Okay, so I have:
Headlights that don't pop up anymore, does a vacuum leak sound like a prudent problem?
A hesitation while driving. Feels like the fuel filter may be clogged. I had this show up in my Avanti and it feels very similar. Could it be the clutch slipping and grabbing?
A bad metallic scraping sound when I'm hard in the gas. Could this be the flex fan coming in contact with the metallic shroud due to a bad motor or tranny mount? Bad clutch or flywheel units?
A rear end *clunk* or *thud* feel every now and then. Positraction unit going bad? &
The shift lever (4 sp. manual) shakes and vibrates more than what I believe is acceptable. That's what lead me to say maybe a tranny mount was bad in my prior phrase.

So, what kinds of things are common on C3s to make these symptoms show themselves? What should I look for? Repair? Replace? I know I need to look at the rear end anyway, and was in fact looking to install lower numerical rear gears to get some gas mileage out of the car. Ripping someone off the line is great with 3.70s, but I am in a financial situation where I want to save gas money and pour more money (when I can) into fixing the car and making it a driver (then come the upgrades :D )


[Modified by 1969Vette350, 10:36 PM 8/7/2002]

 

Sounds like time to prioritize. I don't see any particular safety issues, so maybe money and ease of diagnosis is next.
The scraping sound when accelerating might be easy to diagnose by visual inspection near fan. Shroud could be low or motor mounts weak.
The headlites not coming up sounds like vacuum, which could also cause the hesitation. Try a vacuum gauge. Fuel filters change easily and cheaply. Or tune-up.
The rear end clunk could be a u joint or a whole new rear end...the u joint is cheaper and easier to check. I heve never ventured into differentials, but would have to take it to a shop for easy diagnosis.
Shift lever looseness is probably just the hardware around it. It gets used a lot.
Anyway good luck and if things get expensive and you need some cash, let me know...
:blueangel:

 

Dude, do you have a money tree or something? I don't have to do any of those "presidential favors" for assistance do I? I see you're fairly local, are you a glutton for pain? (read: working on C3s) Yeah, I need to do a lot to her, and I'd really like to make it to Hot Summer Nights in Danville, CA tomorrow (8/8.) Unless the hesitation is in fact the fuel filter which I'll replace before I go, I think I'll have to put more time, energy and money into her and bring her up for the last one (8/22.)

 

All corvette owners have money trees. Without one, a covette would simply be a driveway ornament. :lol: :lol:

 

There are vacuum diagnostic booklets, diagrams, and info available. I believe there's info on the corvettefaq.com site, but I haven't looked. If it's both lights (and they both stopped working at the same time), that's probably a good thing 'cause it should narrow down the problem to just a single point of failure for the two, like the light switch (I was pleased to find out I didn't have to completely remove the driver's dash on my '77 to replace the switch).

Don't know about the metal sound :confused:

The hesitation could be caused by lots of things. Changing the filters and even doing a tune-up is a good idea if it hasn't been done for a while. It could be a timing problem. But, there's probably a good chance it's a carb problem. There are lots of people here who can help you out with that.

I'd get the differential fluid changed and make sure they use the GM posi-additive. I had a "clunk" in the rear around turns every now & then and a change of fluid stopped that.

Good Luck.

 

Looks like you have good ideas of where to start looking to solve the problems.
The clunk from the rear...
If it does it when you put it in gear... most likely a U-joint.
If it does it mainly when you decelerate quickly... most likely the front carrier mount.
If it does it while cornering ... I'd suspect the rear end itself.

Shift lever...
I'd try tightening the two bolts that hold it on to it's bracket first. Mine bolts to a bracket rather than the tranny so I doubt the mount would cause this.


[Modified by lbell101, 9:02 AM 8/8/2002]

 

It's possible you have a Hurst shifter in there. They are mounted directly to the tranny and shake a lot.

AC

 

Thanks for the hints guys, I replaced the fuel filter (the one by the engine) and took her for a test drive earlier. I easily went double the distance I went last night and there was no sign of hesitation that I could feel.

