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In theory, every major component in a vehicle is thoroughly tested under severe conditions before entering production, but these tests are accelerate tests that try to duplicate many years in-service. So they are not perfect tests. The net effect is that the first generation of any new engine or transmission (the most complicated powertrain components) will tend to be less reliable and durable than subsequent versions.
With CVT’s, running at high power levels is stressful because it puts more heat into the friction surfaces and the special CVT oil, so I would certainly expect any CVT to last longer if it is driven easily than aggressively. Every CVT transmission has a maximum torque limit.
The main reason for Nissan CVT failures is that when introduced, they were relatively new technology. CVt’s have been continually developed since the first generation were put in production, and the newer the model year, the more reliable they are.
The reason why many Nissan CVt’s feel like there is a lack of torque (I think you really mean acceleration) is that they are calibrated for best fuel economy, and that means keeping the engine rev’s as low as possible for current speed and load. The other reason is that most of the Nissan’s are relatively low Power/weight vehicles, so in order to get a good level of acceleration, the transmission has to shift ratio to one that lets the engine get into the high power region. Remember that performance is proportional to Power/weight, not Torque!
If you physically can not turn the key in the ignition it is likely due to the steering column interlock. This is a feature designed to prevent vehicle theft by preventing a thief from being able to steer the car even if the ignition is “hot-wired”. This can happen from either a worn or improperly made key (like a duplicate key). More common is that you can get around this by simply moving the steering wheel back a forth a little bit while trying to turn the key. If this works, the problem is just the friction in the steering column interlock due to a little bit of load on the steering wheel. It should not take much pressure on the steering wheel to allow you to turn the key.
As engine oil approaches and goes beyond its normal service life several things happen that make it unsuitable for the engine:
1) The viscosity (oil thickness) changes. Continual exposure to heat tends to thicken the oil and it eventually becomes out-of-spec for your engine. this can increase wear in the engine
2) The detergents that are in the oil get depleted and the things that contaminate the oil continually (like soot) build-up; but the worst problem is that the detergents that are supposed to prevent sludge formation in crankcase stop working. The effect is that the oil starts turning into a grease-like product that will not flow to your bearings
3) The oil becomes corrosive, because the anti-corrosive additives wear out. This can lead to severe wear
4) In cold weather, especially with many short trips, the oil will become diluted with raw fuel and liquid water. This really degrades the lubricant properties of the oil.As to how long you can go with old oil, generally 7 months or 7500 miles, but the only correct answer is to read your car’s owner’s manual and find the answer in the maintenance section
The basic answer is Power/Weight ratio correlates to vehicle performance
The energy used to run the compressor in a turbocharger comes partly from the wasted exhaust energy (part comes from the exhaust pumping work), so the energy needed for boosting is partly free. The turbo does create extra back-pressure, so that does have penalties (parasitic loss and worse knock resistance at high power). The energy used to run the compressor in a Supercharger comes 100% from the crankshaft, so it is all parasitic loss and all of it contributes to higher cylinder loading and worse knock resistance. The net result is that turbochargers can provide more boost more efficiently than Superchargers.
There are 2 things that can be bad about too frequent oil changes:
1) If you don’t manually refill the new oil filter before installing it, the first startup after the oil change is with an empty filter and that means the engine will run without oil to all of the bearings for a few extra seconds while the filter fills up and the air in the filter gets pushed through the oil passages. Won’t kill your engine but something to be avoided or minimized in the interest of long engine life.2) I did not believe this until I saw this with my own eyes, but under normal service, an engine can look beautiful inside after 250,000 miles with just 7000 mile oil change intervals. Bearing wear, piston ring, piston skirts all looking pretty good.
I know many European drivers who rarely change oil more frequently than every 7,000 miles (some even 10,000) based on the vehicle maintenance minder, and are past 200,000 miles. So unless you are driving severe conditions, 3000 mile oil change intervals are just a waste.The best answer is to read the Maintenance section of your owner’s manual for the answer. They will usually list a mileage and time for change. The more general answer is; if you are using the old coolant formulation (usually green) that contains Silicates as the the anti-corrosive technology, you should not leave it in longer than 4 years. If you are using the newer Organic Acid Technology (OAT) coolants (usually orange or red), they are truly good for a 10-year stint.
The best way to compare fuel economy is the highway fuel economy number. It will correlate to real-world highway driving pretty well. If you want to get another good comparison measure, compare the curb weight of the vehicles you are considering. The lighter vehicle can be expected to use less fuel, handle better, and be easier on tires and brakes. Weight is the enemy of everything a vehicle must do: accelerate, brake, turn.
Just drive but take it easy with acceleration until the coolant gets warm (usually 5 minutes). If you are driving a manual transmission, try to keep the rpm below 3000 rpm until the coolant is at normal operating temp.
Dave
Every high voltage electric line and connector in a high voltage hybrid is bright orange to warn you. All of the full-Hybrid cars from GM, Ford, Hyundai, Toyota, Honda, and VW/Audi have battery high-voltage systems over 200 volts.
These high voltage wires and connectors are high quality and robust and shouldn’t be a hazard by themselves. If you do have to work on any of the high voltage components, the first thing you do is disconnect the big orange connector at the battery pack and this de-energizes the rest of the system. I would not recommend anyone work on a hybrid repair project without first reading and understanding the factory shop manual. The factories have special training for the technicians in their dealerships for working with the high-voltage systems.
Dave
No, there are basically 3 types of full-hybrids. The Toyota system is known as Power-Split where the “transmission” contains 2 electric motors (that are also operable as generators) that are connected to each other and the gasoline engine’s output by differential gears. This transmission has not clutches or shifting mechanisms. All of the variability in overall gear ratio between the engine and the wheels is controlled by the power controller that varies what each electric motor/generator does. This system also controls whether the the electric motors add power to the output of the gasoline engine or take power to charge the batteries.
The Hyundai and VW/Audi systems are the popular “P2” systems which are simply adding a large electric motor between the engine and the gearbox. This motor is in place of the engine flywheel and can be de-clutched from either the engine (to drive the car electrically) or from the engine (to regeneratively charge the batteries on deceleration.
The Honda system is unique. The transmission has an electric generator that is connected to the gasoline engine a motor/generator that is connected to the transmission output. At low to moderate speeds, only the output electric motor drives the car and the power comes from the battery. The battery can be charged by the other generator or form the motor generator on decels. In this mode the car is a series hybrid; no direct connection between the engine and the drive axles. Above roughly 40 MPH, their is a clutch that can lock-up and connect the engine directly to the final drive with an overall gear ratio equivalent to top-gear. In this mode the wheels can be driven by any combination of engine power and electric power. Here is a schematic: https://www.caranddriver.com/features/a15114066/explaining-the-honda-accords-shrewdly-designed-new-hybrid-system-tech-dept/
Yes, if your new car has the feature to calculate the oil change intervals, this is a better measure of when to change your oil than just miles driven or time since last oil change. On a modern Mazda, this would be the Maintenance Monitor, and could be set to “Flexible”. The true oil life is a function of how many hours the engine has been running and the temperature history of the oil. A good oil life system could have you change your oil in as little as 1500 miles if you do nothing but short trips in a cold climate, or more than 10,000 miles if you do mostly highway driving without getting stuck in traffic.
