Curious About Rustproofing
Question 1I own a 2000 Dodge Grand Caravan that I've had since new. It has developed extensive rust in the rocker panels and along the lower edges of the doors. Around the time I bought it, there was an automotive journalist that wrote a weekly column in a major Chicago area newspaper. He wrote several times in his columns that buying aftermarket rustproofing for new cars was a waste of money; new cars didn't need it. Well, in my case, that was not true.
At some point
soon, I will have to replace my van. What are your recommendations
regarding aftermarket rustproofing for today's new cars? D.P., Spring Grove, ILL
Answer 1
Rustproofing does not prevent all rust. It all depends upon the construction of the
part.
Let’s consider your vehicle.
The rust around the lower edges of the doors more than likely formed at
a crimp or pinch seam where the outer panel connects to the inner panel. This is also an issue for the rocker panels
beneath the doors. Rustproofing will
not prevent moisture from seeping into these areas unless the vehicle is sealed
on the inside and outside. I’ve seen a
few cars in my many years in this business that did have undercoating applied to
inner and outer panels but in my opinion the vehicles did not have the appeal
that most people look for in a vehicle.
Comparing vehicles of today to vehicles manufactured in 2000 more
anti-corrosive materials are in today’s vehicles that will resist rust but the
weaknesses of the pinch and crimp seams still exist although manufactures apply
sealants in these areas to help prevent moisture and the formation of
corrosion.
All vehicles suffer from corrosion somewhere whether it’s in the
suspension, sub-frame assembly, fasteners and body. Rustproofing will not prevent it. Surface chips to the body expose metals to
moisture and chemicals that form rust.
Once it starts it’s nearly impossible to stop and let’s face it the
average motorist does not get down under a vehicle to check for chips in the
rocker panels to repair problem areas.
Manufactures have made great strides in the use of sealers,
adhesives, entire body anti-corrosive coatings and metals used in the
construction of vehicles to help prevent the formation of corrosion. Despite this a vehicle is not rust
proof.
In the future when you purchase a new vehicle, applying
rustproofing can void the manufacture corrosion warranty. Check the manufacture warranty policy before
modifying the original design of any vehicle as a modification such as rustproofing
might cause corrosion.
Shop Fails To
Find Cause Of Trouble
Question 2I own a 2004 Cadillac SRX that developed a misfire. My repair shop has replaced the spark plugs, tested the cylinder compression, swapped ignition coils and fuel injectors, checked for vacuum leaks and more but the misfire continues. The misfire is affecting the cylinders in one side of the engine.
My car has
133,000 miles. The check engine light
turns on. Sometimes it flashes and
sometimes it shines steadily. Tests are
inconclusive. What do suggest I do
next? B.T.P., email
Answer 2
Roll the car
into the first McHenry County gravel pit you can find. There are plenty of them around.
All kidding
aside, return to your shop. Better yet,
it’s time to have another shop take a crack at diagnosing the trouble. It appears the present shop has exhausted
their expertise and resources. A fresh
look at the problem at another shop might just find the cause.
If you should
decide to return to the present shop ask the manager to consider thorough
testing of the oxygen sensors on the afflicted side of the engine. It’s possible a sensor is not responding as
designed. This might result in
information to the engine control module that is causing an excessively lean or
rich fuel mixture. This type of
condition can cause cylinders to misfire.
If so, replacing an afflicted sensor might be a lasting cure.
Timing Chain
Causes Rattle Sound
Question 3There is a rattling sound coming from the front of the 6-cylinder engine in my 2008 Kia Sorento. It has 77,000 miles. I bought it two years ago when it had 51,000 miles. Since I bought it I have taken great care of it with oil changes every 3,000 miles.
I went to a
repair shop where they at first thought the noise was coming from the drive
belt. They replaced it but the noise
remained. Now they think the timing
chain is making the noise but they say that they have never seen a Kia Sorento
need a chain before so they think there might be other causes for the
noise.
Is it common for
a timing chain to need replacement at this mileage? B.L., email
Answer 3
It’s unusual for
a timing chain to need replacement at the present mileage. Typically this needs replacement maybe never during
ownership but it’s something to think about replacing beyond 100,000
miles. Be this as it may it is possible
it needs replacement now. It’s also
possible the tensioner assemblies that keep the chain tight are worn causing
the chain to rattle. Another cause might
be low oil pressure or restricted oil flow to the tensioner assemblies.
A technician
won’t know for sure what causes the trouble until he uncovers the chain
assembly for examination.
Repeated Failure
of Fuel Pumps
Question 4I have a 1987 Ford F-250 pickup with a 7.5-liter engine and 30,000 miles. This is the last truck with a carbureted engine and it’s in like new condition. The trouble is that the fuel pumps burned out. I replaced both of them and the fuel switching valve. I sent both fuel tanks to a shop to have them cleaned. I ended up replacing one tank. After the work, 150 miles later the pumps burned out again. This time I installed new pumps from a dealership but they burned out 99 miles later.
I’m about to
pull my hair out over this problem. What
should I do next? B.L., email
Answer 4
Buy a wig and sell
the truck. I’m just kidding. With only 30,000 miles the truck isn’t broken
in.
It’s time to
check for current draw. It may be too
high due to poor ground connections.
It’s also possible there is a restriction causing too much back
pressure. Check the lines for
restrictions, fuel pressure regulator and fuel return valve on the carburetor. Repair all depends upon your findings.
Vacation
Extended Due To Car Trouble
Question 5The engine stalled while driving my 1999 Nissan Maxima on the highway while on vacation. I’m still on vacation now without my car. I attempted to start it several times and the battery went dead. I did not realize I had run out of gas.
I had the car
towed to a repair shop where they charged the battery and poured five gallons
of gas in the tank. After this the
engine cranked but would not start. They
said the security system kicked in and won’t allow the engine to start. They said they need to tow the car to a
dealership to have this problem repaired.
Does this seem
right to you? P.P., email
Answer 5
Wow, trouble
occurs in threes. Indeed it is possible
the security system prevents starting.
Since the repair
shop suggests towing the vehicle to a dealership it’s obvious they are not
equipped to repair the trouble. It’s
time to tow it. It’s possible the key
needs reprogramming. If so, the security
system will decipher the code after programming and the engine will start.
Huge Temperature
Swing In Air Conditioner
Question 6The air conditioner in my 1995 Nissan Maxima is not cooling normally. My repair shop has replaced the compressor, expander valve and receiver valve. Despite this it isn’t cooling properly.
When I’m stopped
at a light or driving in heavy traffic with the controls set to the coldest
setting the air temperature at the vents is around 70 degrees. When driving the temperature often drops down
to around 40 degrees at the vents.
My shop says
everything is working correctly. They
don’t know why the air conditioner acts this way. Do you know what’s up? R.C., email
Answer 6
The fact that
the temperature goes up at a stop or in heavy traffic is not unusual but the
dramatic swing in temperature is not normal.
Although your shop assured you that everything is operating normally
there appears to be an issue with air flow through the engine cooling radiator
and air conditioning condenser. There
might be debris blocking air flow. The
shrouds that funnel air through these parts might be broken or missing. The cooling fans may not be functioning as
designed.
The next time
you visit your shop ask them to consider these suggestions. Perhaps they may find something unusual such
as a mouse nest is blocking air flow.
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. 08/26/2013 ® DR. GIZMO © 1989 - Present
No comments:
Post a Comment