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[Dave G]

Hi,, just setting off on first leg of our holiday - Alternator/Charging light blinked then stayed on. Dashcam switched off a few mins later (low voltage) then engine management light came on. So I got off the motorway and back home asap. Pedal Error code is giving me 0571, which I'm assuming is because of low voltage rather than being the actual fault (0571 is Cruise control/brake switch 'A' circuit malfunction).

Battery is at 11 volts, just enough to start, but no increase when engine is running. Does this sound like alternator, or are there other things I can check first?

Cheers,
Dave

[Nick W]

You must have a multi-meter to know the battery voltage, which ought to be nearer 12.5v with the engine off.
That ought to rise to at least 13.5 with the engine running, and around 14v would be better. That shouldn't change if you turn on some of the higher draws like the heater fans, lights, rear screen demister.
So yes, you have an alternator fault.
But, do check the running voltage at the alternator output stud before you condemn it; the problem might be a poor connection in the wiring.

[Andy H]

When that happened to me it was the regulator in the alternator.

Unlikely to be caused by the wiring because the alternator & starter share a lead to the battery. (do check the wiring though - the crimp connections fail over time and get very hot when passing 200A to the starter, they get less hot passing 120A from the alternator to the battery)

[Dave G]

Thanks for the suggestions - and yes I have a meter to do those tests. I've ordered a new alternator to be on the safe side as time isn't on my side, but I'll do the checks you suggest as wel.

Thanks again guys...

[Doctor Gollum]

Kevin Wood has written an excellent guide for starting/charging diagnosis. Work through it step by step and act on the results 

A poorly fitted accessory such as a dashcam won't help matters. So run the tests with it plugged in and unplugged.

[Kevin Wood]

The other thing to check is the crimp where the battery cables join the terminals. If they're getting hot while running, there'll be enough voltage drop to prevent the battery charging, and often that will happen before the starter is affected.

If there's no output from the alternator, it's most likely the regulator pack, which is an easy and cheap fix.

[Kevin Wood]

Diagnosis guide:

https://www.omegaowners.com/forum/index.php?topic=90619.0


Regulator replacement:

https://www.omegaowners.com/forum/index.php?topic=90512.msg1155346#msg1155346

I have bought regulators from these guys in the past with good service: https://www.rotatingelectrics.co.uk/

[Andy B]

The other thing to check is the crimp where the battery cables join the terminals. If they're getting hot while running, there'll be enough voltage drop to prevent the battery charging,  .....

I had this when I had my Omega. The charge light would glow very slightly and get a little brighter when rev'ed. I borrowed a big set of crimp pliers from work and tightened the crimp. It only tightened very very slightly, but it was enough. 

[Dave G]

Well the new alternator is in now - but i cannot for the life of me get the belt back on - it looks too short for the new alternator. It's fitted with a 6PK2020. Do I need a slightly longer one - if that exists??

[Doctor Gollum]

Is the alternator pulley the same size as the original?

Diesel and 3.2 alternators the same but pulley different size.

Presumably you've routed it correctly?

[Nick W]

Well the new alternator is in now - but i cannot for the life of me get the belt back on - it looks too short for the new alternator. It's fitted with a 6PK2020. Do I need a slightly longer one - if that exists??

That's the correct belt.
Does the new alternator have the same size pulley as the old one?


But more importantly, how are you fitting the belt? If you're trying to fit the last part over the tensioner pulley then you're making things difficult. It's much easier to run the belt over all of the ribbed pulleys, use a long spanner/ratchet on the tensioner and slip the back of the belt over the smooth water pump pulley.

[Dave G]

Yeah, pulley's the same size, belt routed correctly. And I'm routing over the pump pulley last - or trying to - the belt's just too short.

Just thinking the pulley is offset from the mounting holes by a few mm more - increasing the path length. Measuring with wire with the tensioner released gives me more like 2030, rather than 2020. Going to have to give it a try - holiday's supposed to start tomorrow !!

[Doctor Gollum]

Could be the wrong alternator.

Also, the wire you're using for measuring will seem longer because the tension won't be the same as the belt.

If you can, use a different socket/spanner on the tensioner in order to ensure maximum movement as you fit the belt to the waterpump. An extra mm or two could be all you need.

[Enceladus]

The spring in the tensioner is quite strong. Try a socket with a short breaker bar, makes it a little easier to pull the tensioner to it's limit stop. Also there's a little drilling in the tensioner that you can use to hold the tensioner at the limit stop while you get the belt on. New GM tensioners ship with a rod inserted in the drilling. A drill bit works well as a substitute. I can't remember the exact size of the hole, 3mm or 4mm perhaps?

[Dave G]

I’m using an old torque wrench on a socket, so plenty of leverage. Good info about the drilling. I’ll check that out as it will save my wife pushing the bar while I struggle with the belt!

As always, thanks for your help.
Cheers.