Check out these tips and explanations from our Cars & Trucks expert--the best car and truck guy on the net!

Of course, you're also welcome to post questions to this board for more information: Just click the "Ask about Cars & Trucks" button (NOT the Answer this Question button) at the top of the page. Be sure, though, to check the list below to see if your issue is already covered.

Members: Please do not post replies in this thread. If you have a question, click on the Ask About Cars & Trucks button above.

TxGreaseMonkey

9. Radiator Fan Doesn't Run

Radiator fan failure is one of the leading causes of engines overheating, often resulting in warped aluminum heads, blown head gaskets, and damaged valves.

1. Check all under hood and under dash fuses with a test light or multimeter:

a. Multimeter. Set multimeter to DCV, turn ignition switch to ON (Position II), touch the black test lead to ground, and touch the red test lead, in turn, to each test point on the fuse. The meter should record 12+ volts. Voltage must be recorded at each test point on a fuse; otherwise, the fuse is bad.

An alternative method, which is very fast, is to set your multimeter to audible ohms, DISCONNECT THE NEGATIVE BATTERY TERMINAL (or you could blow the fuse in the multimeter), and touch the red and black test leads to the test points on each fuse. When you hear the meter buzz, you know the fuse is good. If your meter doesn't have audible ohms, but it does have ohms, you can still use this method--just read the meter instead. The alternative methods perform a continuity test on the fuse. Just remember to de-energize the circuits, by disconnecting the negative battery terminal, and record any radio activation codes first.

b. Test Light. Turn ignition switch to ON (Position II), connect alligator clip to vehicle ground, and touch the probe to each test point on the fuse. The test light must come on at each test point on a fuse; otherwise, the fuse is bad.

These methods allow you to accurately and quickly check all under hood and under dash fuses in several minutes, even in dark, cramped locations. They eliminate the possibility of removing and replacing the fuse in the wrong slot. Should a fuse test bad, use the fuse puller, provided in the underdash fuse/relay box, to remove it.

The radiator fan fuse is usually located in the under hood fuse/relay box.

2. Jump the radiator fan motor and ensure it runs. Disconnect the radiator fan motor connector and attach jump leads to the battery.

3. Check/replace the Engine Coolant Temperature (ECT) Switch, not the ECT Sensor.

4. Check/replace the radiator fan relay, which is usually located in the under hood fuse/relay box.

TxGreaseMonkey

23. "Go-To" Tools

Every mechanic has his favorite "go-to" tools. Here are a few of mine:

. High-Intensity 3 Watt LED Penlight, made by Blue-Point (ECFB200S), $46.95. Powered by 3 AAA Duracell Batteries. Unbelievably handy. It's a high-tech version of the Rayovac flashlight the Air Force issued, when I was in, to pre-flight your plane.

. 5.25" Pocket Screwdriver, Xcelite, R-183. Always with me.

. 1/4" and 3/8" Fine-Tooth Ratchets, Craftsman. Smaller tools allow easier access.

. 1/4-inch drive and 3/8-inch drive Air Ratchets, Ingersoll-Rand.

. 1/2-inch drive Impact Wrench (231C), Ingersoll-Rand.

. 1/4" and 3/8" Extension Bars, Craftsman--TRICK: 12", 18", and 24" long. Saves your back and makes working on engines much easier.

. 1/4" and 3/8" Flex Sockets, Craftsman.

. Metric Nut Driver Set, Wiha.

. SAE Nut Driver Set, Xcelite.

. Magnetic Parts Trays, Astro Pneumatic--TRICK: one for fasteners under the hood, another for fasteners under the engine. Helps to avoid confusion.

. Magnetic Pickup Tool, Lisle--used to retrieve and position fasteners.

. Digital Multimeter, Fluke 16.

. Test Light, Lisle--every vehicle owner should have one.

. Screwdriver, 24", Craftsman. Used for prying and positioning. Much handier than many would imagine.

. Drop Light, Snap.

. Vernier caliper--keep it on the top shelf of your tool chest.

There might be an idea or two, here, that will help someone.

