Western-Star

Q I am retired and looking to purchase a safe, reliable, economical used car, but not a small car. Do you have any suggestions for me? — G.W., e-mail

A Narrow your search to vehicles about three years old with mileage under 40,000 miles. Since you are not interested in small cars consider midsize and full-size vehicles. Many midsize vehicles with four cylinder engines and some with six cylinder engines achieve decent around town fuel economy in the 17 to 25 mpg range. It's a little more difficult to find a full-size car that achieves midsize car fuel economy, but if you're looking for a roomy interior, go for a full-size vehicle.

Consider having any used vehicle thoroughly inspected by an experienced technician before you make a commitment to purchase. The inspection should be performed by an independent party, such as your favorite local mechanic, even if the vehicle has gone through a certified used vehicle program that many car manufacturers and dealers advertise. This inspection should take about an hour and be comprehensive.

Testing Dr. Gizmo

Q In a recent column, you commented that the air conditioning system could freeze weak antifreeze. I have some knowledge of autos, and the only thing I think that would have sufficient contact between the systems would be the condenser, which is the "hot" side of the A/C system. How is freezing possible?

J.H., West St. Paul, Minn.

A You must be referring to G.G., who is taking his Chevy on a trip to Florida. I mentioned that he should make sure the coolant protects to minus 40 degrees even though he's headed south. The part that could freeze is the heater core. It's in the duct adjacent to the air conditioning evaporator core where the temperature can be below freezing. If the heater core freezes, coolant does not circulate as it should. This could lead to an overheated engine.

Also, the heater core might be damaged. Frozen coolant expands. When it does, it may crack the heater core. This would result in coolant leaking onto the front passenger floor, creating a sloppy mess — not to mention a hefty repair bill.

Another reason to have a sufficient coolant mix is to prevent overheating. A mixture of water and antifreeze does a better job of cooling the engine than good old water. Many late-model engines normally run at temperatures between 220 to 230 degrees — well above the standard 212 degree boiling point of water. It's impossible to operate at these temperatures without a proper coolant mixture and properly pressurized cooling system.

Concern over lack of fuel pressure

Q I decided to replace the fuel filter in my 2003 Chevrolet Impala with a 3.8-liter engine. When I depressurized the fuel system at the valve on the fuel rail, there wasn't any pressure. After this, I replaced the fuel filter without any problems.

Should there have been pressure at the fuel rail pressure bleed valve or does the pressure bleed off after a while? B.N., e-mail

A The fuel pressure may or may not bleed off after a while. To be safe the standard practice is to bleed any pressure from the system whether the car has been shut off for an extended period or not. Also, another safety procedure is to disconnect the negative battery cable from the battery to make sure that the fuel pump doesn't cycle as a result of someone accidentally turning on the ignition key.

When servicing the fuel system, follow all car maker safety procedures listed in the repair manual. Not doing so could lead to fire and death.

Trans repair not too unusual

Q I have a two year old car. It now has 16,000 miles on it. The valve body in the transmission needed a lot of work. Since the repair the transmission works fine.

Isn't this unusual for a car of this age? Did I buy a Lemon? What will happen in the future? A.A., e-mail

A It is a little unusual for such a fault but not uncommon. The transmission is a very complex piece of equipment. All it takes is a malfunction of one small part to cause big problems and even complete failure. The valve body is a combination of electric solenoids, valves, check balls and many feet of passages that direct hydraulic pressure to clutches in the transmission. Apparently there was a defect in the valve body. It's likely that a technician replaced the unit and did not repair it. It's likely that the new part will last for many years.

Also, depending upon the lemon law in your state, it's likely your car does not meet the qualifications to be labeled a Lemon. Seek the advice of an attorney. You also can search your state's web site to learn more about the Lemon Law.

Truck moans and groans in the morning

Q In the morning upon the initial drive of the day intermittently I hear a grinding and groaning sound in my 1998 Chevrolet S-10 pickup that pedestrians can hear. I can stop the sound by pulling off the road. When I'm stopped I hear a clunk sound. After I hear the "clunk" the truck drives normally. My truck has a manual transmission and four-wheel-drive. What is breaking down? H.P., St. Paul, Minn.

