On The Road

Perfect tool for the job

I really have a passion for the automotive field. I also have a tremendous love of all tools.

Anyone entering my shop would probably say that I have just about every automotive tool necessary, but they would be wrong. I still have a list a mile long.

Along with all of the tools we could not live without, there are some exciting new ones that have come to the forefront, including one of my most recent purchases – a digital borescope from Snap-on – the Snap-on BK8500.

A borescope is a small, articulating camera on the end of a long probe. It has a wireless screen and provides amazing pictures and live high-definition video. The original borescopes were tubes with an eye site on one end and a lens on the other. They were like upside-down periscopes. The technician would insert the tube into the cylinder bore and look for problems. With the old borescopes, we could see rough images and get a general picture of a valve or piston inside an engine. Now we can see amazing HD detail and live-action video.

Borescope to the rescue

Last month we had a new customer (and a reader of my column) bring in his 2006 Subaru Outback LL Bean H6 (6-cylinder) 3.0 liter. The customer had already taken his car to other shops and spent a large sum of money trying to solve an early-morning misfire.

The customer said he had persistently been getting a P0303 engine code – a misfire in cylinder No. 3. What is unusual about this failure is that we rarely see the 3.0 liter’s H6 misfire. The customer also said the other shops had replaced the engine control module (ECM), ignition coils, injectors, spark plugs and more.

If you are one of my regular readers, you know that I write a lot about Subaru misfires. Once we pulled the codes, we found an ECM P1571 reference incompatibility. This was concerning, because the customer had just had an ECM replaced. It is also extremely rare and expensive to replace ECMs. There were no other codes and no misfire codes.

We then checked all of the basics: the spark plug in cylinder No. 3 (compression was good), the power and ground to the No. 3 injector and the No. 3 coil. On top of that, we could not get the car to misfire.

On the second morning, I got into the car to drive it out of the garage. Immediately on start-up, the car misfired. So we checked for codes and no misfire code came up. We then used the new borescope. We figured that if we pulled the No. 3 spark plug and put the camera into the No. 3 cylinder and then ran the engine, we might see something. We prepared the car the night before and put the camera in place.

On the third morning, we fired the car up and looked at the screen. The head gasket, seen in the upper-right corner of the picture, had what looked like a river of coolant coming from it.

This was an enlightening moment – it was as if we had X-ray vision looking into the engine. The flood of coolant was causing the No. 3 cylinder to foul and misfire. As soon as the car warmed up, the head gasket swelled and cut off the coolant leak. As soon as the coolant stopped spewing, the engine ran well. So we found the problem: The head gasket needed to be replaced.

The customer decided to hold off on the repair, but at least now he knows what was causing the misfire. I’m really glad that our new borescope worked so well.

Matt Pataky owns Sunnyvale Foreign Car Service, 15 Pioneer Way, Mountain View. For more information, call 960-6988, email This email address is being protected from spambots. You need JavaScript enabled to view it. or visit sunnyvaleforeigncar.com.

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