TxGreaseMonkey

8. How to Replace Rear Wheel Bearing/Hub Assembly on a 1996 thru 2001 Ford Taurus and Mercury Sable

The following procedure is for a Ford Taurus (VIN S), with rear drum brakes and ABS. Wheel bearing noise typically develops around 100,000 miles.


1. Loosen wheel lug nuts, raise rear of vehicle, and support securely on jack stands. Block front wheels and remove rear wheels.

2. Remove brake drum (parking brake must be off).

3. Remove grease cap from hub.

4. Remove and discard hub retaining nut (36 mm). This is a compound nut, comprised of several nuts inside a metal cage. Use a 36 mm axle nut socket (e.g., OEM 25206). Many auto parts stores will lend you this socket. A 1/2-inch drive air impact wrench or breaker bar is necessary to remove the nut.

5. Remove wheel bearing/hub assembly from spindle.

6. Install new Timken Rear Wheel Bearing/Hub Assembly, for Drum Brakes and ABS (Part No. 512162). Tighten new axle spindle nut (Dorman 05114) 221 lb.-ft., replace grease cap, and button everything up.


The procedure above is similar to that used on many FWD vehicles. Obviously, sizes and torque specs will differ and some nuts may require "staking" or cotter pin replacement.

TxGreaseMonkey

9. How to Replace Lower Ball Joints, Front Wheel Bearings, and Half-Axles on a 1996 thru 2001 Ford Taurus and Mercury Sable


1. Remove hubcap, apply brakes, and loosen drive axle/hub nut (30 mm) ¼-turn with a breaker bar. Loosen lug nuts, raise vehicle, and support securely on jack stands placed under the rocker panels. Remove front wheel.

2. Remove stabilizer bar link nut (18 mm) from strut and swing link out of the way.

3. Remove brake caliper (12 mm), pads, caliper mounting bracket (15 mm), and disc. Support caliper with a piece of wire or place it on a small box.

4. Detach tie-rod end from steering knuckle, by removing and discarding cotter pin, loosening nut (18 mm) on tie-rod ball stud, and separating tie-rod end from steering knuckle with a puller. Support tie-rod on a small box so it doesn't hang.

5. Remove ABS wheel speed sensor mounting bolt (Torx E8) and move sensor out of the way.

6. Disconnect the lower control arm (LCA) from the steering knuckle, by removing the ball joint nut (21 mm) and using a ball joint separator. Removing the ball joint stud from the LCA can be a "battle royale." Here's the trick that the do-it-yourselfer needs to know: place an hydraulic jack under the subframe, remove both 18 mm subframe bolts, thread both bolts in 3 turns, and lower the subframe. Always keep the hydraulic jack under the subframe, in order to take the load off the bolts.

7. Remove axle nut (discard) and push axle from hub, using a two-jaw puller. Grasp axle shaft in one hand and pull hub and strut assembly out to separate nose of CV joint from hub. Suspend axle with a piece of wire or rest it on the LCA. Don't let it hang free, because this can overextend and damage inner CV joint.

8. Remove strut-to-steering knuckle pinch bolt (21 mm). Wiggle knuckle and hub assembly off the strut. Tap assembly off strut with a brass hammer, if necessary.

9. Remove circlip, press out and install the lower ball joint (Motorcraft MCS104217) in the steering knuckle, using a ball joint C-frame, floor press, or large machinist's vise and the appropriate receiver tubes and removing/installing adapters, and reinstall circlip.

10. Remove the three wheel bearing/hub bolts (15 mm) from the back of the steering knuckle. If the wheel bearing/hub sticks in the knuckle, pry it free.

11. Clean area on steering knuckle where wheel bearing/hub assembly seats; otherwise, it can create a lateral run out (LRO) problem with the brakes. Coat seat with high-temperature wheel bearing grease, to ease assembly and prevent corrosion.

12. Fasten new wheel bearing/hub (Timken 513100) to steering knuckle and tighten the three 15 mm bolts 70 lb.-ft.

13. Insert pry bar or large screwdriver between inner CV joint housing and transaxle case. Pry out just far enough to release the circlip. Seat pry bar on a solid surface and avoid damaging the transaxle case.

14. Support outer CV joint with one hand, grasp axle shaft with other hand, remove support wire, and guide axle clear of chassis.

