Strange issue -- Clicking Sound and Oil Pressure Light

[herewego]

Strange issue with my 1973, which is otherwise running well and is well maintained.

In a certain RPM range -- probably 1500-2500, in neutral or in gear, I'm hearing a distinct clicking sound that seems to be coming from the driver side rear. It's easy to hear in the car, seemingly from behind the back seat, but I haven't been able to hear it much or at all in the engine compartment, maybe just because the engine noise drowns it out.

I thought it was just another rattle or vibration at first. But it sounds more electrical, like a switch or solenoid kind of click. In addition, I noticed last night when I was running it in the dark that whenever the clicking sound is happening, the headlights seem to flicker a bit, AND the oil light flickers on, faintly but with increasing intensity with RPMs in that range. I'm quite certain that there is a connection between the clicking and the oil light.

Any of this ringing a bell for anyone? I'm wondering if I have a faulty oil pressure switch or a bad connection. I'll test for these when I get a chance, but I'd love any thoughts you have in the meantime.

[Semper_Dad]

Clicking from the rear usually indicates a CV joint is going bad. Clicking will increase or decrease relative to vehicle speed, not engine speed.

Can't think of anything electrical on a stock vehicle that would make that kind of noise.
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Walküre Restoration Thread: https://www.thesamba.com/vw/forum/viewtopic.php?t=737492

[jakokombi]

You don't have an electric fuel pump, do you?
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70 Sunroof Kombi
85 Motherfukinvanagon
73 Thing
72 Baja

[herewego]

No, it’s a stock setup.

[kenj06]

Pump for the gas heater?
The sound wouldn't be in the rear but it does click and mine dims the headlights and dash lights.

[Gene Kisner]

Drivers side rear? Clicking, like a relay cycling? Lights flicker? I think it looks (sounds) like your voltage regulator is doing a lot of cycling. Since it is fastened to the firewall it would act like a drum, therefore sound louder in the car. Check for loose connections, especially the battery terminals.

[Wildthings]

Check the brushes on your generator for wear. If the outer end of the brushes doesn't extend out of the brush holder your brushes are shot and should be replaced before running the engine any more. If the commutator where the brushes rides looks uneven and badly burnt it might be time for that alternator you have been dreaming of or at least a factory new generator assuming they are still available in these Covid times.

[herewego]

[herewego]

[Gene Kisner]

Have you found anything yet?

[herewego]

So, we had one day of warm weather here in Wisconsin, and I was finally able to replace the voltage regulator with a new Bosch unit that I ordered from TTS last Fall.

The good news -- the clicking sound has stopped, so I think the VR must have been the issue there. The bad news -- when the car warms up, the oil light still comes on and stays on. I change the oil and check the level regularly, so no issue there. No now I have to apply my limited skills troubleshooting to the cause of the oil light before I'll feel comfortable driving it again.

I appreciate all of your help on this! And, of course, welcome any oil light troubleshooting tips.

[Semper_Dad]

You have two options

1) Remove the oil pressure sensor and hookup a mechanical oil pressure gauge. Readings should be 25-65 PSI

2) Remove and test the oil pressure switch itself.


Link

This video shows a two terminal sensor. In our situation, the body of the sensor is the other terminal


Don't buy cheap Chinese switches. Go for a good German one like Hella. Careful though, there are counterfeit Chinese posing as German ones
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Walküre Restoration Thread: https://www.thesamba.com/vw/forum/viewtopic.php?t=737492

[herewego]

Thanks. I'll get after it.

[mainstreetprod]

[herewego]

[herewego]

Still no luck. Pressure test shows mid-40s, installed brand new Hella switch, oil light is on steady red. On top of that, I'm now getting a brake light, even though I've only driven a few miles and there is no visible sign at the pedal, at the wheels or at the master of any issue. Extremely frustrating, since our driving season here is short, and I'm at a bit of an impasse.

I wonder if I messed something up when I changed out the voltage regulator? I did it carefully, wire to wire, so I really don't think that's it.

In any event, I'm going to have to find some local help when time permits. Probably sounds like I'm whining -- more just disappointed that I can't get this right, and I'm going to miss the local show next weekend. @#$%!

[Wildthings]

If when the engine is running and the light is on, what happens when you remove the wire from the oil pressure switch? Does the light stay or or go out?

Did you order the replacement switch by application or by the part number on the old switch?

[FJBLF]

I would start by replacing this one..


Link

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1972 VW 181 SAFARI 1500 cc GRB Trans-axle

[FJBLF]

Then, I would build one of these...


Link

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1972 VW 181 SAFARI 1500 cc GRB Trans-axle

[herewego]

Finally got this figured out, with an incredibly helpful day-long visit from Robbie at Airschooled.

My replacement of the voltage regulator did solve the clicking problem. However, shortly after replacing, I was getting both an oil pressure light and a brake light. Weird.

I gauged the oil pressure -- no issue; I replaced the pressure switch with a brand new Hella unit, but unfortunately the problem did not resolve. Weird.

As we worked through it, Robbie noticed that one of the wires was not completely seated on the voltage regulator -- the plastic sleeve on the connector was seated, but not so much the wire, which (it turns out) is important.

The disconnected wire was the one that works on both the generator light and the brake light. So why was I getting an oil pressure light? Robbie correctly surmised that, at some point over the last 50 years, someone had done some electrical work and switched the oil pressure light and the gen light where they connect behind the speedo. We opened up the dash, switched the wires (and cleaned things up a bit), and presto!

All is well, and thankfully I never really did have an oil problem. Thanks to the people who contributed to this thread, and especially to Robbie at Airschooled, for the great detective work.