Alternator
#1
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Alternator
How much do they cost new? and where do i get one from?
I suspect i may need a new one soon and want to be ready for the sting, obviously i'm sure the stealers will sell me one but i imagine it will not be cheap.
I suspect i may need a new one soon and want to be ready for the sting, obviously i'm sure the stealers will sell me one but i imagine it will not be cheap.
#3
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I've noticed it is getting really hot to the point you can't really touch it after a medium drive and also the red rubber cap on the top bolt keeps falling apart which i am putting down to heat.
I'm just expecting it to burn out or something although the car is starting ok and i have not noticed any other side effects bar the rubber cap falling apart.
I'm just expecting it to burn out or something although the car is starting ok and i have not noticed any other side effects bar the rubber cap falling apart.
#7
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If its getting very hot, its often a sign that the alternator is working extra hard to compensate for a insufficient battery capacity...normally due to the battery being half dead (still ok to start the engine but down a cell or sulphated, so the alternator has to put extra work in to maintain voltage and current demand).
A load test will quickly identify the battery's state of charge: http://jgdarden.com/batteryfaq/carfaq4.htm#load
To do the above test, the open circuit battery voltage must be 12.7volts or higher, if not, its not fully charged. If its below 12.2volts, its flat and is being damaged by sulphation as I type (yes, it can still start an engine in this state....for now). The same website also gives superb advice on how to make sure its 100% charged whilst avoiding excessive/damaging gassing of electrolyte via using a "dumb" battery charger.
A load test will quickly identify the battery's state of charge: http://jgdarden.com/batteryfaq/carfaq4.htm#load
To do the above test, the open circuit battery voltage must be 12.7volts or higher, if not, its not fully charged. If its below 12.2volts, its flat and is being damaged by sulphation as I type (yes, it can still start an engine in this state....for now). The same website also gives superb advice on how to make sure its 100% charged whilst avoiding excessive/damaging gassing of electrolyte via using a "dumb" battery charger.
Last edited by ALi-B; 13 December 2010 at 11:33 PM.
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#8
Had this problem on mine. It turned out the wire had come loose from the resonator which was causing sparking to happen during the charging cycle as the nut was half done. Due to this the end had melted and had to get a new resonator and wiring done. New resonator will cost you £40. All good now. Luckily I had a Scangauge II connected up to my OBDII port which showed abnormal charging and battry voltage being very low past 12Volts after stopping the car.
#9
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Resonator?
Never heard of that (well except for an exhaust or intake silencer or analogue audio electronics etc.).
Do you mean a "Regulator" by per chance? They are often found on the back of the alternator, usually as part of the brushbox.
Never heard of that (well except for an exhaust or intake silencer or analogue audio electronics etc.).
Do you mean a "Regulator" by per chance? They are often found on the back of the alternator, usually as part of the brushbox.
Last edited by ALi-B; 13 December 2010 at 11:40 PM.
#10
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I don't think its the battery as i had to put a new one on last month and the connection on top of the alt is nice and tight. I have had the battery output checked with the engine running and lights/radio on and it showed above 14 which i understand is normal.
Not sure what else i can check myself so it looks like i need to get it into a specialist
Not sure what else i can check myself so it looks like i need to get it into a specialist
#11
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#13
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Bought a new one for my "02" WRX here - £98 + £4.95 P&C + VAT
ALTERNATOR & STARTER MOTOR SPECIALIST
Hillmart UK Alternators & Starter Motors
Next Day Delivery on over 6000 units
QUESTIONS ABOUT THIS QUOTE CONTACT MARTIN
Enquiries@alternatormart.co.uk
tel : 0161 330 5466 lines open 8.30am - 4.00pm - mon-fri
Very quick delivery and comes with a test certificate
ALTERNATOR & STARTER MOTOR SPECIALIST
Hillmart UK Alternators & Starter Motors
Next Day Delivery on over 6000 units
QUESTIONS ABOUT THIS QUOTE CONTACT MARTIN
Hillmart UK Ltd
994 Astley Street
Dukinfield
Cheshire
994 Astley Street
Dukinfield
Cheshire
tel : 0161 330 5466 lines open 8.30am - 4.00pm - mon-fri
Very quick delivery and comes with a test certificate
#16
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Thread Starter
Just been looking at Magnetti Marreli ones, looks like a light weight version is a cheaper option.
Going into Richard Henry motorsport tomorrow for a diagnosis so fingers crossed its just a bad earth.
Going into Richard Henry motorsport tomorrow for a diagnosis so fingers crossed its just a bad earth.
#18
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My money is still on the battery; Not having a proper voltmeter reading on with it disconnected (and stood for 6 hours minimum to allow surface charge to dissipate) means its condition or state of charge is still completly unknown.
Checking voltage with the engine running doesn't prove anything: 14ish volts to all intents indicates normal alternator operation. The alternator's operation is highly dependant on the battery's capacity and state of charge. The only alternator failures I've seen is either no charge output (car eventually dies - flat battery), overcharging (battery boils its electrolyte dry), electrical interference or overnight battery discharge (diode failure) or noisy/slipping belt (bearing failure). They aren't complex devices so there is little to go wrong (bearings, coils, brushes, diodes and regulator that's pretty much it).