15. Install new circlip on inner stud shaft spline.

16. Coat differential seal lip with multi-purpose grease, align splines of new inner CV joint (Example: Cardone Select 662008, Left; Cardone Select 662042, Right) with those on the differential side gear, firmly grasp inner CV joint housing and insert it into the transaxle. You should feel the circlip snap into place, as it seats in the differential gear.

17. Install drive axle into wheel bearing/hub. Pull out on the hub and strut assembly, align splines of outer CV joint with those on the hub, and push the outer CV joint stub shaft as far into the hub as possible by hand.

18. Install new axle nut and tighten it securely, but not fully yet.

19. Install control arm. Pull down on control arm and insert ball joint stud into steering knuckle. Install ball joint nut (21 mm) and tighten 50 to 67 lb.-ft. Raise subframe and tighten both 18 mm subframe bolts 66 lb.-ft.

20. Attach tie-rod end to the steering knuckle arm. Tighten nut (18 mm) 35 lb.-ft.; then, align the next castellation in the nut with the cotter in hole by further tightening.

21. Install disc, caliper mounting bracket, pads, and caliper. Tighten caliper mounting bracket bolts (15 mm) 65 to 87 lb.-ft. and tighten caliper bolts (12 mm) 25 lb.-ft.

22. Tighten stabilizer bar link-to-strut nut (18 mm) 62 lb.-ft.

23. Install wheel and lug nuts. Lower vehicle and tighten lug nuts (19 mm) 85 lb.-ft. Tighten axle nut (30 mm) 186 lb.-ft. Pump brake pedal several times to seat brake.


Because of the effort involved in removing the steering knuckle, it's adviseable to replace the lower ball joint and wheel bearing at the same time.

TxGreaseMonkey

13. How to Stop Vacuum Hose Leaks

Heat and ozone cause hoses to deteriorate and leak, over time. Once a vacuum hose is disturbed, particularly on older vehicles, it's prone to leak. This is particularly true on air conditioner vacuum hoses, which control diaphrams going to blender doors, where even small leaks can be disastrous.

Here's a possible solution to air vents not working properly. Separate the vacuum lines and carefully service the connections with silicone grease. This will help to recondition and restore the seal. Obviously, you must use common sense and not apply too much and plug openings.

An excellent product to use in this situation is Motorcraft Silicone Brake Caliper Grease and Dielectric Compound (XG-3-A). It's available at your local Ford or Lincoln/Mercury dealer. It's amazing the number of other applications this product can be used for; e.g., lubricating O-rings, rubber gaskets, disk brake caliper pins, radiator and heater hoses, plus using it as a dielectric compound for weatherizing battery and starter terminals and cables, main grounds, main ECM ground, ECM connectors, coils, spark plug connections, coating spark plug porcelein, and tail and brake lights. This product also helps prevent wet starting problems in seemingly small, but significant, ways. I mention these other applications, so you won't feel like you are spending money on a product with limited use. Attention to detail makes a big difference when dealing with vacuum hoses. Frequently, it's the difference between a system working or not working.

TxGreaseMonkey

11. How to Replace the A/C Compressor and Accumulator on a 1996 thru 2001 Ford Taurus and Mercury Sable, with a 3.0L Duratec Engine

This is a hard 8 hour job, even if you know what you're doing and use a lift. Many of the basic steps are applicable to most FWD cars.


1. Recover the R-134a refrigerant, by attaching a Robinair CoolTech Semi-Automatic Recovery, Recycling, and Recharging Station to the low pressure port, where the accumulator hose goes into the evaporator.

2. Disconnect the negative battery cable, remove air dam, and drain radiator.

3. Remove serpentine belt.

4. Remove old compressor from below the car:

a. Remove exhaust system, from just below the exhaust manifold to the catalytic converter. This is where 18" to 24" extensions come in handy.

b. Remove radiator cooling fan.

c. Remove lower thermostat housing and hoses.

d. Remove electrical connector to clutch.

e. Remove old compressor, by removing manifold and four mounting bolts. This provides ample room to remove and install the new compressor.

