Can I replace the clutch myself?

You can if you have the proper tools and know-how. Changing a clutch is a big job on a rear-wheel drive car or truck, and an even tougher job on a front-wheel drive car or minivan.

On a rear-wheel drive vehicle, the driveshaft, transmission and bellhousing have to be removed from underneath the vehicle to get at the clutch. The clutch can then be unbolted from the flywheel and replaced. Resurfacing the flywheel is recommended -- and required if the flywheel is warped, grooved, badly worn, heat discolored and/or contaminated with grease or oil. That means the flywheel has to come out, too. If the flywheel is cracked, it should be replaced.

In addition to replacing the clutch, a new throw-out bearing is also recommended. Considering the labor involved to tear everything apart, it's risky to reuse an old throw-out bearing. It may not be noisy now, but it's hard to tell how many miles it might have left in it.

The pilot bushing in the end of the crankshaft that supports the transmission input shaft should also be inspected. Replacement is recommended if your vehicle has a lot of miles on it.

Reinstalling the transmission is the most difficult part of the job because the transmission is heavy (which means you'll need a floor or transmission jack, or a pair of strong arms). The clutch must also be perfectly aligned (with a pilot tool) so the transmission input shaft will slip into place, once everything has been bolted together.

With front-wheel drive, replacing the clutch is even more difficult because it involves pulling the engine or dropping the transaxle (both of which are major undertakings because of all the disassembly that's involved). For this, you'll need an engine hoist to pull the engine or a hoist or beam to support the engine from above while the transaxle comes out.

When I try to start my engine, I hear a clicking sound but nothing happens. Do I need a new starter?

Maybe, but the only way to know for sure is to check out the battery, solenoid and starter. If you hear a clicking noise, it means voltage is getting through to the solenoid. But there may not be enough voltage to spin the starter. So start with the battery and cables.

Is the battery at full charge? Are the battery cables clean and tight? Be sure to check both ends. Are the other electrical connections at the solenoid and starter clean and tight? It doesn't take much corrosion to choke off the flow of amps to the starter.

Next, check the wiring connections on the solenoid and starter. Are they clean and tight? Also check the solenoid ground connection or its mounting. Rust or corrosion here can interfere with the flow of amps, too.

Try bypassing the solenoid to see if the starter spins. If it spins, the problem is excessive resistance in the solenoid. Replace the solenoid. If the starter doesn't spin, or turns very slowly, however, the starter is dragging and needs to be replaced.

My engine starts and idles fine, but lacks power at high speed. What's wrong?

You most likely have one of two problems: a fuel line restriction or an exhaust restriction.

Fuel Restriction

A plugged fuel filter, crushed fuel line or clogged pickup screen inside the fuel tank can all starve your engine for fuel. Enough fuel may get through for the engine to start and run at low speed, but when more fuel is needed it can't get through resulting in loss of power at high speed. The same kind of problem can also be caused by a weak fuel pump. But fuel pumps usually quit altogether when they fail.

Inspect the fuel line from the tank to the engine. If you don't see any obvious damage, try replacing the fuel filter. If that doesn't help, blowing out the fuel line with compressed air from the engine towards the fuel tank may help dislodge a blockage and debris from the pickup screen. If the pickup screen in the tank is clogged with rust and debris, the tank will have to be removed so the screen can be replaced and the tank cleaned.

Fuel pressure can also be checked by teeing a suitable gauge into the fuel line. If pressure is very low (refer to a manual for the specs), the pump probably will need to be replaced.

Exhaust Restriction

As for an exhaust restriction, the easiest way to check for this condition is to hook up a vacuum gauge to a vacuum port on the intake manifold or throttle body. If vacuum is low and continues to drop as the engine runs, it's telling you pressure is backing up because of a restriction in the exhaust. The most likely culprit is a clogged catalytic converter.

If the converter has overheated, it may have melted internally. This would restrict the flow of gases through the converter and create a serious backpressure problem that would cause a loss of power at high speed. If the blockage is complete, the engine may start then die and not run at all.

Other causes here may include a crushed exhaust pipe (a visual inspection should find this easy enough), a double-walled pipe that has collapsed internally, or a muffler that has become clogged with rust (rare, because they usually blow out). If you suspect an exhaust restriction, temporarily disconnect the head pipe from the catalytic converter (which is no easy task because the bolts will probably be rusted solid). If the engine now runs normally, you have an exhaust restriction. Inspect the converter and replace it if needed.

NOTE: If the converter is plugged, it failed because something else caused it to overheat. Causes include misfiring spark plugs and leaky exhaust valves. The underlying problem needs to be identified and corrected before the converter is replaced otherwise the new converter will suffer the same fate.

I have a manual transmission. Does the fluid in it ever need to be changed?

Not usually. Some older import vehicles (like Volkswagen Beetles) recommended periodic lube changes for their gearboxes, but no modern car or light truck requires it. The reason why is because the oil stays relatively clean and runs fairly cool. Unlike the fluid in an automatic transmission that is being constantly churned (which generates heat) and contaminated by particles worn off the clutch plates, the fluid in a manual transmission or transaxle has life pretty easy. So it usually lasts the life of the transmission.

