Q: I just read one of your recent columns and wonder if you might be able to help me figure out what's wrong with my 2005 Saturn Ion. The car only has 48,000 miles on it and, for the past six months or so, has been making a knocking noise that sounds as though something's moving around in the trunk. It starts upon startup and continues for the first 10 miles or so of driving.
The car, of course, didn't make any of its usual noise when I took it in to a dealership or when I took it to a local garage, so neither was able to help. I'm thinking about taking it to AAA to see if they can diagnose the problem.
Any suggestions?
_Doreen S.
A: Noises are really difficult to solve without in-person inspection, but I'll give it a try.
Is this a one-time sound or one that repeats?
It seems we can rule out it being a long-forgotten can of dog food rolling around in the trunk, as you've surely checked, and the noise goes away after driving a bit, right?
If your Ion is the quad coupe version, a creaking or popping noise coming from behind the driver or passenger may be the result of one or both of the rear access door lower strikers rubbing on the door structure, as described in a Saturn service bulletin (06-08-64-015). Evidence of this could include shiny spots left behind. If this is the issue, a simple adjustment ought to do the trick.
If this doesn't help, I would venture that the cause might be an out-of-alignment exhaust system hanger or possibly a deteriorated rear suspension bushing.
It's a bit odd the noise disappears as you drive. Perhaps this is due to warming by friction. Is there a chance you could record the sound with your phone so a technician can get a better idea of what you're after?
Q: I'm shopping for tires for my Yukon XL 1500 and am torn between using the same P265-70-17 tires I'm currently using or going for some LT tires with an E rating. I pack quite a bit of luggage and tow a Mastercraft boat during the summer.
_Anthony R.
A: I went through this exact same dilemma several years back and can't wait for the LT (light truck load range E) tires on my Tahoe to wear out and be gone! The added tire stiffness and higher inflation pressure can make for a bone-rattling ride and loss of traction on a washboard surface. The 113-load index found in most tires of the size you mentioned is more than adequate for what you're doing. Be sure to keep them properly inflated to the door placard specification.
Q: My brother keeps bugging me to try putting some Rain-X on my windshield. He says I'll see better in the rain. What is this stuff? Is it worth trying?
_Alison B.
A: I give two big thumbs up to both Rain-X and Aquapel.
Both of these products are hydrophobic, meaning they repel water. One is a silicone polymer, and the other is a fluorinated compound.
Applied to a clean, dry windshield in mild-to-warm weather, both do an amazing job getting water to bead up into small slippery droplets that fly off the windshield above speeds of about 40 mph, markedly enhancing visibility. Neither is touted as a replacement for traditional wipers but, with one of the products applied, you may find you'll use your wipers less and they'll work better.
Aquapel is touted as lasting much longer than silicone-based products.
I'd welcome reader feedback on this one. So, folks, which do you like best?
