Vauxhall Astra MK5 H Diesel losing Power

Hi all,

Iam looking for some advise with a problem iam having with my Astra.

Afew nights ago, my girlfriend was driving it and suddenly the power steering went, then all the lights and power, she managed to park it and called Green Flag, they said it was a faulty battery, so i got a new battery and fitted it, that lasted about 2 miles before the same thing happened. So i think its the alternator.

Vauxhall want £410 and then fiiting for one, ive managed to find one for £188 from Halfords. First i want to test thats it the alternator, iam just changing the battery so i can put a multi metre on the battery when the car is running, am i right it should read about 14 volts and if it less than 12 volts the alternator needs changing?

Iam going to fit it myself, anyone know if its an easy job, my Haynes says it is.

Any help would be great.

Thanks

Warren

Astra H 1.7D?

The alternator on that engine has the brake servo vac pump on the back of it, it means there are a few more pipes to deal with including a messy oil feed pipe, its not too difficult to change it.

Battery with no load should be a steady 13V - 14V, if there is less than this at the battery there are a few things to check before you replace the alternator! With the car running for a few mins (if thats possible) make sure the battery terminals are not getting hot where the thick wires are crimped in place, if they are getting warm/hot this is certain to indicate a high resistance which will stop the propper voltage reaching the battery.

Another thing to check is the earth lead that bolts to the rear of the engine on the end of the 17mm starter motor bolt! I have seen these loose (come loose or left loose I dont know) but if it is this will prevent the battery charging.

Final test and its a tricky one is try and get your positive multi meter lead onto the back of the alternator on the main feed out, if the voltage is low there then that is almost certain to be a goosed alternator. Oh make sure your multi meter neg lead is placed on a good earth point on the engine.


Hope that helps.

If the battery voltage is 14.0+ with the engine running the alternator should be OK. Never met that alternator, sounds a bit of a pig.

warren100uk said:

called Green Flag, they said it was a faulty battery

Click to expand...

Green flag, you got to love 'em. Still you get what you pay for........

Will be the alternator, trust me. As An AA Patrol I see and accurately diagnose defective alternators on Vauxhalls with exactly the same symptons as discribed by you.

Slim possibilty is a broken or burnt out wire on the back of the alternator. You will need to conect your multi meter there to see what the voltage is. Is you get battery voltage then you can confirm dead alternator.

Hi again,

I have changed the battery up, and it reads 12 on my meter, is that ok?

Also what should it go to when the engine is reeved, to see if the alternator is working?

Thanks

When the engine is running you should have at least 14 volts.

Morning all,

On Friday, i got a mechanic out to come at find out the fault, this was before i thought it was the alternator, when he got here, the car wouldnt even turn over, just dead. He said it was because the battery was dead and i needed to charge the battery. He was wrong and a waste of £40.

I have charged the battery and it still will not start or turn over, if the alternator is faulty, should the car still start?

Also Greenflag told us it was the battery, so i got a new one, i have just put the multi meter on the old battery and it show 12v, does this mean its ok?


Anyone got any clues as what could be at fault?

All this seemed to start after the fuse for the wind screen system blew.

Also everything else electrical works, with the charged battery.

Any help would be great.

Thanks

The battery can read 12 volts off load and still be dud, check the voltage across the battery when you engage the starter, if it still reads 12 volts thenyou have a problem with the starter or associated circuitry, if it reads practically zero the battery is flat, not necessaraly faulty, try charging it.

If the alternator is faulty the car will not start because the battery will be flat

Cheers Peter,

Had Greenflag out again,and they cant get it to start.

He trired to hot wire it and that wouldnt even work.

The battery is fully charged and this is a different problem than the alternator, maybe it to do with the security system. Cant even start it to test the alternator.

Am at a lose, will have to get it towed to a Vauxhall Garage.

Thanks