That Battery FAQ tells everything you need to know to confirm the battery really is OK. So long as one is wishing to spend some time reading it. Only tools required are a voltmeter, a battery charger..and a car.
Checking voltage with the engine running doesn't prove anything: 14ish volts to all intents indicates normal alternator operation. The alternator's operation is highly dependant on the battery's capacity and state of charge. The only alternator failures I've seen is either no charge output (car eventually dies - flat battery), overcharging (battery boils its electrolyte dry), electrical interference or overnight battery discharge (diode failure) or noisy/slipping belt (bearing failure). They aren't complex devices so there is little to go wrong (bearings, coils, brushes, diodes and regulator that's pretty much it).
That Battery FAQ tells everything you need to know to confirm the battery really is OK. So long as one is wishing to spend some time reading it. Only tools required are a voltmeter, a battery charger..and a car.
#19
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Thread Starter
the battery is less than one month old, is it still likley to be causing the issue. I'm seeing no problems with the car starting so it must be holding a charge.
I'm on a learning curve so Let's see what the garage say tomorrow.
Thanks for the help so far guy's
I'm on a learning curve so Let's see what the garage say tomorrow.
Thanks for the help so far guy's
#22
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Thread Starter
Ok,
So after leaving the car at Richard Henry's Friday morning they came back to me with...........
"We have tested the alternator and it is charging/working fine, we have put a different alternator onto your car and that is also working fine and is not over heating"
they have cleaned down the earthing points and also fitted an additional earth cable going from the alternator to the battery.
Not really a conclusion but i feel safe/safer its not the alternator at fault
I'm going to run the car for a bit and keep a close eye on things.
So after leaving the car at Richard Henry's Friday morning they came back to me with...........
"We have tested the alternator and it is charging/working fine, we have put a different alternator onto your car and that is also working fine and is not over heating"
they have cleaned down the earthing points and also fitted an additional earth cable going from the alternator to the battery.
Not really a conclusion but i feel safe/safer its not the alternator at fault
I'm going to run the car for a bit and keep a close eye on things.
#23
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Oh well, at least things seem "normal"... if it helps I will take mine for a run and see if my flesh sticks to mine on it's return...
dunx
P.S. How did the interview go ?
dunx
P.S. How did the interview go ?
#24
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Well i felt it went well but i can't have impressed them too much because they haven't called me back
Suppose moving into a retail based environment is a bad idea at the minute anyway never mind
#26
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In normal running the alternator will be hot but not so hot you cannot touch it.
When I check alternators I am looking for an output of 14-14.4 V and an absolute minimum of 13.5 V at which point it is time to be concerned.
As Ali-B pointed out, if there is a fault on the battery then the alternator can overheat as it is trying to produce maximum current output to no avail.
The most common faults we come across are bearing failures or noisey just before failure (Alcazars being one and a couple more since) Not an expensive repair or diode failure or one of the legs breaking. A bit more expensive because of the cost of the diode unit.
We keep one good alternator of each type minimum, there are two types covering cars 93-07 as far as I know, so if someone arrives with an alternator issue we simply swap alternators in half an hour and they are on their way. Switch over must have been around ver 5 cars I think. It is very rare to get a Subaru alternator that cannot be repaired economically.
That said, around £100 for a new one is very cheap if it is reliable.
Dealer £700 is a serious rip off.
When I check alternators I am looking for an output of 14-14.4 V and an absolute minimum of 13.5 V at which point it is time to be concerned.
As Ali-B pointed out, if there is a fault on the battery then the alternator can overheat as it is trying to produce maximum current output to no avail.
The most common faults we come across are bearing failures or noisey just before failure (Alcazars being one and a couple more since) Not an expensive repair or diode failure or one of the legs breaking. A bit more expensive because of the cost of the diode unit.
We keep one good alternator of each type minimum, there are two types covering cars 93-07 as far as I know, so if someone arrives with an alternator issue we simply swap alternators in half an hour and they are on their way. Switch over must have been around ver 5 cars I think. It is very rare to get a Subaru alternator that cannot be repaired economically.
That said, around £100 for a new one is very cheap if it is reliable.
Dealer £700 is a serious rip off.
#28
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No. The alternator generally produces a voltage of 14.0-14.4 volts, sometimes marginally more. If a lot of current is being produced because of a flat or defective battery the voltage may drop slightly and rise as the battery takes the charge and less current is being produced.
#29
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Thread Starter
Impreza ownership is one steep learning curve
Well i guess if the alt has been given the all clear and the earths are ok my next step is another new battery. After that i have no idea.
What if the battery i have in now is the wrong spec?
Well i guess if the alt has been given the all clear and the earths are ok my next step is another new battery. After that i have no idea.
What if the battery i have in now is the wrong spec?