TIME BOMB?
Q: I have a '97 GMC Suburban two-wheel-drive barn-door model with the 5.7L V-8 and automatic transmission. I've lowered the truck with spindles, springs, and hangers. I'm running 18-inch rims and I've done some paint and body mods, but I've left the engine stock except for a K&N filter. I use the truck for daily driving and weekend boating.

My problem is a ticking noise that reminds me of a cartoon time bomb about to explode. I know it's not a bomb, but I'm still concerned. The noise is definitely coming from the engine compartment. I've had passengers comment on the noise, so it's not just me. I thought it might be a loud or defective fuel pump, but the noise seems loudest on the right side of the engine. I'm also pretty sure it isn't a problem with fuel injectors. I've had cars with noisy injectors, but this ticking doesn't sound like that.

The noise seems loudest in the morning when I first start the truck. The colder it is, the more noticeable the noise is. My Suburban runs fine, but now that I've become aware of the ticking, it's starting to drive me crazy. Have you heard of similar problems? Is there anything reasonable that I can do to cure the problem?

I have another less annoying problem. The rear barn doors are getting harder and harder to open. They seem much stiffer than before. I've had some short-term success with spraying WD-40 on the hinges, but no permanent improvement. The door gaps seem fine and the doors don't appear to sag. Is there an easy way to fix this problem? Thanks for your time and help.
Nolan Kerrigan, Cocoa Beach, Florida

A: Noises without a definitive source can be difficult to diagnose. Given your location, description, and the fact that the ticking is most noticeable when the truck is cold leads one to suspect the evaporative canister purge solenoid. The solenoid is mounted on the right side of the intake manifold, close to the throttle body. The action of the valve plunger hitting the port seat is what makes the ticking sound. Noise from the purge solenoid will be most noticeable when the engine is cold.

The solution is to get a new, improved solenoid (PN 1997277) that was designed to eliminate the ticking. Depending on the mileage on your truck, there is a chance that the solenoid replacement may be covered by your warranty. It's worth checking into.

This ticking noise problem with the evaporative canister purge solenoid is common in a great number of '97 and '98 GM light trucks. The vehicles affected include: Chevy C/K pickups and Suburbans, S-10 and Sonoma pickups, Blazers and Jimmys, and Astro minivans. Engines that may have this problem include: 4.3L V-6, 5.0L V-8, 5.7L V-8, and 7.4L big-block V-8. RPO codes are L35, LF6, L30, L31, and L29.

Your obstinate rear doors are a problem shared by many '92-'97 Suburbans with barn doors. People who live near saltwater or other corrosive elements tend to have the most problems. The hinges corrode, which makes them stiff. Lubrication will help, but the best solution is new hinge pins and bushings. Replacement is simple and you should be able to do it yourself.

Alternating Slippery Conditions
Q: The alternator on my '93 Ford Ranger pickup seems to vary in its effectiveness. Most of the time it charges fine, but other times, it doesn't seem to charge as it should. The engine is the 4.0L V-6 and the transmission is the automatic. The truck has two-wheel drive and a Traction-Lok differential.

The alternator charges fine on nice, sunny days, but when it's rainy or after we've had a lot of snow and it's melting, the alternator performs poorly. I had the alternator checked at my local parts store and the guys there said it was up to specs.

I checked the drivebelt tension and the belt condition. Both things seemed fine. Is there a reason the alternator would intermittently underperform? Could I have some type of short that doesn't show up when the alternator is on the parts store's test bench? The closest I can come to pinpointing the problem is that wet weather seems to be a factor. Does that suggest anything to you? I don't want to buy an unnecessary alternator, but I also don't want my battery to fail.

Another problem I have is noise and vibration in the rearend. This problem tends to happen after I've done quite a lot of freeway driving and then I go somewhere on surface roads with lots of curves or turns. The chattering-type noise is most noticeable when I make a sharp turn at relatively low speeds. If I make a U-turn, the noise is worst of all. Is this a sign that something's going out in the rearend? Is there something I can do besides not turn corners? Thank you.
Marc Richmond, Green Bay, Wisconsin

A: Your guess that the alternator problem is weather-related is probably correct. Other Ranger owners have experienced similar problems. The alternator is OK, but there can be too much moisture on the alternator drivebelt. Areas with lots of rain, snow, or potholes can make the problem worse. Melting slushy snow is probably the worst condition for this problem. All that splashing moisture is getting on the drivebelt. When the 'belt gets too wet, it can slip and cause the observed difference in alternator performance.

According to Ford's service bulletin TSB 94-18-8, the solution is a splash shield to better protect the drivebelt. Ask your Ford parts department for splash shield F37Z-16103A.

You said you checked the 'belt tension. That's something everyone should include in his or her preventive maintenance. The basic rule is that there should be about a 1/2 inch of deflection at the center point of the span between two pulleys. Individual trucks may have a specific deflection recommendation, but the 1/2-inch rule is a good starting point. There should be some deflection, because a too-tight 'belt can also be bad for the alternator.

Your rearend noise and vibration symptoms sound like Traction-Lok problems. Two possible problems are a lack of friction modifier in the lube or clutch packs that have been overshimmed. You can drain and change the rearend lube yourself. Be sure you get the right lube, or you'll be right back to the same old problem. If the new lube doesn't solve the problem, you'll need to have the clutch pack checked by a specialist. Other owners of '93 to '96 Rangers with the Traction-Lok differential have reported similar problems.