Red light while revving low (sorry, no creative title this time)

[8bit Innovations]

My 67 bug has been having this problem for about two weeks and it’s driving me nuts! When the engine is idling, half of the time the generator light comes on. However, I start driving and the light goes away quickly. Just a light is not frustrating though, what is frustrating is that every time the light comes on, I hear an ever so slight rattle underneath the rear seat, which goes away when the light goes off. A mechanic concluded that the generator is not working properly, since the red light issue seems to get worse when the headlights are on (happened to me before it got worse). However, I’m not sure of the generator is completely at fault, because since seeing my 67 bug the mechanic wanted to make sure we keep it factory correct and remarked that the generator we have is not the correct one, although I still wanted the car to have the correct push terminal generator. Anyway, the main question: Is my generator really at fault or there may be something else at fault?

P.S: I replaced my normal size battery with a smaller sized new battery, which seems to kinda have helped in the problem, but not by much.
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[rcroane]

Battery cables all nice and tight? Just wondering if the light and the rattle under the seat are related to the new battery installation.
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'65 Sunroof Bug

[Zundfolge1432]

Not a problem now. When light comes on and stays on you’ll have a problem.

[iowegian]

If I am not mistaken the '67 Beetle voltage regulator is located under the rear seat, so--------------

[8bit Innovations]

Addressing the recent replies:

1. The battery cables were tightened even better than what they were before. The rattle comes just from the left side of the rear seat. Thanks for the suggestion though!

2. Thanks for the reply too! At least now I know the car is drivable!

3. The regulator. That’s what the mechanic and I initially suspected. However, the other problems he mentioned include, lights dimming while idling, and needing to rev the engine a bit when arriving from a drive with the lights on. All of those problems had been occurring for some time before the light came on even when driving with the lights off. Is the regulator rattle associated with the generator failing though, or is that an excuse made by the mechanic to replace the generator??
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[mukluk]

[67rustavenger]

The rattle under the back seat. Is likely the VR points clicking closed and open at a very high rate.
You can change the VR to a solid state unit from Bosch. Or live with the OG one that you currently are running. I have a SS VR in my 67 and it works flawlessly.
The dash gen light glowing at stop lights is just the nature of the electrical system. The lights dimming when idling is a result of the gen. not charging at idle. Once the engine is revved. The gen. light goes out and the gen is charging the battery.
An alt. charges continuously. From idle to full driving RPM. But an alt. is not stock on a 67.

If this is the Savannah Beige car in your gallery. I'm super jealous. It's a beautiful car indeed.

If you are living in PR. I'm jealous too. I miss the island. I worked there in 2001 for a year and really enjoyed the life style, culture, and the roadside Kiosks that offered some of the most delicious foods any person can ever eat.
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I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[viiking]

Definitely the VR under the back seat, chattering as the points open and close.

Note: Generators do little to NO charging below 1000rpm engine speed. The rated output of the 12V generator is about 360W @ 12V at 2000 generator RPM which is twice the engine speed. So if your engine is idling typically below 1000 rpm not much juice is being provided.
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1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[Eric&Barb]

It could also be you have an earlier crankshaft pulley that is too small.
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In Stereo, Where Available!

[8bit Innovations]

Thanks for the quick responses to everyone! I’ll give you an update when I work on the car.
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[lboos]

Sounds like your idle rpm is just too low, that would cause the light to flicker at idle, also can cause noise because of a rough idle. increase your idle rpm.

I don't think you could hear the VR making any noise, esp. with the engine running, but you can hear a lot of rattling/tin if the engine is running rough, like too slow of an idle.

[KTPhil]

[8bit Innovations]

Adressing the most recent responses:

1. A quick check on the engine compartment and the pulley the correct one. Since it is a 67, the engine tin needs holes for the preheat, and in the one I have the pulley fits with almost no gap at all. Thanks for the suggestion anyway!

2. Today I drove the car again. The light came back on at random times. Never while driving, but at some stops it came on and at some it didn’t. Could be idle, however it may be something else combined with idle. Since the engine feels exactly the same as it felt when the light didn’t come on.

3. I suspected also that the regulator itself may be failing. However, I can’t be sure if it always rattled. In some of my older threads, I mentioned that I removed my door mechanism. What I never mentioned was that after installing the door panel, the armrest rattled a lot. Only after replacing the armrest like I planned to did I notice the VR rattle. However, before I noticed the rattle, the light were dimming everytime I drove at night. Would you suggest replacing only the generator, or the generator and regulator too?
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[8bit Innovations]

Reading in more detail at the responses here, some of you have said that it’s normal for regulators to make a faint clicking noise. Is there an explanation as to why do regulators make noise normally?
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[KTPhil]

There are internal relays that are opening and closing.

But when they sound like a machine gun something is about to fail.

https://www.thesamba.com/vw/forum/viewtopic.php?t=485607
https://www.thesamba.com/vw/forum/viewtopic.php?t=663656

[modok]

Old regulators have moving parts inside, so they probably do make a noise.
It could fail in a way where it makes more noise. Other times it quits entirely if the contacts weld solid which would be silent but deadly.

Solid state regulators do not, but they might emit a high frequency humm which none of us can hear because of age

If the generator tests good replace the regulator, or, probably just replace the regulator. It's worth the risk of having a spare if you guess wrong.

[8bit Innovations]

Now I understand how those old school regulators work. I remember that my mechanic talked about something inside the regulator that opened and closed rapidly. However, he never said that it was bad. Instead, he said that the noise was caused by the generator making way too little electricity. Is that true? Or do failing generator not affect regulator noise? Either way, I’ll be getting a solid state VR just in case. Might end up replacing both things out of fear of getting stranded.
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[Q-Dog]

My generator has about 300,000 miles on it. Only have replaced brushes in it 3 or 4 times that I can remember. It takes a bit if abuse to kill a generator.

But I have probably replaced 8 or so regulators with that same generator. I highly recommend the solid state regulator.
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Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[8bit Innovations]

Due to collective recommendations from people here and in the jbugs webpage, I have now ordered a solid state regulator. Mine may not be dead, but I still find that since the generator will be replaced the regulator should be replaced too. Either way the generator was due to be replaced since it was not factory correct. At least my grandpa and the mechanic know of a guy that has been rebuilding generators since my grandpa owned a peugeot back in the day, and he may be able to give the new generator a rebuild, since it is a bit rusty and it may not work properly, but at least it’s the push terminal one. Thanks for the suggestions and responses to everyone! I’ll give you an update when the stuff is installed.
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-8Bit

67 Bug Puerto Rico spec Deluxe sedan Fontana Grey (Acquired from original owner’s family)

[KTPhil]

Search for "polarize generator" and consider doing that to your new gen. I've never had to, but some have needed it.