Auto Part Tips


Smyth Automotive is always interested in getting our customers the best tips and advice in auto parts. Please use the below tabs to find the project you need to know. If you can’t find the information here email

Air Conditioning

Low Compressor Discharge Pressure

1. Leak in system
2. Defective expansion valve
3. Suction valve closed
4. Freon shortage
5. Plugged receiver drier
6. Suction valve leaking
7. Bad reed valves in compressor
1. Repair leak in system
2. Replace valve
3. Open valve
4. Add freon
5. Replace drier
6. Replace valve
7. Replace reed valves

High Compressor Discharge Pressure

1. Air in system
2. Clogged condenser
3. Discharge valve closed
4. Overcharged system
5. Insufficient condenser air
6. Loose fan belt
7. Condenser not centered on fan or too far from radiator
1. Recharge system
2. Clean condenser
3. Open valve
4. Remove some refrigerant
5. Install large fan
6. Tighten fan belt
7. Center and check distance

Low Suction Pressure

1. Refrigerant shortage
2. Worn compressor piston
3. Compressor head gasket leaking
4. Kinked or flattened hose
5. Compressor suction valve leaking
6. Moisture in system
7. Trash in expansion valve or screen
1. Add refrigerant
2. Replace compressor
3. Replace head gasket
4. Replace hose
5. Change valve plate
6. Replace drier
7. Replace drier


High Suction Pressure

1. Loose expansion valve
2. Overcharged system
3. Expansion valve stuck open
4. Compressor reed valves
5. Leaking head gasket on compressor

1. Tighten valve
2. Remove some refrigerant
3. Replace expansion valve
4. Replace reed valves
5. Replace head gasket

Compressor Not Working

1. Broken belt
2. Broken clutch wire or no 12v power
3. Broken compressor piston
4. Bad thermostat
5. Bad clutch coil
6. Low Refrigerant – low pressure switch has cut off clutch power
1. Replace belt
2. Repair wire or check for power
3. Replace compressor
4. Replace thermostat
5. Replace clutch coil
6. Add refrigerant

Evaporator Not Cooling

1. Frozen coil, switch set too high
2. Drive belt slipping
3. Hot air leaks into car
4. Plugged receiver drier
5. Capillary tube broken
6. Shortage of refrigerant
7. High head pressure
8. Low suction pressure
9. High suction pressure
10. Defective expansion valve
11. Frozen expansion valve
1. Turn thermostat switch back
2. Tighten belt
3. Check for holes or open vents
4. Replace drier
5. Replace expansion valve
6. Add refrigerant
7. See problem #2
8. See problem #3
9. See problem #4
10. Replace expansion valve
11. Evacuate and replace drier

Frozen Evaporator Coil

1. Faulty thermostat
2. Thermostat not set properly
3. Insufficient evaporator air
1. Replace thermostat
2. Set to driving condition
3. Check for excessive duct hose length, kink or bend.
Belts & Hoses

Periodically replacing your belts & hoses helps avoid overheating and other serious engine damage

Belt and hose service includes:

  • A thorough visual inspection of all belts and hoses for evidence of wear or damage
  • Replacement of all worn belts and hoses as needed
  • Adjusting the fit of installed belts, hoses, and related components

Why is it important to replace my vehicle’s belts & hoses?

Replacing belts and hoses at the first sign of wear helps avoid unexpected breakdowns and the engine damage that overheating can cause. More specifically:

  • Leaking or ruptured coolant hose(s) can result in an overheated engine or a vehicle breakdown
  • Power steering hoses are critical to safe vehicle operation
  • A broken or worn-out belt can leave your vehicle inoperable

How do I know when it’s time to replace my belts and/or hoses?

Belts and hoses are critical parts of your engine and cooling system. To avoid problems, your hoses should be checked at every oil change. Belts generally need to be replaced every 30,000 mi — 60,000 mi (50,000 km —100,000 km).

Signs that you should have your belts checked include:

  • Cracks in the belt material
  • Splitting, peeling or fraying belts
  • You engine sounds like it’s running rough or stalls out at a stop
  • You hear knocking or pinging sounds when accelerating or after the ignition is turned off
  • Your check engine light remains on after your initial start

You should have your hoses checked if you notice any of the following:

  • Bulging or inflated hoses
  • Hardened or inflexible hose material
  • Cracks along the hose
  • Worn or corroded hose clamps
Brake Pads & Shoes

With the vehicle at rest, apply steady pressure to the brake pedal.

Does it feel spongy? If so, you probably have air in your brake lines. Correcting this problem isn’t difficult; unless your brakes have ABS or other sophisticated brake systems, you can probably do the job yourself with the help of a friend.

Does the pedal stay firm when you continue applying pressure, or does it seem to sink slowly to the floor? If the pedal sinks, your master cylinder may be defective, and that’s unsafe.

Release the parking brake and drive around the block, stopping every now and then.

Notice how much effort is required to bring your vehicle to a stop. With power brakes, the pedal should stop 1 to 1-1⁄2 inches from the floor. (If you don’t have power brakes, the pedal should stop more than 3 inches from the floor.)

If your vehicle has power brakes and stopping seems to take excessive effort, you may need to have the power booster replaced.