5. Optional Step: Empty the 6 oz. of Polyalkylene Glycol (PAG) refrigerant oil that came in the compressor. Instead, I added 6 oz. of BG Universal Frigi-Quiet Refrigerant Oil (Part No. 7018) to the Suction Port (S). It's a di-capped PAG oil that was strongly recommended by several people I know, who have serviced auto air conditioners in Texas for years. It can be used with R-12, R-134a, and CO2 systems and comes with a dye. I expect BG Universal Frigi-Quiet Refrigerant Oil to substantially extend the life and improve the performance of the compressor, just as other full-synthetic lubricants have already extended the life and improved the performance of my engine, power steering, and transmission.

6. Remove both O-rings from the back of the new compressor and clutch (Motorcraft Part No. YCC212). Install new O-rings, after coating them with PAG oil, to the Suction (S) and Discharge (D) ports.

7. Install new compressor and clutch--tighten four mounting bolts 18 lb.-ft. Keep the plug on the compressor ports, in order not to loose any refrigerant oil during installation. Remove plug, attach manifold, and tighten manifold bolt 15 lb.-ft. Use the original manifold bolt, not the shipping bolt securing the plug. Attach electrical connector to clutch, after applying dielectric grease.

8. Install lower thermostat housing and hoses.

9. Remove the old accumulator, by removing the A/C tube lock coupling clips and, by using the proper line separator tool, separate the spring lock couplers. One coupler (5/8-inch) connects the accumulator to the compressor and the other coupler (3/4-inch) connects the accumulator to the evaporator. Disconnect the electrical connector on the air conditioning cycling switch on top of the accumulator. Remove accumulator mounting bolts.

10. Install new accumulator (Motorcraft Part No. YF2569). Replace the three O-rings going to each connection, coat O-rings with PAG oil, connect accumulator lines to the compressor and evaporator, replace the A/C tube lock coupling clips, connect the cycling switch electrical connector (apply dielectric grease), and tighten mounting bolts.

11. Important: Rotate the three lugs on the end of the clutch several revolutions, using a pry bar, before turning the air conditioner on. This will circulate the oil in the compressor. Otherwise, the compressor may fail.

12. Attach radiator cooling fan, serpentine belt, exhaust system, negative battery cable, air dam, and refill radiator with coolant.

13. Evacuate, leak test, and charge the A/C system with 34 oz. of R-134a.

14. Test drive the car. Place a thermostat in the center cooling vent and ensure the system cools down enough. I stopped making it colder on my Taurus, when it recorded 32 degrees F.

15. Record work performed in Maintenance Log.


If there is any indication of "black death," the system should be flushed. If there is evidence of debris, the orifice tube (Motorcraft Part No. YG343) should be replaced--it will be located in the high pressure inlet tube to the evaporator, or in the liquid line, somewhere between the outlet of the condenser and the inlet of the evaporator. The point can be found, in a properly functioning system, by locating the area between the outlet of the condenser and the inlet of the evaporator that suddenly changes from hot to cold. There should be small dimples in the line that keep the orifice tube from moving.

TxGreaseMonkey

24. After Clearing Codes, How Many Miles Do You Need To Drive Before You Can Have The Car Inspected?


It's not an issue of miles--it's a function of drive cycles. Some drive cycles require a cold start, warm up, and a certain number of miles at a certain speed. So, there's no set answer. It depends on the year, make, and model of the car, along with the specific trouble code.

After a code is erased, the computer "monitors" conditions, until the drive cycle has been completed. Then, it "resets" the monitors, making it okay for inspection. There's no way to manually reset the monitors.

TxGreaseMonkey

53. Clutch Pedal Maintenance

Here's a preventive maintenance step to restore silky-smooth clutch action:

1. Remove cotter pin and clutch pivot pin.

2. Clean pin and hole of dirt and old grease.

3. Lubricate pin with synthetic grease with moly. Valvoline SynPower Grease and Amsoil Synthetic Heavy-Duty Grease NLGI #2 (GHD) are excellent choices.

4. Install pivot pin, along with a new cotter pin.

You'll appreciate the "like-new" smooth action.

