My SL gives a loud tapping noise when I tried to start it yesterday. Sounds like a solenoid, but louder than usual. Lights are bright. I want to turn the engine over slightly to see if the starter will engage then. What is the size of the central nut on the crankshaft pulley?. Dont think I have one that fits.Any other ideas would be appreciated.

Well, that sounds like a bad battery or dirty terminals. I've seen cars do exactly what you describe and still have bright lights. Someone with more knowledge on the subject than me will have to comment because I don't know if the bendix needs to extend for the starter to work (GM type), or if it extends when the starter is energized like a Ford. If it's the GM type, it could be a bad solenoid but the stater...

Never mind, I went to my Alldata acount and it shows a starter like a GM one that has a solenoid on the starter so it could be bad solenoid contacts since it sounds like it is clicking.

I'm leery about jump starting my SL, the last thing I (or you) need is to toast a computer or actuator.

__________________
Current Crop:
2002 ML500
1997 SL600
1969 Corvette (for sale, perfect shape)
1984 RX7 GSLSE

Wanted:
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Looking for a new SL.

First make sure you have copies of your radio / alarm codes etc.
Check the voltage of your battery.
It should read 12.6 volts fully charged.
Check your cable ends at the battery and at the starter. You may need to disconnect them for a good cleaning.
Check for a voltage drop when cranking .....Below 9 volts is a problem.
There is no true test for a battery.
It may read good but fail under load.
How old is it??
I had one battery last 11 years (motorcraft) and one last 8 months (die hard)
As you have described, it sounds like the starter may be faulty.
If you can....smack it with a hammer. In a tight place use a pipe to reach it and smack the pipe. This may jolt the amature and it may start.
Look carfully at the connection at the starter ....how does that cable look?
You can....with gloves, move the crackshaft by giving the belt a goog tug.
-Anthony

Yes leejxxxxx ..... I agree. No jumping. Try another battery first.
Yes a solenoid on the starter will corrode as well as the connection.
I agree that bad solenoid contacts will cause this condition. Again a good smack might make it contact. Of course a replacement is in order. You might be able to replace just the solenoid / relay part. I always take the time to seal the covers with RTV and coat the cable / wire connection with paint RTV or something. This area is exposed to the elements

I'm glad I'm not the only one who thinks this about jump starting.

I'll never understand what it is that affects battery life. I've had some fail on daily drivers within six months. I've got a car now I haven't started in 4 months and its battery is in good shape.

Phelan, please let us know what it was.

__________________
Current Crop:
2002 ML500
1997 SL600
1969 Corvette (for sale, perfect shape)
1984 RX7 GSLSE

Wanted:
a diesel MB!
Looking for a new SL.

Charged the battery and the car starts! whew!. Funny car would not start prior to charging with jumpers in place? Anyway a new battery Monday. What is the correct battery type and best make?.

I would recommend you get one from the dealer. It may cost you a few bucks more, but you will rest assure that it is the right one for the car. I found buying one from an auto store or Sears really does not save you all that much money. I knew because I bought one for my SL from the dealer to replace the OEM one that came with the car in '95.

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95 R129
04 Infiniti G35.5 BS
10 X204

Go to Pep Boys or Autozone for battery terminal cleaner (wire brush) made for the battery. They will also have a terminal coating in an spray can to help prevent corrosion. they will also have anti-corrosion impregnated felt rings to go under cables. Cheap insurance against non-starting.

Tim