed aftermarket parts.  The last sensor was from GMC.  Now he is in the process of trying to determine why replacing the sensor has not resolved the issue.  Testing shows the sensor is fine but the engine is not timed properly.  I’m not sure what that means but I trust what he is doing.

I need my truck.  It’s my baby.  It has 89,000 miles and I have taken excellent care of it since it was new.  Can you help?  L.S.M., email

 

Answer 4

Soon, your baby will be back on the road.  The timing issue could be caused by an electrical issue in the engine control module, jumped timing chain or even a faulty reluctor on the crankshaft.  The issue relates to when the spark plugs fire in relationship to the position of the pistons.  Apparently, the moment the spark plugs fire is off and not within specifications.  Right now your technician likely is trying to determine if this is caused by a mechanical or electrical issue.  Once he rules out one or the other he can focus on the failed system.  Test results will be his guide.

Since you have taken great care of the vehicle more than likely there isn’t an issue such as a jumped timing chain due to excessive wear.  One issue your technician might consider is that sometimes the reluctor on the crankshaft moves.  This is the part the crankshaft sensor utilizes to time ignition signals to fire the spark plugs at the proper time.

 
Recent Purchase Burns Three Quarts Of Oil In 1,000 Miles
Question 5
Recently, I purchased a 2004 Nissan Maxima with 124,000 miles from a private party.  The car looked great and ran fine.  The other day the motor cranked when I turned the key but it would not start.  It was towed to a local repair shop. 

The shop did some tests and found a code for sensors on the cam shaft.  They also found that there was hardly any oil in the engine and upon further inspection they found a lot of sludge in it.  They filled the oil and replaced the sensors.  The engine still would not start.

After unplugging the sensors the engine started but it had little power.  They now think there might be something wrong with the timing chain.  They suggest disassembling the engine to inspect the chain but they fear the engine is shot because of the sludge. 

When I purchased the car the oil level was full.  I drove about 1,000 miles since then and the oil level didn’t register on the dipstick at my shop.  They added three quarts of oil and did not find any leaks.  Do you think the engine is shot?  H.M.O., email

Answer 5

This indeed is a situation with many issues beginning with the purchase but let us focus on the engine.  It consumed three quarts of oil in 1,000 miles.  This indicates excessive wear in the valve system or cylinders or both.  Since there likely is excessive wear in the timing chain and a heavy accumulation of sludge, replacing the engine is the likely outcome.  Probably the best and least expensive option is to install a used engine from a low mileage salvage vehicle. 

Also, in the near future it might be necessary to replace the exhaust system catalytic converters.  They have processed excessive oil from the engine and may soon fail.  Also, the oxygen sensors might fail, too.  Don’t be surprised if they do.

Additionally, since this is an expensive repair you might consider sending the vehicle to another shop for a second opinion.

 

Chirping Noise Develops After Power Steering Repair

Question 6
The power steering quit in my 1999 BMW 528i.  A shop replaced the pump and belt.  After the work the power steering issue was repaired but a month plus later a chirping growling type noise developed.

I returned to the repair shop.  They have determined that the noise is not from the new pump and think that one of the other parts driven by the belt is making the noise.  They say it could be caused by a bad water pump, alternator or tension pulley.  As of yet they have not identified which part causes the sound.

I have owned the vehicle since it was new.  I have taken great care of it.  It has almost 190,000 miles and has not given any trouble all of these years.  Is it possible my shop installed the pump incorrectly or damaged another part during the process that now has caused another part to fail?  C., email

 

Answer 6

Congratulations for driving nearly 200,000 trouble-free miles.  It is unlikely the technician did a poor installation of the power steering pump as it has a mounting assembly that keeps it in alignment with other accessories and the serpentine drive belt.  Certainly, mistakes can happen but it is highly likely that an issue would have surfaced immediately after the installation and not a month or so later. 

Considering the mileage and age of the vehicle it is very likely another part has failed due to normal wear.  From what you describe the noise more than likely is caused by a failed tensioner pulley assembly.  This part places the correct tension on the drive belt that turns the power steering, alternator, water pump and air conditioning compressor.  Replacement should squelch the noise.

Thank you for all the great questions.  Dr. Gizmo can’t wait to answer more.

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.  10/28/2013 ® DR. GIZMO © 1989 - Present