Dayton Daily News

Q The heater in my 2000 Infinity I30 does not blow hot air unless the car is accelerating. After two visits to a shop, my mechanic replaced the thermostat and the radiator, all to no avail. Now he thinks the trouble is caused by the water pump. This not only is frustrating, but it's getting expensive. What's the trouble? G.E., e-mail

A This could be caused by the failure of the water pump impeller due to corrosion. To determine the cause, he could perform a coolant flow test if he has the equipment to do so. If not, he needs to remove the water pump to inspect it. If the impeller is damaged by corrosion or another fault, replacement will increase coolant flow and perhaps increase the efficiency of the heater.

What's troubling is normally the engine temperature rises and may overheat when the water pump is not pushing a large volume of coolant through the system. If he replaced the thermostat and radiator for this reason, the water pump is suspect of failure. Replacement is the cure for this problem, but if the engine temperature is normal and the heater is not supplying sufficient heat, there likely is a problem in the heater core, control circuit or vacuum controls. Also, there might be air trapped in the heater core.

Talk this over with your favorite mechanic before making a decision to replace the water pump.

Poor starts mix gasoline with oil

Q My 2000 Chevrolet Blazer with a 4.3-liter engine is difficult to start. At first I replaced the battery because it failed tests. I also replaced the spark plugs, but the engine wouldn't crank, so I had the starter tested and it was found faulty. I replaced it, and the engine still doesn't start. Also, the oil pressure is lower than it used to be. The oil level is way over the full mark, and the oil smells of gasoline.

I had the oil changed last December where I purchased the vehicle. I've only driven 10 times since then. I read in the owner's manual that if the oil level is overfilled, the engine can be damaged. Is this true? What should I do? C.H., e-mail

A The fact that the oil level is way over the full mark may be the result of trying to start the engine, without success. This can flood the cylinders with gasoline, which in severe cases causes gasoline to enter the oil pan to mix with the oil. Changing the oil and filter is necessary. Gasoline in the oil could have disastrous effects on bearings as the oil no longer has the ability to properly lubricate.

It's also possible that all of the starting trouble is caused by a faulty fuel pressure regulator. When this part fails, it has a tendency to leak fuel into the engine, and the engine won't start due to a lack of fuel pressure. If this is the cause of the trouble, replacement of the regulator, along with an oil and filter change, is the cure. In fact, the oil and filter should be changed more than once before driving the vehicle but after the engine has been run for a while at an idle. Then it should be changed again after the vehicle has been driven a day or two. This will help prevent engine damage and remove any residual gasoline that has accumulated in the engine.

Computer Test Will Find Cause Of Misfire

Q My 2002 Chevy 2500HD truck with 42,000 miles is giving me some problems. I start the 6.0-liter engine and start to drive but the engine stalls. After I restart and drive a short distance the check engine light flashes. When this happens I pull over and shut off the engine. When I restart the engine runs normally. This has happened about six times.

I took the truck to my local shop. The technician says that cylinders 2, 4, 6 and 8 are misfiring. All of these cylinders are on the same side of the engine. What's the cure? S.D., E-mail.

A It's time to junk the truck. Of course I'm kidding. The trouble could be the result of a lack of fuel to the cylinders on that side of the engine. A test of the fuel pressure and tests of the fuel injectors might verify this.

The repair may be as simple as cleaning the injectors or perhaps there is an electrical issue such as a faulty ground connection that causes the injectors to malfunction. Maybe the fuel pressure regulator or fuel pump is not functioning as designed.

It's also possible that the spark plugs or spark plug wires are in need of replacement but it's more likely there is another issue.

Computer diagnostic tests should lead a technician to the source of the trouble. With a little probing he should be able to pinpoint the cause of this trouble.

Needs Radio Suppressor

Q The radio reception in my 1997 Ford Explorer with about 95,000 miles has very poor reception on the lower half of the AM band. The reception is poor and there is a lot of static. The upper half of the AM band is fine. Also, FM reception is fine. The static interference stops when I turn off the engine.

I am tempted to replace the wiring harness but I am looking for other ideas. I spoke with personnel at my local dealer but no one has a solid recommendation. Can you help? D.J., E-mail.

A Play C/Ds. All kidding aside, the trouble may be caused by interference from the fuel pump electrical harness. With the radio turned on turn off the engine and ignition key. After a minute or two, turn the ignition on to the accessory position without starting the engine. If interference is heard only for a short time when the electric fuel pump is running it's likely the electrical harness to the fuel pump is emitting static and noise. If this is the cause installation of a radio interference suppressor may end your concerns.

A dealership parts counter person can set you up with the parts you will need for this installation or you can ask a technician to handle the job for you.

Battling Battery Terminal Corrosion

Q My neighborhood kid has a 1991 Toyota truck with a 4-cylinder engine and a 5-speed manual transmission. Both battery terminals develop corrosion every few days. He has replaced the cables, battery and fuse box. He also installed an extra ground wire. Despite this corrosion develops within a few days.

It's obvious to me that something is not properly connected or there is reverse polarity. What should he do? B.R., E-mail.

A You could buy him a new truck. I'm just kidding, again. This likely isn't a case of reverse polarity or improper electrical connection. If it were he'd have many other issues with the truck such as it won't run.

The trouble with corrosion is that once it starts it's almost impossible to eliminate and prevent. Despite this he can thoroughly clean the battery terminals and battery posts inside and out with a solution of baking soda and water. Once everything is as dry as a bone he should use sand paper or specialized battery cable clamp and post cleaning tool to remove a thin layer of metal from the connections. Once this is accomplished clean the terminals again with baking soda and water. He should also clean the exterior of the battery using caution not to get any of the cleaning solution in the cells.

Once everything is dry he should connect the cables to the battery terminals and apply anti-corrosion compound to the exterior of the connections. He can purchase everything he needs from an auto supply store. Also, many Toyota dealer parts departments sell battery terminal anti-corrosion compound.

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