A tough EVAP leak
Sometimes EVAP leaks are close to impossible to find, especially when the leak is in the canister. Obviously when we are working on any small leak EVAP problem, we know it’s going to be difficult to locate. Our first line of defense is to use our Smoke Wizard smoke machine, connected to a CO2 supply. I have used CO2 with my smoke machine for years and for good reason. First, using shop air can cause potentially explosive gas fumes in the system and poses a safety threat to my techs. Second, if smoke is not readily visible, I can use my 5-gas analyzer to sniff out the CO2, saving my techs time.
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Since we now have the ATS BullsEye Leak Detection system, we no longer have to fire up the gas analyzer to locate CO2 leaking from the EVAP system. The ATS system uses CO2 to help techs find leaks in a variety of applications, and includes a CO2 leak detector similar to the A/C “sniffers” you’re used to. It is very accurate and easy to use, so we fired ours up and went looking.
As you can see from the picture (Figure 4), there was no smoke visible at the charcoal canister, but the BullsEye leak detector told a different story and pinpointed a canister leak. I have noticed over the years of diagnosing EVAP system problems that leaks at either the charcoal canister or the gas tank are the more difficult ones to find. With the use of CO2 and a tool that can detect CO2, I am able to find the leak easier. Our next step was to spray the BullsEye foam to confirm the exact location of the EVAP leak. Once the foam was sprayed on the canister (Figure 5), we were able to confirm without a doubt that the canister was leaking. We called the Nissan dealer and ordered a new canister, installed it and retested the system. Since the vehicle owner was leaving the vehicle for a few days with us, we were able to road test it cold a few times to confirm the repair. The vehicle was now ready to return to the owner with the EVAP system problem resolved.
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In our industry there are always new tools that come out, some good and some not so good, all designed to make our job easier. Using the ATS BullsEye leak detection system has really been a big time saver in locating not only tough EVAP leaks, but also in helping my techs find elusive leaks in air conditioning systems, head gaskets and tough tire leaks. Take a look at (Figure 6) this A/C leak we had on a Honda that could not be located by the A/C sniffer (that conforms to the new J2970 standard) or by the use of A/C dye and a UV light. Another difficult case my guys faced was a 2004 Audi 3.0L V6 with a vehicle owner concern of antifreeze usage. The first thing they did was to perform the usual visual inspection and cooling system pressure test. The results of the visual and pressure test did not provide us with any test results that were conclusive. Our next step was to perform a dye block test that did not result in any color change of the dye in the tube. Since all three tests had failed to indicate any problem, I told my techs that we needed to check the coolant reservoir bottle with the BullsEye leak detector. As you can see from the picture (Figure 7), the detector confirmed the coolant leak problem. Would we have been able to find this problem some other way? Sure, but having the right tools and using them the right way just makes finding the more difficult problems easier – and that makes our job easier!