Screeching starter motor
I have a 1993 SWB 300GE petrol.
Every now and again the starter motor screeches when I turn the key to start. I turn the key off as soon as I hear the noise. Sometimes it starts normally on second attempt. Sometimes it might take 2 or 3 more goes. This might happen once per week or once every two weeks.
So far it's never failed to start because of this but I'm worried that maybe I'm living on borrowed time so can someone please explain in layman's language what is happening and why?
And then what should I do about it? Assuming my starter motor might be on it's last legs, are there people who rebuild starter motors and is this likely to be cheaper than buying a new one?
Not sure I feel confident about removing existing starter motor and fitting replacement - I imagine there is some tensioning of belts involved. How easy a job is it?
As always, any help much appreciated.
Mark
On the plus side ! You did fix that rear window heating element !
So at least your hands will stay warm pushing it 
If I am not jumping the gun in my prognosis, it seems that your starter pinion is not engaging or meshing into the starter ring gear. Should the teeth of either the ring gear and, or starter pinion have been damaged then you are looking to renew both.
For the starter ring gear it is a gearbox out job.
The starter pinion can be replaced by almost any auto electrician shop which would recondition alternators, starter motors etc. If it is not possible to inspect the starter ring gear by trying to look through the bell housing, turning the engine clockwise viewing from the front of vehicle rearwards. The engine turning may be done by short bursts of cranking or levering with a flat blade screw driver to turn. Otherwise the starter motor will have to be removed to check the ring gear. Should your starter motor have cover with the engine 70,000 mls - 80,000 mls, my recommendation would be to have the starter reconditioned as well or at least a new set of brushes.
On the cheery side it could just be poor connection on the starter motor or solenoid causing a poor throw of the pinion making it crash. Check battery condition and connections and earthing.
For the starter ring gear it is a gearbox out job.
Thanks Rakesh.
Does that apply also if it's an automatic?
Yes, manual or automatic, gear box out.
Now you know that's not really the answer I wanted. 
Fingers crossed it's something that doesn't involve that.
Gearbox out to replace a starter motor ?
You're making this up surely ?
Why? - I hear you have to take out all the dash and advisable to also remove front seats just to change the heater rheostat.
In fairness to Rakesh, gearbox out only in event of starter ring gear problem (not actually sure what that is but think that replacing starter motor can be done without gearbox removal).
Yep you are right !
I hadn't computed Rakesh's instruction correctly ! He does indeed say "ring gear"
It just seems bonkers that to simply maintain parts which are known to wear that an easier method of replacement is not engineered into the design !
Well if your ring gear's shot old chum then you is gonna be facing a mission ! For shur !!!
Starter ring gear renewal Thank fully is not an everyday occurrence. I suggest checking out the ring gear initially as I have described it and starter motor connections firstly.
Rekesh is correct about the starter ring, but from experience the starter ring will take a reasonable amount of abuse before it needs to be changed. I would clean up the starter motor terminals and if possible test it on the garage floor with a set of jump leads. If the motor is old then better still would be to replace it with an exchange unit. Try EURO carparts for an Bosh unit (approx £170 +vat).
Hi Mark, a fairly local man to do starter motors is Alan at Direct Power near Petersfield. He's done them for me before. Phone number is 01730 710210
Hope this helps.
Regards, Rowland.
Just thought I'd update this thread in case it might help anyone else or maybe it will lead one of the "wise ones" to think "Ah, in that case it means ................"
Anyway, I haven't done anything about replacing/removing or otherwise repairing my starter motor except for the past 4 or 5 weeks when turning the ignition key I've paused a beat just before the stage which operates the starter motor. That's instead of the "old" way of starting which was to turn the key all the way round in one quick motion. Since I've been doing that I've had absolutely no problem.
Does this indicate anything to anyone or is it just coincidence?
No doubt, when I get in the G later today I'll follow my new procedure and will be greeted by a screeching starter motor.
Maybe you are allowing the battery a moment to recover from the initial surge of powering-up the instruments and ignition system.
...or it's just a coincidence, as you say.
But do you know if your battery is good?
Thanks Arnie,
Is there much battery used in powering up the instruments and ignition system (my radio is on permanently by the way)?
Not sure of the correct technical terminology but I wondered if the starter motor is engaged by the key being in the position just before the starter is fired (the next key position)? If so, maybe the starter is a bit tired and needs that moment to engage??
How can I be sure the battery is good. I have a digital multimeter but I think that can only cope with up to 10 amps.
The starter is pre-engaged, which means that when you turn the ignition to position-III, the starter solenoid is powered and this first pushes the starter pinion gear forwards to engage with the ring-gear on the flywheel.. As the pinion-gear becomes fully engaged, two large contacts close which power the starter motor to rotate. Therefore, the sequence is somewhat fixed and does not depend on how fast you turn the key.
A battery in good condition should hold a voltage of between 12v and 12.5v when the car is left for a long period of time, such as overnight. If you measure, say, 11.5V, then you can suspect that the battery may not be at its best. However, a battery load tester is best for the job.
I would imagine that you may be drawing 10 - 12 Amps when turning-on the ignition, with the radio on (The standard radio fuse is 5A so should not be more than that). Also, going quickly from position-II to III may not give much time for the fuel-pump to prime.
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I had thought of that but I'm pretty sure the heating element only operates when the engine is running