I think you're going to have to enlist the help of someone who can listen to what's happening. If that "clank" is a single loud clunk, that can be due to worn solenoid contacts inside the starter. That's real common on the little silver Nippendenso starters. Repair involves replacing the contacts for about 20 bucks, but most people just replace the entire starter. That problem always starts out intermittent. At first you'll have to cycle the ignition switch two or three times before the engine will crank. As it gets worse over a few weeks or months it will take many more attempts before it will crank. If the symptom is the same but the problem started suddenly and is not intermittent, it can be due to a corroded battery cable or loose or dirty connections.
If you're hearing a ratcheting sound, sort of like a loud buzzing noise, the suspects are a bad battery or loose or dirty cable connections. The dome lights will typically stay bright but they'll flicker rapidly in time with that noise. You'll need a voltmeter to identify that. Start at the battery and measure the voltage. If you find 12.6 volts, the battery is good and fully charged. If you find closer to 12.0 volts, it is good but discharged. You'll need to charge the battery slowly for an hour, then continue with testing. If it cranks and starts, you likely have a charging problem.
If you find around 11.0 volts or less, the battery has a shorted cell and must be replaced.
You can find a digital voltmeter at Walmart, Radio Shack, Sears, or any hardware store, home improvement store, or auto parts store. Don't waste your money on an auto-ranging meter or other features you'll never use. If you have a Harbor Freight Tools store nearby, they have a perfectly fine meter for less than ten bucks. It often goes on sale for $2.99.
If the battery voltage is close to 12.6 volts, measure it again while a helper tries to crank the engine. If the voltage stays high, there are cable connection problems or those bad solenoid contacts. If the voltage gets drawn down to less than about 10 volts, suspect the battery. You need to start the testing right on the battery posts, not the cable clamps bolted to them. If the voltage remains high there, then, one at a time, move the probes to the cable clamps and measure again. You're looking for a place where there is a big change in voltage during the test. That is where to look for a bad connection. If that sounds confusing, I can send you to a web page that has drawings that might make more sense.
Monday, March 19th, 2012 AT 11:49 PM