A Your truck sounds like me when I get moving in the morning. Unlike my worn bones the problem with your truck likely is the result of something in the driveline that is need of lubrication. Something is binding such as the splines on the drive shaft slip joint. Maybe a four-wheel-drive hub or a shaft in the four-wheel-drive is binding.

Your best chance for a technician to find the cause is for you to leave the vehicle with him overnight so he can drive it first thing in the morning as you do. Once he hears the sound he will know where to look for the cause of the noise.

Also, if you take the truck to a shop for a lubrication of the driveline the noise may be cured after the service.

Fix for hot engine

Q The 2.4 liter engine in my 1991 Dodge Ram 50 pickup truck runs hot. The engine is a used engine with 94,000 miles on it. I replaced the thermostat, radiator and fan clutch. Despite this work the engine continues to run hot and it loses coolant. What's up Doc? J.S., Oxford, Wis.

A You have a hot mama. All kidding aside the first items to check are the temperature gauge and radiator cap.

Perhaps the coolant temperature sensor on the engine has a malfunction. Maybe the temperature gauge on the dash is faulty. If either has a fault the engine may appear to be overheating when it is not. If so replacement of the faulty unit is the cure.

It's also possible that the pressure cap on the radiator is not doing a proper job. If the cap isn't performing as designed the pressure in the cooling system may be low. As a result the engine coolant is likely to boil. If this is the case, a new cap will end your woes.

Perhaps, the used engine has blockage somewhere in the water jacket. A chemical flush might clear the passages to return proper coolant flow. This might cool down your truck.

Lastly, it's possible the water pump impeller is suffering from excessive wear. This reduces coolant flow through the system and raises the engine temperature. If this is the case a new pump is the cure for this condition.

Check history before purchase

Q I'm considering the purchase of a new 2007 or 2008 Chrysler minivan, but I don't understand a few things. J.D. Powers reports that the minivan is great, but Consumer Reports gives them their lowest reliability rating. Also, I see thousands of them on the road. What have I missed? G.B., e-mail

A You haven't missed anything. The Chrysler minivan is a popular vehicle. It serves a wide variety of uses for all types of lifestyles from commercial use to hauling a soccer team. In one day it can make a morning run for garden mulch and in the evening it can travel downtown for a fancy night on the town. This is one reason you see so many on the road.

J.D. Powers provides an initial quality rating based on new customer impressions. Consumer Reports surveys their base long after the purchase. As a result you encounter two different survey results. Owners love their new vehicles and more than likely have not had any trouble with them. Motorists who have owned a vehicle for a couple of years are more likely to have had some kind of repair performed so the vehicle gets a poor rating.

No one can predict what your experience will be with a new minivan so base your purchase decision on the vehicle's history and your needs.

Oil filter has limitations

Q In a recent column you addressed the importance of oil changes and how dirt and grit wear an engine. You didn't mention the oil filter. Doesn't the oil suspend dirt and grit which is carried to the oil filter? Why aren't there more additives in oil? P.B., Osceola, Wis.

A You bet that oil suspends grit and grime. One of the most important jobs of oil is to clean the inside of the engine. It also carries the contamination to the oil filter. The oil filter does indeed remove most of the dirt and grime. Eventually the oil filter becomes full similar to a garbage becomes full. Once this occurs, grit and grime is not filtered and is circulated back into the engine. Also, the filter doesn't remove everything. It doesn't have the ability to remove fluid contamination and small bits of abrasive material.

As for more additives in the oil, there is a complex chemical structure that has to be balanced in order for oil to do all of its jobs. Adding more chemicals upsets the balance. Oil is supposed to lubricate, clean, cool and seal parts in the engine. This is a huge task that is constantly changing therefore the chemical balance has to be as perfect as man can make it.

Phil Arendt is an automotive columnist, consultant and ASE-certified master technician. E-mail him on the Web at www.drgizmo.ws.