Viewer-submitted questions for The Car Doctor:

Q: When the new bumper laws came into effect in the late 1970s (I think), I remember they required that front bumpers should be able to withstand a collision up to 5 mph with minimal or no damage. Today’s cars don’t seem to be able to withstand any sort of contact without damage. The first one that comes to mind is the Ford Fusion, although there are many others. Is this law still in effect? It doesn’t seem to be followed.

A: The rules have changed and not necessarily for the better. Cars now only have to meet a 2.5 mph test. Once I got through the legalese, it appears the regulations (Title 49 Subtitle B Chapter V Part 581) exempt trucks (including SUVs). These vehicles are, of course, still crash tested, but the idea of no or minimal damage at low speeds seems to have gone the way of the Bricklin SV-1 (

Q: This year I purchased a Bullitt Ford Mustang, and it is in very good shape. What are your thoughts on car covers? I’m going to rent storage space, but should I still cover the car? Is there a brand you have used?

A: The Ford Bullitt Mustang is iconic and deserves a good car cover. When parking outside, a good multilayer, breathable, waterproof cover will keep the car clean. When parked inside, you can use the same cover, or you could go with a lighter weight indoor cover. I don’t own a car as nice as your Mustang, but I have VW Beetle that I keep under a carport in Florida. I have been using covers made by Empire ( and – with the exception of 150 MPH winds from Hurricane Ian – they have held up well over the years.

Q: I am looking to buy my neighbor’s 2011 Volkswagen convertible. It runs great, I love the dash vase, and it looks great except for the top, which has a tear in the corner. Can it be fixed?

A: You could try patching the top with the same type of patch that you would use for a canvas tent. These convertible tops last from 5-10 years, so it may be getting close to the end of its useful life. One word of caution is to look carefully at the rear window. Over time the top shrinks and puts pressure on the glue that holds the window in place, and the window falls out. A replacement top, depending on the quality, is in the $3000-$4000 range.

Q: I have a 2016 Chevrolet Cruze and it is burning oil and smoking. My local shop looked at it and thinks the engine is shot. Could that be right? Other than the oil smoke, the car runs well.

A: There was an issue with some of these 1.4-liter turbo-charged engines in that a piston ring land (grove) would crack. The telltale sign was leaking oil or drawing vacuum at idle through the PCV external port. The PCV port is part of the camshaft cover. You might also hear whistling noise.  The repair is extensive, because in most cases the pistons, connecting rods and bearings will need replacement.

Q: I have a 2013 Mercedes Benz E-350, a good car with its share of quirks. Recently the gas gauge was not reading correctly. I took it to my local shop, and they replaced the sensor and the fuel pump but it still isn’t right. Any ideas?

A: Mercedes uses a primary and secondary fuel pump and sending unit. This is due to the shape of the tank and how it fits around the driveshaft. Your next step should be to check the other fuel pump. This is fairly easy to do since you only have to remove the rear seat (not the fuel tank) to get access to the sender/pumps.

Q: I’m a bit of an old-timer and generally replace my vehicle’s engine oil every 3,000 miles (3-4 times per year). You (and others) now recommend longer oil changes. What about filters? I typically use a Fram or other name brand filter, but are these okay for the longer intervals? What do you use in your own cars?

A: Whan I can, I tend to use the factory filter. If that isn’t available, I have been happy with WIX. One of our readers reminded me that NAPA stores sell a premium filter designed for longer oil changes, the NAPA Platinum filter. Also, AAA members get a discount at NAPA stores.

Q: I was killing time on TikTok the other day and saw a video of a woman with the same car as mine (Honda CR-V) who only uses premium fuel. She said her car is so much faster now and worth the extra money. Have you seen the video and is this true?

A: Well, you made me join one more social platform. I did find the TikTok video and although she seems happy to spend the extra money, all she is doing is spending extra money. Most vehicles – even some turbo-charged vehicles – are designed to run on 87 octane fuel. Recently AAA tested a variety of cars, even those that recommended (not required) premium fuel. The tests were performed on an EPA-certified dynamometer, and we found there was no benefit to using higher octane fuel in an engine that doesn’t require it.

Q: I’m having an issue with my 2006 Mercedes Benz c230. When I turn it on, warning lights indicate the coolant and window washer fluids are low, but they are full. The battery on my key fob had to be changed, because it would not turn the car on or unlock the doors. Yesterday, the car would not start; the engine would turn, but the car shook and then died out. The tow truck driver said the issue was electrical. What can be the potential error that I can mention to a mechanic so they can focus on that first?

A: The coolant level indicator switch and windshield washer fluid level indicator switch are connected in series and are read by the front SAM control unit with fuse and relay module. The SAM (signal acquisition module) is basically like a hub/router in your house, and various circuits run through it. These modules are usually pretty good but can fail due to corrosion, which can also affect the keyless start and perhaps the overall running. I would explain to your shop what you did with me, and suggest they start by looking at connections to this module. 

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If you’d like more information, head to AAA Northeast.