The sunroof in my Pontiac Sunfire has beengetting fussy lately. Sometimes it initially won't close but finally does aftera few tries, and it's making some bizarre popping and scraping sounds. Withwinter coming up, I want to get it fixed. Can I do this myself?

You'd think sunroofs would be just asreliable as power windows, but turning a sliding panel on its side makes themechanics far more difficult. A sunroof doesn't just slide back and forth; itsmechanism must also tilt the panel up and down to accommodate the sliding andventing motions. So in addition to the electric motors and switches and slidesin windows, sunroofs have plenty of additional partswhich are typically theones that break. Popping and scraping noises are generally not happy sounds forcars to make; in a sunroof they indicate surfaces binding, drive gearsslipping, or, put plainly, that something mechanical isn't working correctly.It'll probably break for good when it's least convenient (and raining).

There are two approaches to repairing anailing sunroof: the first is to fix what you've got, the second is to replacethe whole megillah. All the greasy bits of sunroofs live between the roof sheetmetal and the headliner. Before you start pulling the car apart, find a placeto work inside or check the weather forecastbeing caught with a hole in theroof during a downpour wouldn't be fun. The first thing to try is removing theglass panel. If you can, tilt the sunroof panel to the "vent"position, which should give access to the screws holding the panel. Removethem, and with the sunroof glass off, you should gain access to the movingparts for an easy inspection. Look for cracked or stripped gears, a buildup ofdirt and debris, or anything else that looks like a problem. With the glasspanel still off, turn on the car and cycle the roof control through the open,close, and vent positions to identify problems.

In your case, it sounds like you might beable to get away with replacing the gear on the motor at the front of thesunroof, but without opening it up, it's impossible to know. If you do find andfix the problem, clean everything, then slather it with lithium or marinegrease for smooth future operation. If you find nothing, don't bother puttingthe sunroof back together because you're just going to end up removing it allanyway. Installing a new sunroof is a big jobyou'll have to take off theinterior trim around the door pillars as well as any overhead handles or domelights, then pull the headliner down, disconnect the sunroof wiring harness,and unbolt the whole mechanism. It's in one big rectangular piece called acassette, which should swap for the new piece without any fight. Be sure to doa function test before putting the interior back together; it may need a littlejiggle for a perfect alignment. To answer your final question, yes, you can dothis repair, but it's complicated enough that it may be worth the cost to havea mechanic do it.