TxGreaseMonkey

16. Transmission Won't Shift Out of Park

Background

Shift lock systems prevent the shift lever from moving to (R)everse or (D)rive from (P)ark, unless the brake pedal is depressed and the accelerator is in its rest position. Most shift lock systems prevent the shift lever being shifted, when the brake pedal and accelerator are stepped on at the same time. An actuator solenoid and module assembly, located on the lower portion of the steering column, locks the shifter in Park, whenever it receives a signal that the ignition key is in the ON position. When the module receives a signal from the Brake On-Off (BOO) switch that indicates the brake pedal is depressed, it unlocks the shifter so it can be shifted out of Park. The most common failures are the fuse, which also protects the cruise control deactivation circuit, and the BOO switch. If the system is not operating, check the fuse first. If it's okay, the BOO switch may be the problem. In case of system malfunction, some shift lock systems allow the shift lever to be released by pushing a key into a release slot near the shift lever. For other systems, apply the parking brake, turn the ignition key to LOCK, then remove the key. Insert the key and turn it to OFF. Press the brake pedal. Shift to Neutral, start the vehicle, and select the desired gear. You definitely want to check out these possibilities.

Suggested Approach:

1. Check all under hood and under dash fuses with a test light or multimeter:

http://www.askmehelpdesk.com/cars-tr...tml#post252145

Be thorough, since this can save a lot of time and money. Clean contacts on any fuses that don't initially pass current with abrasive cloth.

2. Verify that the brake light switch is operating properly--adjust, if necessary. Spray with WD-40 if it's hanging up. Replace, if it fails continuity.

3. Check gear shift lever adjustment.

4. Check for a faulty Automatic Transmission Gear Position Switch. These switches are relatively high-wear items, especially on older vehicles. Before replacing, though, spray with WD-40 and check adjustment.

Typical Automatic Transmission Gear Position Switch Adjustment/Replacement:

a. Remove cover and disconnect multi-pin connector from switch.

b. Remove cover switch mounting nuts.

c. Position switch slider to "Neutral."

d. Move shift lever to "Neutral," then slip switch into position.

e. Attach switch with nuts.

f. Test switch in Park and Neutral positions of shift lever. Engine should start, when shift lever is in Neutral (anywhere in the range of free play).

g. Connect multi-pin connector, clamp harness, and install console.

5. Check for a possible faulty steering lock assembly (i.e., key interlock solenoid and key interlock switch). See "Sticky," Section K.

6. Check for good contact between the connector and socket terminals.

7. Check for opens in wires and poor grounds.

Summary

Again, it's important to take a test light or multimeter and check all under hood and under dash fuses. These fuses can affect power going to the multi-pin connector and to the interlock control unit. If the problem remains, you may want to replace the interlock control unit, which may be located on the lower portion of the steering column or near the left kick panel. These are sophisticated systems that can challenge the best technicians.

TxGreaseMonkey

11. Basic Air Conditioning System Troubleshooting

Wear safety goggles and gloves when working with refrigerant. Very important: Only add refrigerant to the low side port.

1. Fuse Testing. Test all under hood and under dash fuses with a test light or multimeter.

2. Relay Testing. Verify that the compressor clutch relay and the condenser fan relay are operating properly.

3. Leak Testing. Look for obvious signs of refrigerant oil and dirt accumulation, especially around the compressor. With the A/C system on, apply Snoop or soap and water to fittings and look for bubbles. There are a host of more sophisticated dye injection kits, ultra-violet LED inspection lights, and sophisticated refrigerant sensors available to locate leaks. If it's more than just tightening a connector, the refrigerant will need to be recovered and the component replaced. Once the system is opened, it's best to replace the accumulator and orifice tube found on most GM and Ford models. Similarly, it's best to replace the receiver-drier and thermal expansion valve (TXV) found on most imports, when the system is opened. Replace O-rings on all new components and leaking connections, coating them with PAG oil. Afterwards, the system will need to be evacuated (vacuum pumped for 40 minutes at 28 in-Hg) and recharged. The static pressure test, below, will help assess whether there is a leak--it won't help you locate it, however.

