The Car Doctor Q&A: Fuel, air conditioner, engine and more (2024)

by: AAA Northeast (Sponsored Content)

Posted: Jun 20, 2024 / 02:12 PM EDT

Updated: Jun 20, 2024 / 02:12 PM EDT

Viewer-submitted questions for The Car Doctor:

Q: Two years ago, I replaced the fuel pump in my 2012 Ford F-150. Less than a minute after leaving the garage, the “Check Fuel Fill Inlet” light came on. I went back and was told “that happens sometimes; it’s not our fault.” I have tried cleaning the fuel inlet with WD-40 and bought a new gas cap, but the light stays on. I am guessing there is an air leak somewhere, but the truck runs fine, gas mileage is unaffected, and – other than that annoying light – I haven’t had any problems. Should I get this fixed or can I keep on truckin’?

A: I do think the light had to do with the fuel pump installation and a vapor line is leaking. You are correct that the car will run perfectly, and fuel economy will be normal. At this point you have two choices: have someone test the system, including the purge valve/solenoid (usually the issue in most cases when the tank has not been removed) and repair the issue, or “keep on truckin.” Keep in mind, however, that the check engine light is on because there is a vehicle emissions issue.

Q: I have a 2012 Ford Fusion with an air conditioner that will randomly start blowing hot air. It is inconsistent and arbitrary. I have done a little research into it and it seems the best advice is not to put it on full blast. I removed the blend door in so that in the summer it is incapable of blowing hot air. I’ve heard this is somewhat common. Have you experienced it with this vehicle?

A: It is possible that the system is a little low on charge and the evaporator is freezing up. The advice not to run the system on max will help eliminate that problem. Low refrigerant equals low pressure, which equals low temperature, which equals ice. The ice blocks the air flow. At this point – considering the car is 12 years old – you should test the system for proper pressure, check for leaks, and examine the clutch operation. It is always best to test first before replacing parts.

Q: I have a question I thought you might be able to help with. I have two teenage drivers in the house (one home from college for the summer, one high schooler), both of which will have full-time summer jobs. We are two parents working a mix of hybrid/in-office and, while we might be able to come up with a carpooling schedule, we could really use a 4th car for the summer months. Money is an issue; I’m not able to rent a car for months. Public transit is not an option where we live; neither is walking or biking. Is there any kind of peer-to-peer marketplaces out there for “borrowing” or anything else worth considering?

A: There is a company called Turo where you can rent cars from private hosts. Some people do this with an extra car, other more entrepreneurial folks have small fleets of used/older cars. Entering my zip code, I found a Nissan Versa and a Toyota Echo renting for $20 per day.

Q: I have a 2008 Chevy Cobalt with 80,000 miles. The factory alarm keeps going off every 30 to 40 minutes. Occasionally the alarm goes off when the lock button on the fob is pressed twice, which is supposed to set the alarm. I was told this could be due to a weak battery in the fob, but the same thing happens with both fobs. Any thoughts?

A: The most common issue is the hood switch, but here is something to check first. The first thing is to verify the system is working properly. Individually open and close each vehicle door, the trunk and the hood while observing the door ajar indicator/message. This message should accurately transition between the “door ajar” and “door closed” messages when each is opened and shut. If the messages aren’t doing this, the switch could be faulty.

Q: I have a 2017 GMC with a 3.6-liter engine and the check engine light came on. The repair shop told me the truck needs a thermostat, at a cost of almost $1,000. When I was a kid, I replaced the thermostat in my Chevy pickup for $10, so why is this so expensive?

A: In some GM vehicles, the thermostat is incorporated into the water outlet. So instead of needing a $20 thermostat, you need to replace a $250 water outlet. Additionally, the water outlet is under the intake manifold, which requires about 4 hours of labor. With labor in the $150-$250 per hour range, it’s easy to see how the repair costs climb to $1,000.

Q: I have a Volkswagen that kills the battery when not used for a couple of days. Now a dumb question: how do I check for a parasitic drain? When I open the door, all the systems come back to life. It’s not like I can crawl in through the window and start pulling fuses…I need to have the door open and there is no door switch to hold it closed.

A: You can trick the system into thinking the doors, hatch and hood are open by taking a screwdriver shaft to trip the latch mechanism. You just need to flip the latch in the other direction to close the doors and hood. Remember, the only dumb question is the one you didn’t ask.

If you have a car question, email the Car Doctor for a personal reply.jpaul@aaanortheast.com

If you’d like more information, head toAAA Northeast.