dilbertquad7

Everytime I start me 85, I can hear a noise that almost sounds like air bubbles in a tube, but I don't think it has anything to do with fluids because you can only hear it inside the car or directly underneath the car. Also, because the sound slighty changes when I put the car in gear. Here's the thing, when I start it, sometimes I will hear the sound and I will notice that my RPM synchronizes with it. Also, whenever I have just started it, and the choke is out so that the RPM is around 1500, the sound will become somewhat violent and the RPM will steadily drop until the car stalls out. Also, when I first start driving, the noise will be there and I can feel very unsteady acceleration that coincides with the noise. As in, I will be giving the car gas and the noise will get louder as my RPM drops and my car rocks a bit.

The sound will also occur whenever my car is tilted to the right, aka, during hard left turns or on uneven roads. However, once the car has warmed up and is on level ground, the noise dissapears.

Is this because of some loose mechanical item, could it be my throw-out bearing of my clutch?

Any insight would be helpful because it concerns me that the sound is related to the RPM...

Thanks

84stock

iTrader: (5)

look for a loose heat shield by the catalytic converter

dilbertquad7

I checked around the area and all the heat shields are secured. But would a loose heat shield actually affect my RPM? I think whatever the problem is, it's connected to the engine through the belts. Any ideas?

DivinDriver

iTrader: (15)

Sounds like an air/ fuel-related misfire, to me... particularly the bit about hard turns making a difference.

Have you checked fuel level in your float bowls?

gsl-se addict

iTrader: (3)

Can you better locate the source of the noise? The noise is always there (moving or not)?

Just a guess, but I would say a hole in the pickup tube or in the line before the fuel pump may cause this. This would suck air in with the fuel (might be the source of the sound) and the delivery of fuel to the carb would be starved (just like when you are almost out of gas).

How much fuel is in the tank? How long has it done this for? Does it do it if the tank is completely full?

It sounds like a fuel problem to me based on what you have said so far. Could be more on the carb end of things or back at the tank (pickup issue).

t_g_farrell

iTrader: (1)

I agree with Kent, sounds like a fuel tank/pump issue. Check you filter and then do a flow test to make sure gas is flowing good to the carb.

DivinDriver

iTrader: (15)

Sucking air into the pre-pump line wouldn't matter once the fuel gets in the bowls, would it? Unless you were sucking so much air your bowl level couldn't keep up with the jets at 1500rpm, which would have to be a helluva air leak.

Seems like a leak that big would spew fuel once you shut down.

It is possible, though.

gsl-se addict

iTrader: (3)

If the hole was in the pickup, tube, no fuel would leak out. Also, it kills fuels flow a lot more than you would think. Think of trying to use a straw that has a small pinhole in it. The top parts of the tank are also the most likely parts to rust as they are more often exposed to air.

So it is a combination of the pump having a hard time pulling the fuel up..then once air is in the pump, the pump has a hard time due to the compressibility of the air. Inconsistant flow and pressure could result.

Just an idea. We need more info from the OP to better isolate the issue.

DivinDriver

iTrader: (15)

This one's fun, because, essentially, we can both be right... If fuel flow is that impacted, float bowl levels will not be able to keep up with demand. Volume/pressure test would be next, which would rule out the carb if it's a pickup problem.

gsl-se addict

iTrader: (3)

Yep. As I said in one of my previous posts, it sounds like a fuel issue. Either at the carb end or at the pickup. Especially since it does it in turns, etc. Easiest test would be to fill the gas tank completely. If the problem goes away, the hole is in the pickup. If not, then time to test volume/pressure and check level in the sight glasses.

The other possibility is some kind of mechanical noise (suspension for instance), but we need to know more from the OP and then we can start crossing things off. It is always hard to figure out what the noise might be when we can't even hear it.

jinxed4dub

iTrader: (7)

are your headlights blood shot? jk sorry couldn't resist

dilbertquad7

I doubt it has to do with the fuel lines. Even with my tank full it does it, and when I'm driving on level ground or turning right there is no sound.

