Piston Slap: The Panther That Cried…Wolf?

TTAC commentator confused1096 writes:

Sajeev,

Writing to you again after a hiatus of a three years. You and various commentators helped with my not so dearly departed Windstar (died of a blown transmission a couple of months after article). Now hoping I can get some input on a decent car.

Fast forward three years later. I sold a nice Nissan 300zx and bought a human sized car in March. I’m the proud owner of a nearly showroom looking ’98 Grand Marquis LS. The car was purchased with 198k on the clock and 10 years of maintenance records. It now has 211,000 miles. I’ve updated all routine maintenance, replaced brakes & rotors, rear shocks, etc. Really the only thing the car needs at the moment are front shocks (soon) and I plan to have the seats recovered early next year. Also plan on adding dual exhaust and a few other minor tweaks next year. This is my second Panther platform car, so I’m reasonably familiar with the common issues.

Now to the problem: Ever since I purchased it I’ve had a charge light that will illuminate on the dash intermittently. The alternator tests good, as does the battery. The car has no codes in memory and I’ve checked all the connections for battery, starter, and alternator. All are clean and secure. My regular mechanic thinks the diode in the alternator is going out. I hate to replace a pricey alternator on a maybe. Besides, shouldn’t the various part store tests have picked it up if that were the issue? I don’t want to have a boy who cried wolf attitude over an important warning system either.

Sajeev answers:

Don’t worry bro-ham! Rarely is it crying wolf when we’re talkin’ about an older vehicle’s charging system at this mileage.

Especially with 1980s-1990s Ford alternators of the poorly rebuilt variety. And from a corroded wire you will never see upon casual inspection to a failing lead plate in the battery, there are too many fail points to easily neglect, and wind up stranded in the middle of nowhere.

Your mechanic is probably right. Or it might be the regulator on the alternator, which is pretty cheap and easy to replace. Your best bet is to get a volt meter that plugs into your cigarette lighter to see the actual numbers. It’s cheap insurance, I’ve used one for almost a decade and I love it. Mine isn’t as pretty as the one below, but its paid for itself many, many times over. (which is an indirect slam against the quality of remanufactured alternators)

By the way, any parts store can test the charging system for free, with a fancy machine that is quite accurate.

Honestly, it sounds like you need a new (high quality rebuilt) alternator. One that is 100% all new, but still has a lifetime warranty. The new platinum alternators available at some parts stores will suffice. I’ve had good luck with local alternator rebuild shops and the nice folks at PA Performance. So you have options.

And now, in a poorly transitioned segue, here’s more fan mail on the same subject: Panther Love.

Stefan writes:

Oh Sajeev (note correct spelling) (WOOT, SM), I have no tricky questions for you at all today. I just wanted to thank you for your excellent and entertaining Fat Panther wisdom in many recent articles at TTAC. I took it all to heart and recently purchased this mint condition triple black ’97 Town Car (see picture attached) for $3,900.00 from a Chicago dealership. Most of the other vehicles on the lot were used police cars; regular Panthers. The Town Car already had the correct Replacement Aluminum Intake Manifold installed. New rotors & pads plus a set of Cooper Sigma Shadow Whitewalls and I am set to go for another 50,000-miles in great comfort and economy at 27 mpg.

The car had 84,000 miles on the odometer when I bought it. I’ll write you again when I get to 300,000 or so…..again, many thanks!

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.