In the last article regarding automotive repair in Boston, we continued the discussion of making a hybrid vehicle safe to work on. If you are a Boston auto repair facility, be sure to revisit the last article by clicking here knotmove.com/diy-mechanic-in-boston. As a Boston area automotive repair facility you should by now be seeing hybrid customrs coming through your doors. Be sure to let them know that you can provide full service to them whether they are just visiting Boston, or living here! If you are reading this as an interested DIY’er living in the Boston area then know that there are a number of things that you can do yourself in way of servicing and maintaining a hybrid vehicle. Always start with attending a course on hybrid service. Look for one appearing soon in the Boston area.
As stated in the last article I will continue the discussion on safety. Here is a quick reminder of what we’ve covered so far:
- The biggest safety challenge with hybrids is the fact that they may start at any time when in ‘ready’ or ‘auto-stop’ mode.
- Be sure hybrid system is OFF and safe before performing any service, maintenance, or repair.
- Hybrids can contain up to 300v DC. They must be ‘safed down’ before working on the high voltage system.
- Always follow the manufacturer’s safety procedures.
- Disconnect the auxiliary battery to begin the safing procedure.
- Wear linesman’s gloves when removing the service plug or when handling HV components.
Along with all the usual safety concerns present while working on automobiles there are a few more basic safety precautions that are worth mentioning. Be sure to always wear your safety glasses and hearing protection when working around batteries and pneumatic tools, as well as ensure that a class ‘C’ fire extinguisher is present in the shop. Safety is a challenge because we never know just when something is going to happen, and as such must be prepared for the possibility all of the time. This has never been more true than with hybrid vehicles!
Many hybrid vehicles, if not all, utilize some form of electrically operated power steering systems. These systems generally work on voltages of 12v to 42v dc. Caution should be exercised around the higher voltage systems as they can pose a potential electrical hazard. Electric power steering systems can be disabled by removing their power source either through safing the system down as you would for the high voltage system, or by following the manufacturer’s suggestion of removing the appropriate fuse or relay.
A hazard that can be found specifically on the Toyota Prius is the presence of what I call the “hot water bottle”. This coolant heat storage tank is present on the Prius to provide hot coolant to the cylinder head prior to engine start-up in an effort to reduce cold start emissions. The challenge with this system is that it is designed to store engine coolant at a temperature of 176 degrees for up to three days! Many a technician has been surprised by extremely hot coolant when opening up the system after it has sat in the lot undisturbed for a couple of days. The coolant tank is positioned in the left front fender area where it is susceptible to impact. There is a high likelihood that if you intend on servicing hybrids, you will come across the need to replace this coolant tank. There are also TSB’s in the marketplace calling for the replacement of certain components of this system. Coolant drains are provided on the system for easy removal of the hot coolant – you just have to remember that the coolant may be hot before handling it!
A final word of caution is in regards to the electrolyte used in the nickel-metal-hydride batteries found in today’s hybrids. This electrolyte is a alkali, rather than the acid that we’re used to in batteries, however it is just as hazardous. It sits on the pH scale down in the area of drain cleaner. It is highly unlikely that you will come in contact with it, but if you do it can be neutralized with boric acid (available at most drug stores) or with vinegar. I encourage shops who intend to work on hybrids (especially collision repair shops who have a higher liklihood of coming into contact with the chemical) to keep a bottle of vinegar with the first aid kit on the remote chance that someone does come into contact with the electrolyte.
In the next article we’ll discuss how the high voltage electrical system protects itself, and thus how it protects you from unintended electrocution! This will be important to know for those times when you have a DTC for “short circuit in high voltage circuit” or a no run condition that you are having trouble diagnosing. Until next time, be sure to sign up and follow this feed to get the latest information related to Boston auto repair!
You can also visit www.intelligentmechanic.com to find the latest in technical training courses related to hybrid vehicles. As always, feel free to contact me with any questions or comments!