Topic: Vacuum leak
in Forum: C3 Engines
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OK I new issue has pop up. When I first start the car the driver side head lamp pops up half way then after a few minutes then it goes down. What could be the cause of this.
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Its haunted man, shoot it before it grows. Check out your headlight Actuators and vacuum Actuator relays or maybe your headlight switch past that I don't know. Some of these guys know and they will help you out when they read your thread. Gene
Lifetime MemberLanoka Harbor, NJ - USA
Joined: 12/21/2006
Posts: 828
Vette(s): 1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c
go to electrical forum and read the thread titled headlights winking.
LIFETIME MEMBER #97
THE DYNAMIC DUO
THE DYNAMIC DUO
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Sounds like a vacuum line, headlight switch or actuator going bad. You need to rule each one out. There's a vccuum publication fort C3s available that's really helpful. Can't remember who the author is...
LukesVette 2007-05-03 18:55:52
Hey team!! Anyone know the document I'm thinking of here?
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Not so much your issue, but I have a vacuum leak.
My care was running like 
it might be pulling your engine idol down as well. I have a leak in my container, my mechanic search for days to find out why I was losing pressure.
it might be pulling your engine idol down as well. I have a leak in my container, my mechanic search for days to find out why I was losing pressure.We replaced all of the emission stuff, valves, hoses etc. He finally ran a smoke machine and found a small hole in the unit up front.
Up by the break fluid container the hose runs to the unit, he cut the hose and put a plug in form me (temporary, did not feel like repairing or replacing the unit) 
I rarely drive the car at night, but if I need too, I just pull the plug and connect the hose back. Works like a charm, and the car runs a whole lot cleaner.
Lifetime MemberDeBerry, TX - USA
Joined: 2/27/2002
Posts: 1006
Vette(s): 1971 383 Stroker- mille miglia red...5 speed
[QUOTE=LukesVette]Sounds like a vacuum line, headlight switch or actuator going bad. You need to rule each one out. There's a vccuum publication fort C3s available that's really helpful. Can't remember who the author is...
Hey team!! Anyone know the document I'm thinking of here?
[/QUOTE]
'The 1968-1982 Corvette Headlight And Wiper Door Vacuum Systems' by Chris Prow, aka 'Proracr'? Probably have to e-mail him. According to Joel, he doesn't frequent C3VR much anymore. It is a good vacuum troubleshooting guide. http://www.vettevacuum.com/71_coupe.htm 
I know the voices aren't real, but they have some pretty cool ideas... 
Lifetime MemberLanoka Harbor, NJ - USA
Joined: 12/21/2006
Posts: 828
Vette(s): 1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c
a complete troubleshooting guide is at www.corvette-101.com. covers
checking out the whole headlight vacuum system. it is easy to follow
and best of all its free.
LIFETIME MEMBER #97
THE DYNAMIC DUO
THE DYNAMIC DUO
my headlights were very lazy, i replaced both relays, check valve, filter and override switch now when i start the car both headlights open then close?????? i will be watching for any suggestions since your problem is similar to mine.
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