Question:

There was a letter in your column recently about a low tire monitor light. I had a low tire light come on in my 2008 Toyota 4Runner. I went to the tire store, and they aired up my tires to recommended pressure, but the light stayed lit. I stopped by the dealer to ask how to determine which unit might be faulty. The service writer asked if the tire shop had checked the spare tire; I said no. He crawled under and put air in the spare and the light went off. I didn’t realize the spare had a low tire unit. — T.K., Colorado Springs

Answer:

Good point and one that I am happy to pass along. Most vehicles with full-size spare tires have sensors on them. Yeah, they were quite often overlooked as the source of warning lights glowing. Vehicles with mini spares or inflators instead of full-size spare tires don’t have this issue.

Question:

I have a 2009 Hyundai Azera Limited with about 83,000 miles. Last year, the TPMS warning light started flashing intermittently, but would eventually go off. Early this year, the dashboard started showing the “TPMS System Failure” warning at start, and the TPMS warning light glows permanently. I had it diagnosed a couple of months ago. They stated they need to replace all four TPMS sensors and recalibrate the system; their estimate for this was slightly over $1,400. This seems like a lot of money. Is this a justified cost? — J.F., Eden Prairie, Minn.

Answer:

Chances are the tire pressure monitoring system (TPMS) control module is the culprit. Call around for quotes to replace it and reprogram all four of the speed sensors. Keep in mind that one or more sensors could also be bad. The cost should be well under a grand to replace the module.

Question:

I have a 2013 F-150 3.5L Ecoboost engine. After looking into the source of a slight burning odor inside the truck cab, it has been determined the vacuum pump is leaking a small amount of oil and dripping onto the exhaust manifold. I was given a quote of $650 to replace the vacuum pump. I have not yet had the work done and I’m told the oil leak will not get worse, but I am not convinced. In spite of these issues, I like the truck but am considering cutting my losses and replacing it even though I now have an almost completely rebuilt engine with relatively low mileage. — T.S., Peru, Ill.

Answer:

Although minor now, it could get worse. I would replace the pump. Anything flammable, like oil, could catch fire, especially contacting the hot exhaust manifold. Replacing the pump, especially with a rebuilt unit, is a lot cheaper than replacing a truck that has become a cinder.

Question:

I own a 2018 RAV4 that has had a rising oil level since 15,000 miles. The dealer refuses to acknowledge there is a warranty problem. I have had it in many times and they tell me I don’t have a problem. I have owned cars for more than 50 years and have never had more oil on dipstick over time. How much trouble can this cause? — D.F., Tiffin, Iowa

Answer:

Unlike oily plants like palm trees and flax, the oil in your crankcase does not grow. The most likely source to increase the volume in the sump is gasoline. Bad piston rings, for instance, can allow gas to seep past. Check for the odor of gas when you pull out the dipstick next time.