I just recently took my C3 down off Jack stands for the winter. A brand new noise jus began. (It only does it under load in drive or reverse, so I am assuming that takes the engine out of the question) It s a metallic clicking sounding very much like a piece of sheet metal in a fan. When I increase the revs the noise increases in speed. Any thoughts on the matter?

 

Hi Mako 71,
You don't say whether this occurs while driving or also while the car is standing and you put it in gear?
Did you do any work while it was up on the stands?
Regards,
Alan

 

How long was it up on jack stands???

WHERE did you place these jack stands under the frame or suspension ????

What year is your car and is it a convertible or coupe????

Answering these questions can possibly direct me to tell you where to look due to your car was on jack stands....which can possible make a difference.

It can be just what you think....your fan hitting the shroud.

DUB

 

Hi Dub,
My bet is it's a nice looking 71 black convertible!
Regards,
Alan

 

The Jack stands were under the frame. It was only up for the winter. It has electric fans that had not engaged yet since the engine was not warm enough. It is a convertible.1971 454

 

I did not drive it, as I was afraid it would harm something. I only was pulling it out of the garage to wash it for the first time since last year. It only will do it in reverse or drive. It will increase as I increase the revs. I start it once a month over the winter unless it becomes unbearably cold, an I figure it would cause more harm than good than. I did change the starter at the end of last season as the heat cooked the old one after a rod run. I did run it some last year after the starter change, an heard nothing. It's a back up stater I keep on hand, I don't much care for. It's smaller but has more torque than the very large stock one. But sounds odd when I start it, so I don't much care for it, an don't leave it in usually.

 

Does the noise increase with speed or with revs?

 

Where under the frame?

NOT 'saying' that this is part of your problem showing up. BUT..I can tell you that setting your jack stands under the frame CAN allow stresses to the body and frame can occur for that length of time. Support stands should be under the suspension....even if you have to remove the wheels to do so.

Without you providing an area where the noise is centralized ( front of the engine or at the bell housing)...it is hard to say WHY this is occurring.

IF the car is not moving then it has to do with the rotating crankshaft and those components that can cause it to make noise.

Take the belt(s) off the engine and crank it and see if it is still there.

I have had the spring in the bendix for the starter get weak and allow the bendix of the starter to tap against the flywheel while running...but that is more of a sporadic tapping sound and not keeping perfect time.

Are you SURE it is not an exhaust leak or a spark lug wire making noise due to being worn and arcing on something metal???

YES...he wrote that in the last sentence in the first post.

DUB

 

Yes

 

I put 4 on the sides (two on each side) an one under the crossmember under the engine. Jus high enough so the suspension does not hang but not enough to flat spot the tires. It's difficult to tell as it has to be in gear to hear! It seems as though it's coming from the passenger side near the starter, but I doubt very much I could be lucky enough for it to be the gear on the starter not fully reseating. I plan to check this weekend, as I have to get the car up very high to get under it to check. Already burned my face on the header trying to tell where it's comings from. Any thoughts on cracked flex plate:-(

 

Where in the rear did you place the jack stands??? You only told me where you placed the front ones.

WAIT.... you are adding more to the puzzle. You did not 'say' anything about having to be in gear to get the noise to be able to be heard.

NOW..is it an automatic or manual???

YES...use a hose and put it to your ear carefully and use it like a stethoscope.

DUB

 

Yes. It has to be in drive or reverse it hear the noise. It's an automatic. Two Jack stands on each side. Pass an drivers side. In the back jus before the rear wheel well. The front jus before the front wheel well.

 

THIS DROVE ME NUTS for like a week... in my ralleye cap, a screw came loose, and was jumping around in there. would only really hear it at low speeds, ting tick ting.. WTF!!??..
it would get stuck every once in a while so to me seemed like an intermittent issue.. was thinking the parking breaks.. but nope. I had a screw loose.

 

Ha!!!

 

Sorry, I should have put more emphasis on it. I had read that he posted that it increased with revs, but I wanted to clarify if he actually meant "speed is irrelevant, RPM is the only factor but the car has to be in gear to reproduce the problem" or if "it happens in gear, and as speed increases the noise gets worse".

Some people do confuse speed and RPM.

 

In gear, moving, noise gets faster as car gets faster? What about in gear, foot on the brake so car can't move, give it a little gas, any noise? In gear get movng, shift into nuetral while still moving. Noise same as car movement or with engine rpm?.

If you jack up the rear under the spring support, and chock the front wheels, you can start it and try to narrow down where the noise is coming from. I would have a helper and good health insurance if you do this. I DO NOT suggesting climbing under a car on just a jack. You can get a long length of hose and tape it to a broom handle and use it as a really long stethoscope. Try and listen to tranny, u joints and rear end. You dont have to touch the item, just be close

 

Car in gear. Foot on brake. Give it gas. Noise begins. Does not do it in park. Have not driven it farther than garage to driveway as I assume the noise would be detrimental to the over all car health. Plan to jack tomorrow, an nose around. Jus FYI have Blue Cross insurance

 

Yes. Car has to be in gear to reproduce the noise. But only have the foot on the brake an gave it some gas for the sound to begin, an of course driving it back into the garage it makes it.

 

One again. I would remove the belts that go to the crankshaft and try it. Usually the noise will be there at idle and in PARK if you have a crack in your crankshaft pulley.

Then when you get it up in the air..I would check and see if the bolts for the toque converter are tight. IF they are...then I would remove them and slide the toque converter back a little bit and see if you can see any cracks in the flex plate when you rotate it with a fly-wheel turning tool.

I am also wondering if the transmission mount is BAD..thus causing the transmission to move...but I can not figure out what would cause the tapping of the noise to increase in speed when you rev it up due to the mount being bad.

So the engine has to be under a load to get the noise to show up. So the thought process should be centralized around what changes when the car is under a load and not under a load.

And for what it is worth....if I read what you wrote correctly. When placing the rear jack stands to support your convertible...I would HIGHLY suggest that you DO NOT place them on the flat section of the frame in FRONT of your rear wheels. What this does is allow ALL the weight of the car towards the rear of the car to hang from that fulcrum point and you can do damage to the body. It is best to support it from the suspension.

DUB

 

Tough one. I would do the hose stethoscope trick ti try and isolate it t a small area.

Like dub said, you need to stsrt eliminating things to narrow this down too.
I would take the belts off. Thats a good idea. You fan could be doing something too as the mootr shifts under load
Keep us updated