Babying battery might not be worth it
Question: I am a very old man and use my car, a 1998 Lexus 300ES, once a week for a short run. I installed a disconnect switch on the negative side of the battery. Every time I come back to my garage, I dis-connect the battery. Does it make sense to do this? — Alex
Answer: It sounds like you are trying to be careful not to allow the battery to become discharged between trips, but it might end up being more trouble than it's worth. Since you aren't having problems starting, your short trips appear to be sufficient to replenish energy used during startup. Disconnecting and reconnecting the battery erases memory settings for the clock, radio and memory seats, as well as learned or adaptive values for engine management. Your emissions-readiness monitors also are erased, which could be inconvenient when testing is required. Some vehicles are fussy about running their diagnostic monitors, requiring several days or even weeks of driving before completing them. (They're required for emissions test compliance.)
If you were parking for perhaps three or four weeks at a time, I'd consider mounting a float/trickle charger under the hood and plugging it into an outlet at the front of the garage. Carefully mounting the charger cord in the grille could allow a tolerable “oops” situation, should you forget to disconnect before driving away.
Your short trips are of some concern, as you may not be bringing the engine up to temperature long enough to clean up your motor oil. A jaunt of a half-hour or longer, at least occasionally, would help with this as well as fully charge the battery.
Q: I have a 2008 F-150 with the 5.4-liter engine. The heater suddenly stopped blowing hot air. The temperature gauge starts at cold and after a few minutes goes to mid-scale normal. We have had subzero temps lately. Is there a water line from engine to heater that might have frozen? Any ideas? I am freezing.
— Randy Horvat
A: I'd start by checking the temperature of the two quarter-dollar-diameter heater hoses that lead from the engine to the truck cab. With the engine at operating temperature, both hoses should be fairly hot and close to the same temperature: within 6-17 degrees F. If one hose is noticeably warmer than the other, the heater core may be restricted. If neither hose is hot, the engine may not be reaching operating temperature or is low on coolant. If the hoses seem OK, the fault lies within the heater box in the instrument panel. Most modern vehicles use a temperature blend door to regulate ventilation temperature. When heating is desired, air is directed through the heater core. Air can be diverted around the heater core to keep it cold, or a blend of cool and hot can be made.
Your blend door is controlled by an electric servomotor. It's possible that the servomotor isn't functioning or the blend door is stuck or uncoupled. A check with a scan tool might yield diagnostic codes and door position information that will lead to an accurate diagnosis. Ford's pinpoint test H takes a technician through all these checks.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at email@example.com; he cannot make personal replies.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.