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Friday, August 23, 2013

Dr. Gizmo Column

"Dr. Gizmo"
By Phil Arendt

A Lot Rides On The Timing Belt    
Question 1
Recently, I had my 2004 Hyundai Santa Fe at my local shop for an oil change and general check-up.  It has 66,000 miles and a 4-cylinder engine.  I purchased the vehicle three years ago. 

When the work was done a service man was going over the bill and inspection form when he suggested that I have the timing belt replaced.  I’ve owned four cars prior to this one and have never had anyone suggest such work.  I never had to replace a timing belt on any of them. 

My SUV runs fine.  Since I have owned the vehicle I have taken great care of it.  It’s in great shape.  Is this something that is necessary to do? B.C., email

Answer 1
The timing belt is an important drive belt hidden under a cover on the engine that synchronizes the up and down motion of the pistons with the opening and closing of the valves.  It’s similar in construction to the serpentine belt that you see on the outside of the engine that turns accessories such as the alternator and air conditioning compressor.  If the timing belt breaks due to wear the pistons and valves could collide and cause major engine damage.

According to the factory recommended maintenance schedule for your vehicle the timing belt should be replaced at 60,000 mile intervals.  It’s due for replacement.  It certainly is a lot less expensive to replace the belt than the engine should the belt break.

Exam Of Engine Parts Not Too Intrusive
Question 2
The 2.0-liter engine in my 2007 Volkswagen Passat sounds like a diesel engine.  It has 122,000 miles, an automatic transmission and turbo-charger. 

I went to a repair shop where a technician thought the noise was coming from the timing belt.  He checked it and it’s fine.  He’s not sure what is causing the sound but wants to disassemble the engine to find the source of the noise.
I’ve owned the car since it was new.  I change the oil every 2,500 to 3,000 miles.  The car is in great condition.  Do you have any clue as to what is causing the noise?  W.S., email

Answer 2
Your technician must have an inkling of what is causing the sound and a course of action.  He wants to disassemble the engine.  If you agree to proceed with an internal examination he will inspect parts that might be causing the sound. 

From your description of the noise more than likely it is from the valve system so he won’t be removing the bottom of the engine.  He’ll look for trouble at the top of the engine.  This is not a major operation.  He likely will remove the valve cover so he can examine the cam shafts and other parts that comprise the valve system.  Once he has completed the exam he should know the cause of the sound and suggest a lasting repair.

Coolant Leak Hides From View
Question 3
There is antifreeze leaking from the engine near the air conditioner compressor.  The compressor and lower radiator hose are blocking my view of the leak not to mention the slant of the engine and tight quarters.   The leak is pretty bad as I have to add half a gallon of premix antifreeze every other day which is about 80 miles of travel. 

I have a 2002 Chrysler Sebring with a 2.7-liter motor and nearly 190,000 miles.  Do you have any idea what’s leaking?  S.J., email

Answer 3
Don’t repair it.  Keep topping off the reservoir so the antifreeze manufactures can hire more employees.  Also, the drips of engine coolant on the road will give environmentalists and pet owners something to discuss.

All kidding aside, this problem needs repair to prevent engine damage from the result of overheating.  It is possible the timing cover gasket or radiator hose has sprung a leak.  It is also possible the trouble is caused by a failure of the seal on the water pump shaft.  The water pump has a small weep hole in the case near the shaft and pulley.  Without specialized equipment to examine the water pump it is impossible to see the weep hole without removing parts in the way of view.

When you take the vehicle to a repair shop consider this suggestion.  Your technician will likely find that the water pump needs replacement.

Key Needs Programming
Question 4
My 2001 Mercury Sable won’t start.  A friend who has a lot of Ford knowledge and tools has been helping with this problem.  At first there was a coil that was causing the 3.0-liter engine to misfire.  After installing a new coil we found that the engine computer was the cause of the coil problem.  We installed a new module and now the motor won’t start.  My friend has a scanner that programs engine computers so he programmed the new one but the engine still does not start.  Now he thinks the trouble is in the key.  I only have one.  We had a new key made but this did not start the engine.

Do you have any suggestions?  C.S., email

Answer 4
Sure, buy an old clunker from the early 1980s and you won’t have to worry about anti-theft system problems.  All kidding aside keep your car.  Since your buddy has programmed the engine control module the antitheft system codes do not match.  Now the key code doesn’t match the computer. 

At this point your best bet is to have a new key programmed at a dealership.

To Fix Leak, Remove Transmission
Question 5
I have a 2007 Lexus ES350.  I bought the vehicle in 2010.  I’ve taken good care of it by following the factory service schedule.  The trouble is that there is transmission fluid leaking between the engine and transmission.  What would cause that problem?  M.P., email

Answer 5
You finally asked a question I can’t answer.  I’m just kidding of course.

More than likely the trouble is caused by a leaky seal at the front pump cover or seal at the torque converter.  Regardless of which seal is leaking the transmission has to come out to replace the afflicted seal or replace a flawed hard part such as the torque converter.
Now I have a question for you.  How do you know the leak is from this area and not from somewhere else on the transmission?

Renewed Cylinder Head Proposed To Extend Vehicle Service  
Question 6

The 1.6-liter engine in my 1996 Honda Civic developed a misfire.  My mechanic did a compression test and found low compression in one of the cylinders.  He checked the cylinder using three different tests.  One was electronic and the other two were with a pressure gauge connected to the low cylinder.  One gauge test was wet and one was dry.  I’m not sure what that means but that’s what he told me.
My mechanic is fairly certain that the trouble is in the cylinder head and not in the piston part of the engine.  He says the engine needs a valve job.

My car is in great condition.  There isn’t a bit of rust.  It has 110,000 miles.  It has a standard transmission and a recently installed clutch.  I’ve owned the car since 2001.  It never has let me down.  I follow the service schedule recommended by Honda. 
My mechanic says the engine should run for a long time after the work.  He has worked on it for many years.  A valve job is expensive.  Is it worth fixing?  R.G.P., email

Answer 6
Apparently, you trust your technician.  You have given him many years of business.  I’m sure he does not want to lose your trust and business now.  He likely has made an accurate assessment of the cause of the condition.

The tests he performed have guided him to the conclusion that more than likely a valve is excessively worn.  Also, he has determined that the car will travel for many more years with a renewed cylinder head.
It’s up to you to decide to fix it or not.  You are the only person who can make the decision based upon your budget and the condition of the vehicle.  Certainly, it is less expensive to fix the car than it is to buy a new one.

If you so choose, it’s time to give him authorization to do the work as long as he guarantees his expertise and renewed cylinder head will cure the issue.  If not, it’s time to tow the vehicle to a salvage yard.

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 mailto:drgizmo@hotmail.com.  08/12/2013 ® DR. GZMO © 1989 - Present

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