Safely Working in the Engine Bay

There are some basic safety precautions that you should take when working in the engine bay of your vehicle.

Safety Equipment Checklist:

1. Safety glasses - always wear safety glasses or goggles to protect your eyes from debris or chemicals.
2. Chemical resistant gloves - to protect your hands against chemicals.

General Precautions:

1. The engine contains many moving parts. Work with the engine off unless its necessary.
2. Connect the vehicle exhaust to an exhaust evacuation system or park outside – carbon monoxide is a deadly gas.
3. Park in gear and apply hand brake.

Engine Wont Start

Engine Won’t Start or Problems Starting Engine

Summary: Car won’t start, general engine starting problems, faulty alternator or starter motor?

If you’re having trouble starting your car, van, lorry, boat, industrial or agricultural application, there could be a number of faulty engine parts causing the problem. This short guide will help you to identify an alternator problem or a faulty starter motor.

First Things First – Tell Tale Signs

Turn detective and look for evidence of a faulty alternator or starter motor. If you’re experiencing any of the following then a problematic alternator or starter motor may be the cause.

Common Symptoms of Alternator & Starter Motor Failure

•    Abnormal noises, such as knocking sounds or clicking
•    The engine is not turning over at all
•    The engine struggles to turn over
•    Nothing happens when you turn the key i.e. ignition doesn’t come on
•    The engine cut out whilst you were driving
•    Some electrical systems stopped working e.g. car radio or lights
•    The lights are shining less brightly than usual
•    A flat battery

Proceed to Testing

If you can identify with any of the symptoms above then it’s possible that you have a faulty alternator or starter motor. The next logical step is to test your alternator or test your starter motor. Our testing guides follow a systematic approach and will enable a correct root problem diagnosis.

Next Step: Visit our alternator testing or starter motor testing

Flat Car Battery - Causes & What to Do

Do you have a Flat Car Battery?

A flat car battery is not the same thing as a faulty battery. Battery failure is usually caused by one of two things: Alternator Failure or a Faulty Battery. This articles covers the symptoms and causes to enable a swift resolution to your problems. It's possible that your car needs a replacement alternator.

Symptoms of a Flat Car Battery

There are a couple of tell tale signs that your battery might be faulty:

1. Dim or dull headlamps
2. Engine turns over slowly when starting
3. The engine stops

What to do - Battery Testing

The best way to test your battery is to attempt to jump start the vehicle. If your car will start using a set of jump leads, this strongly indicates that your battery is flat. If you have any doubts or the results are inconclusive, have your battery tested by a professional.

If you identify that you have a flat battery, please note that replacing your battery might not cure the problem. If your car battery keeps going flat, conduct a thorough Alternator Test.

Flat Battery Causes

There are two possible causes of a flat car battery:

1. Alternator Failure

The alternator is responsible for charging the battery on your vehicle. If the alternator becomes faulty it will not provide enough charge and this will inevitably cause battery failure.

Using our simple 4 step alternator testing procedure, find out whether the alternator is causing your battery to go flat.

2. Faulty battery


If you are satisfied that your alternator is working correctly, it may be that your battery is faulty and needs replacing. This can be caused by anything from cold weather, to your batteries age. It is advisable to have your battery checked by a professional to confirm this.

Simple 4 Step Alternator Testing Guide

Is My Alternator Faulty? How to Test an Alternator in 4 Simple Steps...

Our ‘How to Test an Alternator in 4 Simple Steps’ guide provides four basics checks that will assist your diagnosis of alternator problems. If your vehicle passes the following alternator tests, your alternator might not be to blame. Some of the following common effects of failure are:

• My engine wont start / car wont start
• Battery is flat
• Battery warning light stays on / not working properly

Our Alternator testing procedure couldn't be easier. Following our three step alternator tests in a methodical order ensures fault detection as early as possible and covers car, marine, commercial, plant & agricultural applications.

Step 1: Check the Fan Belt Tension

Approximately 10% of alternators are replaced incorrectly due to inadequate diagnosis – when in fact a replacement alternator drive belt (fan belt) may have fixed the problem. If the alternator belt is slipping, it will not drive the alternator – and hence charge the battery properly.
Test: Find your recommended fan belt tension in the vehicle service manual. If the belt is too loose, adjust accordingly and see whether this provides a fix to your problem.

