Q: I live in Minnesota and am a first-time owner of a vehicle with a CVT — continuously variable transmission. It does act differently at times compared with traditional transmissions. Lately our extreme cold weather causes the engine to run at higher RPM relative to the same speed in warmer weather. The condition goes away when the engine warms up. Does it hurt the CVT or engine to drive normally at temps below zero without a longer warm-up?
A: Having spent many years in cold climates, I've experienced a similar syndrome many times before, but not with an automobile. Snowmobiles utilize CVT transmissions with variable-diameter drive and driven pulleys and a reinforced V-belt. It is completely normal to experience higher engine RPM versus road speed when cold due to the "stiffness" of the lubricants and drivetrain components. In extreme temperatures, more power is required to "drive" all these components until reaching normal operating temperatures. While start-up operation in extreme cold is stressful on any machine, it is no more stressful for your CVT transmission than any other type of transmission.
Anything that raises temperatures of coolant, lubricants, driveline components and/or the battery prior to starting will reduce stress in extreme conditions.
Q: The headlamps on my 2002 Jeep Grand Cherokee are severely scratched and need replacing. I tried a headlight restoration kit but it did not do a good repair. Also, both hood and rear window lift struts are no longer functioning — all four struts need replacement. Are headlamps and lift struts do-it-yourself repairs or do you need an engineering degree to replace these items?
A: Not unless you drive an extremely expensive exotic car — then you'd need the degree to earn enough to afford the parts!
The lift/support struts for the hood and rear window are easy to replace. Prying up the small retaining clip on the ball socket on each end of the strut allows the strut to pop off its mount. If you're still hesitant, I'll bet your friendly auto parts store staff would install struts at no charge if you buy from them — just ask.
And before you give up on your headlights, make sure you've tried every option. Many dealerships and body shops offer headlight restoration service at roughly $25 per light — certainly worth a try considering the replacement cost for new composite headlight assemblies for your Jeep is about $350 each.
I've sanded the composite surface with very fine sandpaper — 600 grit or finer — then buffed the lens surface with automotive polish. If new replacement headlight assemblies are your only option, what have you got to lose?
Motoring Note — from Gary Sherman: "I have an addition to your answer about washing a car in cold weather. Immediately after I run my car through the car wash I open all the doors so they are on the first latch, turn on the heater/defroster full bore and head for home. This helps dry out the weatherstripping and locks. When I get the car home I leave the doors open in the garage at the first latch for several hours, then open and close them securely. If there is any ice it usually is broken up by the closing of the doors, trunk hatch, etc."
Thanks for sharing, but I can't condone driving home with the doors only partially latched. Also, with most newer vehicles you could actually leave the doors, hood and trunk open in the garage for as long as necessary to fully dry out. The "battery saver" feature typically turns off any lighting or accessories after a few minutes.
And as I said in that column, spraying or wiping door seals with aerosol silicone helps prevent freezing and sticking between washes.