The only reason you might have for changing it would be if you were experiencing hard shifting problems during cold weather. Most older rear-wheel drive transmissions use a heavy gear oil like 75W, 80W or 90W, which can get pretty stiff at subzero temperatures. Changing to a lighter oil may improve shifting.

Most manual transaxles in front-wheel drive cars today use Dexron II automatic transmission fluid (ATF) to keep the gears lubed. ATF works well because it stays much more fluid at low temperatures. But ATF should not be substituted for gear oil. Always use the type of lubricant specified by the vehicle manufacturer.

Adding Oil

The only time you should have to add oil to a manual transmission or transaxle is if the tranny is leaking oil. If you see any grease or wetness around the tailshaft or driveshaft seals, the oil level in the transmission or transaxle should be checked because it may be low. WARNING: Allowing the transmission or transaxle to run too low on lubricant can ruin it.

My engine starts but dies after a couple of minutes and won't restart. What's wrong?

It sounds like the classic symptom of an exhaust blockage, probably due to a clogged catalytic converter. The converter can overheat and be damaged if excessive amounts of unburned fuel enter the exhaust system. This can happen if the engine has one or more fouled spark plugs or leaky exhaust valves. When this unburned fuel hits the converter, it sends temperatures soaring. The ceramic substrate or pellets that support the catalyst can melt and partially or completely block the flow of exhaust through the converter.

If a complete blockage occurs, the engine will start normally but the exhaust has no place to go. Backpressure quickly builds up and within a couple of minutes the engine quits running. Eventually, the pressure will seep out and allow the engine to restart after it has sit for some time. But the blockage will prevent it from running for long.

The cure here would be to replace the converter. But first, the underlying problem that caused the converter to overheat and fail needs to be diagnosed and corrected -- otherwise the new converter will suffer the same fate.

Other possible causes of this kind of condition include a crushed exhaust pipe, some prankster shoving a potato up your tailpipe, a collapsed inner wall in a double-walled head pipe, or a muffler that's obstructed with rust debris.

My engine is hard to start when it's cold. What's wrong?

If your engine has a carburetor, the hard starting problem is most likely choke related. If the engine cranks normally and the spark plugs are not worn or dirty, the choke probably needs to be repaired or adjusted.

The choke may be set too rich or too lean. Either way can cause hard starting. Inside the choke housing is a bimetal spring that regulates the tension on the choke according to temperature. If this spring is broken, the choke will not operate. If the choke linkage is rusty or jammed with varnish deposits or dirt, it may stick or not operate smoothly. Cleaning with carburetor spray or solvent may help alleviate a sticking problem.

On older fuel injected engines, a separate "cold start" injector is used to spray additional fuel into the intake manifold when a cold engine is first started. If this injector is not working, the engine can be hard to start. The injector is controlled by a timer and relay, so if either of these components is defective it can prevent the cold start injector from doing its job, too.

If your engine cranks slowly, your cold starting problem is not fuel related, but may be due to a weak battery, loose or corroded battery cables, or a weak starter.

Check for obvious problems first. Remove, clean and inspect the battery cables (both ends). Then check battery charge and condition. (More information on the condition of your battery and battery recharging is available.) If the battery charge is low, recharging the battery may temporarily solve your problem. But there's a reason why your battery is low. You probably have a charging system problem that requires further diagnosis. (More information on alternators is also available.) If your battery is more than four or five years old, it is probably near the end of its service life and needs to be replaced. A "load test" will tell you if it still has sufficient cranking capacity to provide reliable cold starting.

Slow cranking during cold weather (below freezing) can also be caused by oil that is too thick. A high viscosity oil such as straight 30 or 40 weight oil in the crankcase can make an engine very difficult to crank when the temperature drops. Switching to a lighter multiviscosity oil such as 10W-30 or 10W-40 should solve this problem.

When I try to start my engine, nothing happens. It won't even crank. All I hear is dead silence. What's wrong?

Assuming you're not deaf, you have a starting problem that may be due to a dead battery, a loose or corroded battery cable, a bad ignition switch, an open neutral safety switch, or a bad solenoid or starter.

Total silence usually means no juice is getting through to the starter. So start with the battery. Is is dead or does it still have a full charge? Are the battery cables loose, corroded or damaged? Be sure to check both ends of the cables, including the starter and ground connections.

If you don't find any obvious problems with the battery or its connections, voltage may not be passing through the ignition switch circuit to the starter solenoid. A voltmeter or 12 volt test light can help you see if voltage is reaching the solenoid when you turn the key.

If voltage isn't getting through, try jiggling the gear shift lever. Some vehicles may also have a safety switch on the clutch pedal that prevents the engine from starting unless the clutch pedal is depressed. Use your voltmeter or test light to isolate the component that needs to be replaced or adjusted. Sometimes the transmission or clutch linkage may need to be adjusted for the safety switch to work properly.

If voltage is getting through the ignition switch circuit, but the starter isn't doing anything, check the wiring connections on the solenoid and starter. Are they clean and tight? Try bypassing the solenoid. Refer to a shop manual for the proper terminals, then jump the one that routes voltage directly to the starter (usually B+ or BAT). If the starter spins, the problem is a bad solenoid (or poorly grounded solenoid). If nothing happens, the problem is a bad starter that needs to be replaced.