2001 V5 Bora headlights and dashlights flash/pulse at idle

[Woo]

Hi,
Got a V5 Bora with about 150k on the clock. Sometimes when it is sitting at idle the headlights and dashlights will flash or pulse badly enough that you notice it where the headlights shine on other cars or the ground or whatever. I mentioned this to the mechanic today when I dropped it in for a service because I thought the voltage regulator in the alternator was on the way out. He sent it to the auto elec who rang me and said he could see the pulsing/flashing and described it as "pretty bad actually" (very technical ) but he tested the charge rate and notice minimal fluctuation (0.2 volts) so he felt that unless the issue was amplified when it got to the computer, the alternatofr was not the cause. I priced getting it replaced anyway and he said that it was the original Hitachi alternator that - because it has a clutch in it - had probably outlived it's life expectancy anyway, but he was not confident that this was the problem and told me he was trying to save me $700 and didn't want to replace it if it wasn't the issue. Can anyone tell me if 0.2 volts fluctuation in charge rate could cause this sort of issue? If not, could there be any other cause for the flashing/pulsing lights? The car is totally stock and the only other issue it is having is that the temp gauge has stopped working - but the mechanic is rectifying this during the service because he thinks it needs a new sender unit, so I don' think this is in any way related to the lights flashing. Thanks, Woo.

[craig_the_german]

My golf had the same issue, pulsing headlights, dash lights, could even hear the electric window motors pulsing when the windows were going up and down (all with the engine running) It even caused the engine to serge in time with the lights it was that bad.

Changed the alternator - problem fixed.

[balkanac]

When you get weird elec issues like that its the alt 90% of the time. Maybe get someone to check it out properly, a VW specialist maybe

[Woo]

Just as I suspected, thanks for the confirmation guys, looks like it's a new alternator next week!!

[Woo]

Sorry to drag this thread back up again, but I picked up the new alternator today but I'm still waiting on the new tensioner pulley that VW ordered from Singapore nearly 2 weeks ago (figure I may as well replace the tensioner and belt at the same time) I'm toying with the idea of replacing this myself, but I can only find "how-to" guides for the V6 and it looks like a pig of a job - the guides all say bumper and engine mount need to be removed, engine either raised or lowered, and the alternator taken from the bottom of the car (or through the top if you remove intake manifold) etc. If it's the same for the V5 then I'll take the parts to the auto elec and get him to fit them, but if someone on here can tell me it's a simple job and 2 or 3 hours work then I'll give it a go.

The only reason I ask is because the dealer quoted $1550 to replace alternator and tensioner (belt not included). The auto electrician quoted $960 for the alternator, $200 for the tensioner (which is fair, that's the cost from VW and he has to take to old one off anyway) and $100 for the new belt, plus he's estimated 2 hours of work $176. So far I've bought the tensioner for $200, a new Bosch 120 amp alternator for $400 and a belt for $60. The Auto elec has said he'll fit it all for $88 per hour but if it's easy I'll do it myself and have the satisfaction of fixing my car and saving a bag-load of cash.

[craig_the_german]

Hi Woo,

I did mine myself but mine is a 1.6L. I'm guessing the V5 may be different but mine came out through the top.