The clunking noise that I've heard, and even felt, is mostly when I'm accelerating away slowly, while turning (getting off a freeway, coming to a stop light, and slowly making a turn onto city streets for example.) I've heard about changing the fluid in the rear end and that's my next approach. As stated in my first post I would like to get my hands on a set of 3.08 rear gears anyway, so maybe the clunking sound prioritizes the change to "soon" instead of "in the near future."

I've just replaced the carburetor and gotten it itself tuned, I do need a tune-up and that's coming very soon. My coil just *looks* like it sucks so that's another part I want to replace.

The headlights are screwed as a pair. The both don't go up nor do they go down. I'm fairly certain it's just one small thing that is going to hide from me for a long time though. My friend did suggest vacuum supplement booklets, his brother has a '66 T-Bird and found one for that car. Hopefully I can get my hands on one for the 'shark body' Vettes and track down that problem.

Stevo, I didn't mean to scare you away :D

I think I need a money tree soon :chevy :cheers:

If there are any Bay Area or East Bay Corvette folks at Hot Summer Nights tonight or on 8/22 in Danville, CA I'll probably see you. I'll have my camera in hand (or around my neck) and my "Chrome Bumpers" Stingray shirt on.

 

Fresh oil and posi additive in the rear end will probably make the slow speed clunk disappear.

You need 3.08s? I have 3.08s and want something a little more preformance oriented.

IM me and let's talk.

 

Alrighty then... who knows much about vacuum lines? I swapped the thermostat that was in my car from a 195* F. to a 180* F. I did this because the outlet gasket had failed anyway and I decided to check if the thermostat was any good while I was in there poking and prodding. A few minutes later and the old "boiling water" test in the kitchen proved the old thermostat would not open. I was told the car could take one of three different temperatures: low, medium and high. I went with medium and the guy gave me the part number and the temperature rating. Does 180* F. sound like the mid-temp. option to any of you? Would going to a lower temperature thermostat affect the vacuum system?

Coming home from Hot Summer Nights on Thursday night/Friday morning yielded a very interesting occurance. The car hesitated, hesitated, hiccuped, hesitated and died. She started up again but it was very rough the first two times, like she was starving for air. I got going again and was able to make it home with no more drama, but I was left thinking about that. . . What happened there? This was on the freeway in 4th gear between 2500-3000 RPM (3.70 rear gears and 295/50-15). I've had bad hesitations before, but this was the first time the car shut off because of it. :confused:

Thanks for the help so far everyone. I've replaced the above said thermostat/gasket and the fuel filter. The headlights still don't come up (or go down) and my idle is way high at 1500-1700 RPM.


[Modified by 1969Vette350, 1:02 AM 8/11/2002]

 

Daddy, i thought corvettes were to push out of the garage, wash and wax then push back in to the garage.

 

LOL, alright, fair enough :cheers: :chevy

 

Headlight problem is almost definitely a vacuum leak. Problem with these cars is that a lot of systems run of vacuum.

For example, I once had a '77 with the lazy headlight problem. One day, I was working in the center console and found some vacuum lines disconnected from the heater control. Reconnected them and the headlights worked again. The heater control system uses vacuum to control which vents it uses.

All I can suggest is make sure that every vacuum line is plugged in at both ends and then check their condition.

Concur with the above on the rear end fluid. Cheap first try. In fact, I have to find some time to do mine. :smash:

 

As for your phrase "A bad metallic scraping sound when I'm hard in the gas", I ran into this same problem with a 396 Impala way back in the 70's when I rebuilt the engine. It seems that I put the trans dust cover back on the wrong way and when the engine torques from the acceleration, the flywheel contacts the dust cover. I can't remember how I fixed it exactly, except that I probably removed it and re-installed it to take care of the problem.

There are 4 bolts that hold the dust cover on the bottom third of the front of the trans. As an experiment you might want to temporarily remove the dust cover and try being hard on it and see if that makes the noise go away.

 

I shall check that when I have daylight :D , thank you for the tip.