4. Pressure Testing. A manifold gauge set (U.S. General, $40, Harbor Freight) is essential to troubleshooting and maintaining air conditioning systems. Never attempt to add refrigerant without using a manifold gauge set. It’s imperative to obtain information about what’s happening inside the system first. Without a manifold gauge set, you don’t know how much refrigerant, if any, that needs to be added. By using the proper equipment, you prevent overfilling the system and destroying the compressor, by monitoring the high and low system pressures. Here’s how to attach the hoses:

. Connect the low side (blue) hose to the low side port on the A/C unit.

. Connect the high side (red) hose to the high side port on the A/C unit.

. Connect the center service (yellow) hose to the refrigerant cylinder, while charging, or to the vacuum pump, while evacuating air and moisture.

A. Static Pressure Test (both hand valves closed). An initial pressure reading indicates if the system has enough pressure to satisfy the low pressure switch and enable the compressor to operate. Most low pressure cut off switches turn the system off at approximately 20 psi. Compressors will not normally function until the pressure reaches 45 psi. Therefore, you need a static pressure of at least 45 psi, before the compressor will normally operate. Static pressure is also used to determine if a system has enough pressure to begin leak testing (50 psi minimum).

B. Low Side and High Side Pressure Test (both hand valves closed). Start the engine and allow it to reach normal operating temperature. Turn the A/C system on and set it to “max/high” output. With an engine speed of around 1,000 rpm, check the low side reading, which should be 25 to 35 psi. Next, check the high side reading, which should be about 200 to 350 psi. WARNING: Never open the high side hand valve, while the air conditioning system is operating. It’s best to consult a manual for the recommended pressures for your vehicle. On my 1993 Civic, for example, the low side pressure is 36 psi and the high side pressure is 320 psi. On my 2000 Ford Taurus (FFOT), depending upon the clutch cycle switch, the low side pressure is 22 to 45 psi, while the high side is 125 to 230 psi. These pressures are at 80 degrees F and at sea level.

If the readings are lower than normal (with both manifold hand valves closed), attach a can of refrigerant to the yellow service hose, loosen the center hose on the manifold gauge set and allow a small amount of refrigerant to escape to purge air and moisture from the center hose, retighten the center hose connection, open the hand valve to the low side of the manifold, and add enough refrigerant to bring the readings up to the normal ranges. WARNING: If the low side service port isn’t on the accumulator, keep the refrigerant container in an upright position, permitting charging with refrigerant vapor only. Afterwards, close the manifold gauge set low side hand valve and the refrigerant supply valve. Even though the above approach is the most common and expediant approach, it's best to evacuate and vacuum the system before recharging. This allows you to recharge the system with the precise amount called for the vehicle. I use a U.S. General Vacuum Pump ($70, Harbor Freight), filled with Robinair vacuum pump oil.

C. Compressor Test. A bad compressor will normally show the inability to generate enough suction and pressure at idle speeds. If the engine speed needs to be increased substantially to bring pressures in range, it's a sign the compressor is weak. The typical complaint is, "It only cools when the engine is revved or when driving down the road." It's often simple. If we hook, for example, the gauges up and see 80 psi on the low and high sides and the compressor hub is spinning, the compressor is shot. It's not producing suction or pressure. We could add more refrigerant and nothing would change. Compressors must be able to pull a vacuum and create pressure.

D. Final Performance Test. Place a thermometer in the far right air conditioning outlet, with the air conditioning controls set to their maximum cooling position. Adjust the blower speed to low and allow the system 5-minutes to stabilize. The thermometer should read 35 to 45 degrees F, at approximately 75 to 80 degrees F outside temperature. If you notice, after driving the vehicle for a while, that air stops coming out of the vents, the A/C clutch cycling switch may be bad. The cycling switch is supposed to control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing. Instead, it may be energizing the clutch too much and the system is icing up. In this situation, simply unscrew the old cycling switch from the Schrader valve-type fitting on the accumulator, coat the threads and O-ring with PAG oil, and install the proper cycling switch. It is not necessary to discharge the refrigerant system to remove the switch. The cycling switch's cut-on and cut-off pressures are readily available in manuals; therefore, its operation can be monitored by the manifold gauge set and you can tell whether its working properly or not.