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Old 08-13-2021, 09:40 AM
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andrewwynn andrewwynn is offline
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Location: Racine, WI
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Random cranking issue, M57 diesel 2003

Most likely correct assessment.

Common failure mode of a starter is to pull more and more current as it fails. It presents with the symptoms you described.

Get a measurement of the current draw when starting.

It should be in the range of 225-275A. When failing they can be 350-400a.

225a is my gas 3.0 on cold start, 185a on immediate restart. I'm suspecting the second attempt the engine has enough oil in the right places to get that drop in torque required.

It can take years to slowly fail and the only symptom is it cranks slower and take longer to start (though it will often take out an aloder weaker battery so more often than not people replace the battery first not realizing it was the starter not the battery in the first place. )

Start the car with a fully charged battery but also jumper from another running car.

If it starts fast almost certainly the starter.
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Last edited by andrewwynn; 09-01-2021 at 07:34 AM.
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