April Auto Tech Update

School keeps rolling, five days a week for 3 hours each morning at York Technical College. The Advanced Diagnosis Class is covering a lot of different systems on the cars in the shop, so here's a bit of what's been going on lately. I've got four more weeks of diagnosis until the summer break. 

Our instructor is working with one of my classmates, using a bore scope to look inside the cylinders on this Cadillac. The car had a small coolant leak, so we removed the upper intake to look around. Then we pressurized the coolant system to see where the leak was coming from. Looking inside the cylinders was just a good check "while you're in there" because this car had direct injection, which leads to carbon build up, so that's what they are checking. This 2009 or so Cadillac didn't have too much build up. If it did, one way to clean it out is by blasting it out with walnut shells. Really. The carbon builds up with direct injection because the gas is being sent straight into the combustion chamber, and not the air intake where the gas would be cleaning the valves as it is sprayed towards the chamber. 

This kit should have everything you need to do a coolant pressure test. The various sized caps fit all kinds of radiator caps and coolant tanks. Then you use a hand pump (not shown) to pressurize the system. From there you can check that the system is holding pressure. If it's not holding pressure, then you can look for the leak. 

A 2006 Honda Accord on the lift, let's get to work. Plus, I thought it was a cool photo with the legs sticking out under the car, and one student in the background. Yeah, we're pretty artsy in composing our photos in Auto Tech class!

Replace the serpentine belt. Just to do this one by the book, I looked it up in ProDemand, our on-line resource. The instructions were literally as simple as "move the belt tensioner, remove belt, and install new belt." Dang, I could have written that! I might have used the traditional "assembly is the opposite of disassembly" too!

Here is an older Chevrolet Tahoe that is having some transmission work done. The transmission fluid pan has been removed, so we're looking up at the transmission filter (red arrow.) The entire piece of darker metal with the cut-out oval for the filter paper just pops in and out of the valve body. All of this "stuff" is swimming in transmission fluid, including those wires on the right. The other cool thing in this shot is the little red dots of fluid that are hanging on. At least I hope it's transmission fluid and not the red ANTI-MATER that Mr. Spock had to deal with in that one Star Trek movie!

Still on the Tahoe, here's looking a little higher at the rear of the transmission. The rear shaft is up there in the empty part, and would connect to the rear drive shaft. 

One more shot from the Cadillac. Before we tracked down the coolant leak, we drained the coolant from the radiator. I'd like to say THANK YOU to the GM engineers that made our job easy for a change. The red arrow is pointing to an expertly placed drain hole where ALL the coolant dripped out from the radiator. The fluid did NOT go all over the place, did NOT drip onto the sub-frame, and did NOT turn into a big mess. Imagine that! 
Happy ending, once we found the leak we replaced a gasket and an O ring, put the coolant back in, and the owner reports no problems!