4 Mistakes to Avoid in Automotive Leak Testing

As the number of vehicles on the road continues to increase and society places more focus and emphasis on the environment, the importance of leak testing in the automotive industry skyrockets. In fact, when it comes to leak testing, the automotive industry could be the most important sector of them all. This is because, from the cylinder heads and fuel valves in internal combustion engines to the lithium ion batteries in electric vehicles or fuel cell in hydrogen vehicles, there are several hundred different components in just one vehicle that have to undergo this type of testing. And, because there are so many different elements, leak testing in this arena can become quite costly.

Between cost, safety concerns, and emissions regulations, it is imperative for leak testing reports to be as accurate as possible. Unfortunately, there are a number of different mistakes commonly made that can decrease accuracy significantly, threatening the safety and reputation of the part, and vehicle, being tested. Knowing about these common errors beforehand can help you recognize, and completely avoid them. 

1. Trusting the Bubble Test Method

While the bubble test method, which remains one of the cheapest forms of leak testing, is still quite common in practice, it is more unreliable than some would like to admit. The process involves simply creating a pressure differential on a package with the testing part inside and then submerging it into water to visually watch for a stream of bubbles. However, the process is obviously quite rudimentary, subject to operator error, and is quite time-consuming.

One of the biggest issues associated with the use of this testing method is that it looks for larger leaks while allowing smaller, but still detrimental, leaks slide under the radar. Not only is the operator required to pay close attention for bubbles during the test, but there is absolutely no room for calibration since test pieces must be discarded if bubbles are seen. This method is no longer viewed as sensitive or reliable as it once was, and should not be trusted alone.

2. Neglecting Maintenance and Testing Contaminated Parts

Keeping up with routine maintenance, and ensuring that your test system is running appropriately is crucial to successful leak testing in any industry. Preventative maintenance of your leak testing systems will ensure that your system is maintaining the right sensitivity, helping your organization avoid costly downtimes or negative ratings. Depending on the system you’re using, preventative maintenance can include guaranteeing the test system is leak-free itself, replacing worn seals, performing internal checks, and cleaning surfaces.

But, the testing system itself isn’t the only element in the equation, and just as a faulty testing system can lead to skewed results, testing a contaminated part may yield incorrect readings. Sometimes, product contamination is inevitable. From oil and grease, which make certain parts even useable, to dust particles, contamination is sometimes simply unavoidable. Heavy contamination, however, can lead to wrong readings and inaccurate results. Just as you should take the time to keep your testing system clean and running properly, the test part should be new, clean, and as uncontaminated as possible for the best test results.

3. Ignoring Crosswinds

As mentioned before, there are several different methods of leak testing to choose from, and it is vital that the operator understand each of these methods and how they work. In the sniffer leak test, for instance, a low-cost sniffer probe is used to detect the presence of gas and identify leaks. While this is generally a reliable testing method, operator error can lead to skewed test results. Poorly timed crosswinds, which are pretty common in manufacturing environments, can greatly lower test reliability.

Because blowing air can prevent the probe from detecting gas leaks by blowing the gas away from the probe itself, it is important to remain mindful that the test area is shielded from moving air. Enclose the work station entirely to keep your operators from worrying about winds caused by the ventilation system or passing forklifts.

 4. Ignoring Test Part Temperature

Automotive leak testing is quite sensitive and must be done in a highly controlled environment. Every aspect of the test conditions, from airflow to temperature, needs to be regulated and monitored to generate the best and most accurate results. Temperature is another serious factor that must be considered. Failing to do so could ruin the entire test.

When leak testing parts, like radiators and automotive engines, the temperature should always be considered because some leaks may not become apparent until the part is closer to operating temperature. In fact, when it comes to some parts of the engine, the test may not even be valid if not completed within the temperature range. When leak testing parts that may not be as temperature-sensitive, it’s important for the operator to be mindful of temperature compensation. If the part just came from a cool area, was just washed, or recently underwent welding, temperature variations during the test could cause pressure changes in the part, masking leaks, and causing them to be missed.

 Final Thoughts

In order for safety and compliance to remain a priority for manufacturers in the automotive industry, leak testing must be taken seriously. Today’s vehicles are made of hundreds of tiny parts, bits, and pieces, all of which are at risk for developing leaks. Leak testing is crucial to guaranteeing the integrity of these parts and maintaining the reputation of the manufacturer. This is why certain areas of the testing process, from method to airflow, should be properly managed and maintained.

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