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[RichB]

Well I am having more problems again with the battery and alternator.  Had 2 flat batteries today, car had only been stood 5 hours the second time...

Right so when the engine is running car struggles to make 13.5 and seems worse when its hot 13v maximum.

When engine is hot and I turn everything on then it struggles to make 12.5v sometimes 12v

Tried another battery and I am getting same results.  So I am pretty sure that the alternator is knackered  I have ran new earth cable for the batter but not new power cable as I havent had the time, should I check voltage at the alternator before changing it?  I am quite sure you cant get that much voltage drop over a cable, it seems to not get hot, does get warm though after a run.

Also i'm sure I read on here that someone does reconditioned alternators on exchange in Nottingham?


Cheers,

Richard

[Kevin Wood]

Worth checking the voltage at the alternator terminal just in case there's a bad connection. The crimping of the positive cable to the positive battery terminal is a favourite. Does this terminal get hot when the engine is running?

Kevin

[iainb]

Hi RichB, have you cleaned the battery terminals they should be clean and bright. The voltage should be a lot higher with the engine running than you quote here. So it does sound like your alternator is on its way out
Cheers

[Darth Loo-knee]

Have you looked how to repair your alternator could save yourself quiet a bit of money mate.

http://www.omegaowners.com/forum/YaBB.pl?num=1153772945

[RichB]

Cheers for the replys guys.  I guess I could fetch the alternator off tomorrow and have a look at it, is it dificult to remove?

The positive terminal does get a little warm but not too hot.  I have some cable that I could run from alternator to battery but routing it looks like it might be a problem, I guess I should take alternator off and have a look at the connections then.  Do you have to change the bearings or will cleaning it up if its corroded do the job?


Cheers,

Richard

[Matchless]

Normal voltage with a healthy alternator is around 14V.
Usual cause of no output is corrosion to the spring contact going to the regulator as shown in Marks guide so take it off and have a look.

Disconnect battery before trying to get a spanner on the rear fixing....you will see why once its off.

[v6coop]

I have ran new earth cable for the batter but not new power cable

Do you mean you have replaced the thick negative (earth) cable down to back to the pump bolt with a new Vx replacement?

[RichB]

I have ran new earth cable for the batter but not new power cable

Do you mean you have replaced the thick negative (earth) cable down to back to the pump bolt with a new Vx replacement?

No I just ran a second cable from the battery to the earth point, I clened it up a bit to make sure it was getting a good connection.  The power cable looks like a bit more of a job trying to route it.  Also where is the earth cable from the engine to the chassis?


Cheers,


Richard

[feeutfo]

did this job on my old mig, it was covered in oil from cam covers, and failed. Access is main problem as exhaust and various chasis part are in the way from under the car. Get it up on both axle stands to give yourself room. And it helps to have a mate from the top with the bag pipes removed to hold the other end of the bolts. Cant remember the exact order but remove one or other bolt, bottom one probably, then twist/pivot the alternator on the second  to reveal  nut/bolt above. I found it a pig. Easy in theory its 2nuts and bolts and 2 wires, with the air intakes removed. Access is the problem. Hth.

[Bandit127]

Normal voltage with a healthy alternator is around 14V.
Usual cause of no output is corrosion to the spring contact going to the regulator as shown in Marks guide so take it off and have a look.

Disconnect battery before trying to get a spanner on the rear fixing....you will see why once its off.

Yes, 14V minimum. 14.4V is normal.

You can meter out the cable by running the engine up and measuring the difference between the terminals at the 2 ends of the cable. You should have no more than 0.1V. If so, the cable is OK.

I think your problem is the alternator though. From your measurements, it looks like it's not charging.

Don't be fooled by the 12V rating on the battery either. Fully charged, it should put out about 13.2V

[unlucky alf]

i bought an opel monza a few years ago with the same problem & found it was no earth to the engine block itself, in fact it made all the gauges on the lcd display read incorrectly as well as not charging properly.

[Marks DTM Calib]

Think I have a known good one in the garage with new bearings fitted....

[RichB]

well I am trying to get this alternator off but can't get the top bolts off. I can't get access to the top bolt at the back. Mark you are only down the road so could get that alternator. How much would you want for it and would you be able to fit it? I have been trying to get this stupid bolt off for over an hour!

[RichB]

Well eventually got the alternator off, the top bolt was a problem until I used a small torque wrench from uunderneath, my ratchet is too big!  Cleaned up the alternator although it didnt look too bad.  Refitted with a second power cable, some nice 4AWG.  Getting the belt on was ridiculous, it took 3 of us as it was so tight!  I dont know how I managed to get it on by myself last time, should it be that difficult?  Its a genuine Vauxhall belt aswell.  Anyway it looks like I will need to try a new alternator as it still isnt working.  Strange as it gets worse when the engine has been running for a short while.  I will be picking up a new alternator from Mark at some point this week and starting all over again

Hopefully will be able to do it a bit quicker next time now I know how to get at everything but I wont be able to get the belt on unless there are 3 of us again.  We had to hook it over all the pulleys etc and tensioner and then force it onto the big roller in the middle with another person turning the crank pully aswell, what a job!

If anyone wants to volunteer to help me do it next time then give me a shout.  

Cheers,

Richard

[v6coop]

Before you change the alternator try measuring the voltage again when the car has warmed up. Measure it across the battery terminals with the engine running. Assuming it is still reading 13V or so then try leaving the meter probe on the +ve terminal but this time push the     -ve probe through the insulation on the thick brown wire 3 to 4 inches away from the battery terminal. It won't matter that the insulation is punctured on this cable. I wonder if you have a problem with the cable and if so measuring it again as above you may find the voltage goes back up to 14V ish further away from the terminal. This would suggest the cable needs replacing.