I have a 2015 Nissan NV 200 van. The maintenance guide does not mention shock absorber replacement. Are the shocks lifetime of the vehicle? 

I am glad to see you reading the vehicle owner’s manual. Unfortunately, not every part in a vehicle has a specific replacement interval. Shock absorbers, like ball joints, radiator hoses and drive belts, require periodic inspection. Shock absorbers can last as little as 20,000 miles and may even last the life of the vehicle, depending on how and where the vehicle is driven. Periodically the shocks should be inspected for oil/seal leaks. If there is oil on the shock absorber it needs replacement. The old standard test of bouncing a car still is a good test. Go to one corner of your van and push down hard. When the van rebounds it should only bounce once and then settle down. If it continues to bounce, it is time for new shocks. If it is time for new shocks, they should always be replaced in pairs. 

I have a question regarding my 1968 Pontiac GTO that I have owned for almost 20 years. It’s been restored and is a low mileage California born and bred car. My problem is that the car runs smoothly at normal in town speeds (up to 60 MPH but on the freeway, once you reach 68-70 mph, the car tends to shake as if the wheels are out of balance. I recently installed a set of expensive Firestone redline wide oval radial tires purchased from Coker Tire. When they were first installed by a local shop, due to the vibration, I felt that they were not balanced properly so I had a different shop rebalance them.  Unfortunately, there was no change. I have disc brakes up front and drums in the rear. Both were replaced, including the drums, within the last 1000 miles. Most front-end components and suspension parts were also replaced. Could you suggest what the next step I should take to diagnose this issue. The issue only seems to be noticeable at high speeds. A friend of mine suggested that the drive shaft could be out of balance. I’m anxious to have this car run as good as it looks.

A.

First off, I don’t believe it is a driveshaft balance issue. If it were, you would feel the vibration in the body of the car much more than the steering wheel. Back in the 60s, 70s and even 80s we would use an on-the-car wheel balancer. These balancers would not just balance the wheels and tires but the hubs, rotors and drums. With a little investigating you may find a shop with one of these balancers.  The other possibility is that the tires, wheels and hubs need to be better matched to each other. Every tire, wheel and hub have a high and low spot. If the high spot of the wheel is mounted on the high spot of the hub, even if the wheel and tire is perfectly balanced you can get a vibration. At this point it will take some time with a dial indicator and runout gauge to get everything as close to perfect as mechanically possible. 

I have a 2022 Chevy Bolt EUV.  I have a question about charging the system to a maximum mileage. When I first got the car, it was charging up 296 miles, now it charges only up 241. Would the cold weather have any effect on how much it charges? 

Certainly temperature, accessory use and climate control will all have an effect on mileage/range of an electric car. AAA testing of electric cars has shown that in very cold weather, range can be reduced by as much as 30 percent and in very hot weather range can be reduced by 15 percent. Looking at the specification of the 2022 Bolt, the 241 mile range is still higher than the advertised number. General Motors did issue a recall on some Bolt models due to a possible battery fire. GM has advised owners to set the maximum charge at 90 percent and avoid depleting the battery to less than 70 miles of range. They also recommend charging more frequently and not charging the battery indoors at night. I read that GM does have a fix for the battery issue, but like everyone else they are waiting for parts. 

With new and used car prices going up and limited inventory due to chip shortages, have you noticed increase collectible car prices. I read Hemmings Motor news and some other old car publications, and it seems as if these cars are also getting more expensive. 

Collector car prices can be very cyclical. There have been fortunes gained and lost buying a selling some collector cars. Prices are determined by several factors: condition, rarity and market demand. Value will always be determined by how much a buyer is willing to pay. There are tiers of the buying public that have plenty of available disposable income, time and storage space that can drive prices up on some popular vehicles.