Step 2: The Alternator Volt Meter Test

Test: the alternator using a standard multimeter. To perform this test you need to measure the voltage across your battery. This is achieved by placing the positive (red) probe on the positive battery terminal - and the negative (black) probe on the battery negative terminal.

Set the device to the DC scale and with the engine running, measure the voltage. With the engine idling, we would expect to see at least 14 volts, which suggests that the alternator is charging the battery sufficiently. Any reading below 14v requires further investigation, so move on to the next test.

Step 3: Test the Alternator B+ Cable

The B+ thick cable connection allows the alternator to pass charge to your battery. This is therefore a crucial component of the electrical setup, because without continual charge the battery will go flat!

Test: Using your multimeter on the DC setting, place one probe on the B+ terminal on your alternator - and the other on the battery negative terminal (It doesn't matter which way round). The reading should be similar to that measured in step 2 at over 14 volts. If there is a significant variation between the two results, this indicates a break in the wiring and further investigation is required. Otherwise proceed to step 4... 

Step 4: Test the Alternator Warning Bulb & Wiring

The battery warning light alerts you to a possible alternator problem. Under normal conditions the battery light glows when the ignition is turned on - and disappears when the engine is started.
Quick checks: If your battery warning light is not working at all, it might just be the bulb. If your battery light continues to glow when the engine is running, this signifies a problem with the alternator.
Test: With the ignition on – the battery warning lamp should glow. If your bulb doesn't glow you will need to locate and disconnect the lamp terminal (connection D+ L in the above diagram). Using a standard voltmeter (multimeter), test the voltage on the lamp wire (with the ignition on). You should discover a reading of 12 volts, which disappears when the ignition is turned off.

Note: If there is 12V on the lamp wire, and you have completed this 4 step testing guide, then the bulb is fine and the alternator must be faulty.

Need a Replacement Alternator

If you found anything suspicious and would like further expert guidance feel free to contact us on 0845 564 2681. Alternatively visit the alternator section of our store to find a replacement alternator today.

3 Step Starter Motor Testing Guide

Starter Motor Problems?

If you car won’t start or struggles to fire up, this could indicate starter motor problems. There are three basics checks that will assist your diagnosis. And, if your vehicle passes the following 3-point test, your starter motor might not be faulty after all.

Starter motor problems can cause the obvious side effect of an engine that wont start or struggles to start. Simply follow our three step starter motor testing procedure in a methodical order to ensure fault detection as early as possible.

Step 1: Check the Battery

Make sure your battery is well charged. If you have any doubts, try jump starting the engine. If your engine starts using the jump leads, you may well have a flat battery rather than a faulty starter motor. In this case get a qualified mechanic to test your battery.
Battery Test: If the car started with jump leads test your battery

Step 2: Inspect the Starter Motor Wiring

If the engine won’t start using jump leads, the next step will be to check the wiring to the starter motor. To do this it is best to re-earth the engine by connecting a single jump lead between the battery negative terminal and the engine block.
**Ensure that your vehicle is a negative earth system** - this will be evident if the negative battery terminal has an earth strap connected to the bodywork or engine block.
After successfully re-earthing the starter motor try and start the engine. If this is successful it indicates a problem with the engine earth strap(s). In this case, check the wiring and connections of all earth straps and retest.

Step 3: Check the Thick Battery Positive Lead

If your engine still fails to start you need to check that the thick battery positive lead from your battery positive terminal is not loose, damaged or corroded. If you suspect a damaged battery lead then remove and clean, tighten or replace.

Ignition Switch Failure

In some rare cases ignition switch failure can cause a starter motor to fail.

Need a Replacement Starter Motor?

If our 3 step starter motor testing proved inconclusive, you may need a replacement starter motor. As always we recommend seeking expert advice. Give us a call today for guidance on 0845 564 2681. Alternatively visit the starter motor section of our store to find a replacement today.

Our testing guides should be used for guidance only. We advise you to seek expert advice from a qualified mechanic if you suspect a faulty engine part. Before attempting work on your car, firstly read our Safety Guide.