I recently tackled replacing the A\C Blower Motor on my wife's Nissan Rogue. It was not an easy job working under the dash, removing the pedal assembly, and removing the blower motor in an area where it's almost impossible to see. I completed the job, satisfied the fan was working, and proceeded to nurse my aching back.

A few days later, my wife noted the fan was making a lot of noise so she had to turn the fan off, which wasn't great since the weather was well below freezing. I racked my brain for what could have happened. Maybe the blower motor was faulty or had somehow become loose? I once again crawled under the dash and pulled out the blower motor to discover I left the packing foam inside the fan blade! Feeling defeated but at least glad it wasn't anything worse, I reassembled the fan, and it has worked great ever since. I let my wife know I messed up the first time. But at least the second time replacing the fan took less time. I know now to double check my work.

Chris in Missouri

Putting on a new timing belt or chain may seem anticlimactic after all the disassembly work needed to make the old belt or chain accessible. It is important to continue to sweat the details to make sure the crankshaft, camshaft(s), oil pump and/or balance shaft(s) gears are all aligned correctly. Otherwise, the engine will run badly or not at all and all that disassembly work will have to be done over again. Here are a few tips for making sure the new timing belt/chain, sprockets, pulleys and/or gears are all aligned.

   1. Get all the parts you need before you start the project. Look at any Timing Belt/Chain & Component Kits available under "Engine" for your vehicle in the RockAuto.com catalog. The kit will show the parts (idlers, tensioners, guides, sprockets, water pump...) needed to completely repair your specific engine.

   2. Also read the directions and have the right tools before you get started. Follow any installation and alignment instructions that come with the parts or are in the vehicle's repair manual (found under "Literature"). Check Youtube and relevant make/model forums for images and other info from people who did the same repair, but be cautious, even two engines of similar displacement built by the same manufacturer may have different timing belt/chain designs. Videos and forum threads sometimes trail off without any follow up to reveal installation mistakes.

The amount of effort needed to get the alignment right usually increases when more camshafts and other parts (oil pump, balance shaft) are driven by the belt/chain but that varies by engine. Some dual overhead cam (DOHC) engines have cams directly linked to each other with gears (Toyota...) and other DOHC engines have cams that are only linked by the timing belt/chain (Ford, Honda...).

Camshaft Alignment Tools

Some parts may have timing alignment marks cast into or painted onto them. Other designs may require Camshaft Alignment Tools or other specialized tools to lock parts in place during assembly. A special plate that keeps two camshafts aligned may seem like overkill or something that could be done with a scrap piece of wood, but some engines are extra finicky and need that precisely machined tool in place or the belt/chain will be too loose, too tight and/or one belt rib or chain link off.

   3. If you are doing preventative maintenance (belt/chain, guides, etc. are not broken) and the engine is running correctly, then the old parts can be used to help align the new parts. Add your own reference marks (using paint, tape...) to the old parts and surrounding engine components before removing anything. Copy the marks you make on old parts to the new parts (belts/chains, sprockets...). Using both the factory and your own reference marks is a great way to ensure that everything went back together correctly. Be generous adding marks and use multiple colors so it is easier to see things like which spots on a chain are supposed to line up with which spots on sprockets. Nothing is lost if some of your marks turn out to be unnecessary.

   4. Be sure to remove any tools (alignment plates, bolts, pins...), excess marking tape, etc. before deciding the job is done and finishing up by reinstalling parts such as valve or timing covers. Something like a nicely made steel camshaft alignment tool can easily look like it is part of the engine head. (Maybe put a note "Don't forget to take off the camshaft alignment tool." on top of the valve cover while it is still sitting on the workbench.)

   5. Installation instructions sometimes recommend slowly rotating the crankshaft by hand while the belt/chain is still visible to help verify that nothing is binding up and any timing marks stay aligned after a rotation or two.

Tom Taylor,
RockAuto.com

To read more of Tom's articles, click this link and choose from story titles on the Newsletter Archives page.