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tbonetoby14 Samba Member
Joined: October 31, 2025 Posts: 4 Location: Chesapeake, Va
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Posted: Sun Nov 16, 2025 12:53 pm Post subject: Oil light at idle |
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| I see this has been covered plenty but need a little help. 1500 engine. Not sure exactly how many miles or when the last build was. I changed the oil back around the beginning of Oct with 15w40. Been sitting for a few weeks since I’ve been trying to replace the generator. Finally got it back up and running and took it for a spin and when I got home the oil light came on while idling. Not sure if replacing the generator is at all related because the correct fan is installed properly. I understand this is common but my drive was only 15 min or so off the highway. I’ve read that it could be any number of things from needing a full rebuild to just needing thicker oil. Not sure what to try first, if anything. Any advice? |
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rcooled Samba Member

Joined: September 20, 2008 Posts: 2854 Location: Santa Cruz, CA
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Posted: Sun Nov 16, 2025 1:07 pm Post subject: Re: Oil light at idle |
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| tbonetoby14 wrote: |
| Any advice? |
Without knowing the history of the motor, it's pretty hard to tell what the issue could be. Replacing the generator shouldn't contribute to low oil pressure on its own.
If you have access to an oil pressure gauge & sender, you could measure it to be sure. You should see about 10-15 PSI at idle when at normal operating temperature.
What's the idle speed? If you turn it up a bit, does the green light turn off?
One thing you could try is to grab hold of the crank pulley and give it a good strong pull in & out to see if there's any axial play. If you feel any at all, it's a sign that the motor might be ready for a rebuild. _________________ '63 Ragtop (current)
'65 Ghia coupe (totaled)
'67 Ghia convertible (current)
'69.5 Ghia convertible and
'62, '63, '65, '69 Bugs (all long gone) |
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tbonetoby14 Samba Member
Joined: October 31, 2025 Posts: 4 Location: Chesapeake, Va
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Posted: Sun Nov 16, 2025 2:13 pm Post subject: Re: Oil light at idle |
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| After I bought this bug back in June I lowered the idle a little bit but still didn’t have the oil light come on. And yeah when I just bump the gas the light goes out almost immediately. I went ahead and raised the idle speed again to where the light is out. I’m not entirely sure what the idle is at now. I know it should be around 900rpm. |
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Bub Samba Member

Joined: June 10, 2004 Posts: 1336 Location: Central Washington
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Posted: Sun Nov 16, 2025 2:22 pm Post subject: Re: Oil light at idle |
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Put a pressure gauge on it and see what it says...that's the only actual answer.
But, FWIW it's starting to get difficult to build an engine that doesn't do that; it can be wear internally, dirt and buildup, cheap or worn parts, improperly made pressure switch, wiring, etc etc...
I really just ignore an oil light at idle these days if everything else seems fine. You could drain the oil and a VW will still idle until it runs out of gas; I mean it's not great for 'wear' ...but once a new engine is run and every dry part is coated 'any' oil pressure will keep a VW happy at idle.
Generator has nothing to do with it, don't worry about that. Check the pressure to know whats what, _________________
| hitest wrote: |
| Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
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Bobs67vwagen Samba Member
Joined: March 27, 2005 Posts: 950 Location: Eastern north carolina
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Posted: Sun Nov 16, 2025 3:42 pm Post subject: Re: Oil light at idle |
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| One thing to add is you may want to switch to 10w 30 next time you change the oil and see if it makes a difference. I had a 1600 bus years ago that did that from the first time the rebuilt engine was run. I took the pressure valves out and cleaned the passages and tried several different weights of oil. Nothing cured it until I got a new oil pump from cb performance. |
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glutamodo  The Android

Joined: July 13, 2004 Posts: 26634 Location: Douglas, WY
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zerotofifty Samba Member
Joined: December 27, 2003 Posts: 4258
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Posted: Mon Nov 17, 2025 2:50 am Post subject: Re: Oil light at idle |
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To check engine health. adjust the valves. record the before and after values. keep a log book for this, and the amount out of specification between adjustments will be a indicator or trouble.
once valves adjusted, run a compression test record values
place a gage on engine to read oil pressure, record values
the valves are adjusted cold
the compression and oil pressure tests are done hot
a compression test must be run with adjusted valves
the compression test will be good indicator of top end engine health
the oil pressure test will be good indication of bottom end health
also record amount of oil she burns. this can only be done if she is not leaking oil. burning oil is either from leaky rings, or valve guides.
if rings leak, the compression test will be poor, but valve guide leaks will not effect compression test
good luck _________________ Sorry About That Chief.
Give Peace a Chance.
Words to live by. |
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