If you feel that your brakes are low, pump the brake pedal a couple of times as you drive around.

If pumping the pedal makes the car stop when the pedal’s higher up, either a brake adjustment is in order or you need more brake fluid.

If the level of brake fluid in the master cylinder is low, buy the proper brake fluid for your vehicle and add fluid to the “Full” line on your master cylinder. Check the fluid level in the cylinder again in a few days.

If you find that you’re not low on fluid, drive carefully to a service facility and ask them to remedy the situation. When they’ve worked their magic, the pedal shouldn’t travel down as far before your vehicle stops.

Disc brakes self-adjust and should never need adjusting. Drum brakes also have self-adjusting devices that should keep the drum brakes properly adjusted. If any of the self-adjuster components on drum brakes stick or break, the drum brakes won’t adjust as they wear out, resulting in a low pedal.

As you drive around, notice how your total brake system performs, and ask yourself these questions:

Does the vehicle travel too far before coming to a stop in city traffic? If it does, either your brakes need adjusting or you need new brake linings.

Does the vehicle pull to one side when you brake? On vehicles with front disc brakes, a stuck caliper and brake fluid leak can cause this problem.

Does your brake pedal pulsate up and down when you stop in a non-emergency situation? A pulsating brake pedal usually is caused by excessive lateral run-out, which can happen because your brakes are overheating from overuse.

Does your steering wheel shake when you brake? If it does and you have disc brakes, your front brake discs need to be professionally machined or replaced.

Do your brakes squeal when you stop fairly short? The squealing is a high-pitched noise usually caused by vibration. Squealing can occur when the brake linings are worn and need replacement, the brake drum or disc needs to be machined, the front disc brake pads are loose or missing their anti-rattle clips, the hardware that attaches the brake calipers is worn, or inferior brake linings are in use.

Do your brakes make a grinding noise that you can feel in the pedal? If so, stop driving immediately and have your vehicle towed to a brake repair shop. Further driving could damage the brake discs or drums. Grinding brakes are caused by excessively worn brake linings; when the lining wears off, the metal part of the brake pad or brake shoe contacts the brake disc or drum and can quickly ruin the most expensive mechanical parts of the brake system.

Does your vehicle bounce up and down when you stop short? Your shock absorbers may need to be replaced.

Never put off brake work. If this check shows that you have a problem, take care of the situation immediately. If your brakes fail, you (and other people) may be in serious trouble. Other kinds of automotive trouble may keep your vehicle from moving, but brake trouble keeps it from stopping.



  • Check magnetic drain plug for particles and examine.
  • Check magnetic screens.
  • Drain oil through a fine cloth or sieve.
  • Drain oil and flush if necessary to clear system.
  • Check operation of system (e.g. noise, vibration, oil pressure etc.)
  • Thief sample drawn from bottom of the sump.
  • Not sampled hot and midstream at drain (see sampling instructions).
  • Check correct oil level is being maintained.
  • Check correct oil grade is being used.
  • Lack of/excessive particles can result from cold sampling procedure as oil is not well mixed.
  • Debris could come from a previous failure or an accumulation of wear particles.
  • Check shaft alignment.
  • Check diff lock operation.
  • Oil pump not operating.
  • Extended lubricant use.
  • Check for misalignment of drive train.
  • Check tyre diameters are the same size.


  • Check for leaking oil seals.
  • Check for damaged or missing breathers.
  • Loose cover plates or linkage boots/seals damaged.
  • Oil storage or top-up containers/funnels dirty.
  • Dirt entering when unit filled or topped up with oil.
  • Pressure cleaning procedure introducing water or dirt.
  • Condensation due to low operating temp. or blocked breather.
  • Oil cooler leaks.
  • Check sampling technique.
  • Recent overhaul/rebuild


  • Sump overfull.
  • Heat transfer (e.g. binding brakes).
  • Low oil level.
  • Unit caked with dirt.
  • Oil cooler blocked or restricted.
  • Incorrect oil grade.
  • Overload conditions.
  • Shaft misalignment.
  • Localized high temperature due to wear problem.
  • Diff lock left engaged for extended periods
– Batteries
– Alternators
– Starters
– Battery Cables
– Wiper Motors
– Window Motors & Regulators
– Engine Brearings
– Gaskets & Seals
– Harmonic Balancers
– Manifolds
– Engine Mounts
– Pistons & Rings
– Oil Pumps
– Timing Chain & Kits
– Valve Train & Camshafts
– Exhaust Pipes
– Mufflers
– Catalytic Converters
Fuel & Emission
– Carburetors & Parts
– Fuel Pumps
– Fuel Injectors
– A.I.R. Pumps
– Electronic Controls
– Fuel Tanks
– Gas Caps
Ignition & Engine Filters
– Distributors
– Filters
– Spark Plug Wires
– Ignition Coils & Modules
– PCV Valves
Steering & Suspensions
– Coil Springs
– Shocks & Struts
– Strut Mounts
– Power Steering Pumps
– Power Steering Hoses
– Ball Joints/Control Arms
– Tie Rod Ends
– Rack & Pinion/Steering Gear
Vision & Safety
– Wiper Motors
– Window Motors & Regulators
– Headlights & Bulbs
– Flashers
– Washer Pumps
– Lenses
– Wiper Blades