As for locating it better... I'm pretty sure it's either underneath my shifter, or right underneath my dashboard. From what I've been hearing and how it feels, I think it has nothing to do with fluids, but something along the lines of a worn throw-out bearing or maybe some other messed up joint.

I say throw-out bearing on the clutch because when I push the clutch in, the sound does change... but it doesn't go away.

I've checked my fluid levels and everything is fine, there's no leaks and I doubt there would be any holes in the lines.

On a side note, I did get in a front end which did force my car's body slightly out of shape. We pulled it back into shape and replaced the radiator with a used radiator (we flushed it out several times). We also had replaced the water pump for the radiator before the accident and there was no noise back then. Could it be that the accident messed something up?

(Sorry, just thought about it or I would have given that information sooner).

jinxed4dub

iTrader: (7)

did you burb the coolent? if you put new fluid into the rad it pushes the air back twards your heater core causing a air bubble. it could be changing with the clutch due to your waterpump slowing down. theres several ways to get rid of the air bubble. the easyest is to get a flush and fill kit. another is to park on a steep incline and crack open the radiator cap (wait till it cools) and fill it back up to full. good luck.

gsl-se addict

iTrader: (3)

We need you to do some tests:

- check with car parked. Try with the trans in neutral (clutch out and in). Try in different gears (clutch in). Does it make the noise? Does the sound go away when the engine is warm (still parked)? Does the sound change with RPM?

- If it only does it while driving, also try putting in neutral and/or putting clutch in. Does the noise change with speeding up/slowing down? Does it change with gearing?

We need more info. We can't see it and can't hear it, so we need to know exactly under what conidtions it does this. I can't think of any mechanical rubbing that would go away with the engine warm. The noise related to turning or not could be suspension or wheel rubbing or something like that due to the crash. If it makes the sound when the car is not moving, we can eliminate quite a few things.

The more info you give, the better we can help.

dilbertquad7

Alright, sorry for being away for so long, I'll check all the stuff you suggested.

Thanks for the methods gsl-se addict, sorry if I'm being vague, I'm pretty clueless about these strange noises.

gsl-se addict

iTrader: (3)

Noises are tricky..especially over the 'net. Best bet to to track down exactly when the noises happen and try to locate where they are coming from (this can be hard, though). Then we can try to come up with what it might be.

dilbertquad7

Okay, so I played around with the car while it was warm yesterday. Here's a list of all the things seperated into categories

No noise when:
-car is parked while engine is warm
-shifting gears while engine is warm
-parked on steep incline while engine is warm


Noise does occur when:
-starter is turning, noise occurs and corresponds with the rpm
-after engine catches, with choke pushing rpm to 1500
-seems to occur whenever on a bumpy road (need to investigate this more) even when warm

Noise changes when:
-clutch is pushed in while engine not warm, changes to a more supressed sound

Summary (lol... there are things missing)
When the car just starts, it will be at a lower rpm, but after just coasting, the rpm rises about 500, (1.5k to 2k) At around 2k, the sound disappears and does not come back even if I manually push the choke in to lower it back to 1.5k (Need to try that again to verify).

At this point, I'm not sure if the sound really occurs because the car leans to the right or just because I was on a bumpy road at the time. Even when I think it occured, it only occured while on the bumpy section then went away.

Also, I listened more closely to the sound, and it seems to be coming from behind the dash panel (the place where climate control and stereo faceplate are?) Anyways, it comes from in front of the shifter.

Thanks to all of you who are still trying to help. Any help is much appreciated.

DivinDriver

iTrader: (15)

Air gurgling through the heater core? Maybe a pinhole leak is sucking air in there during cooldown, until engine heat & fulid flow moves it out?

See if the noise varies based on the position of the temperature control lever.

gsl-se addict

iTrader: (3)

Could be like jinxed said and that there is air in the system since you said it did not do it before the accident (and before the rad replacement). Although, it shouldn't change with clutch position if this was the case.

Engine temperature look okay? Does the heater seem to work?

Depending on when the accident happend, maybe he hasn't used the heater at all and maybe forgot to crank up the heater while burping the air out of the system. It can certainly be a good place to trap air in the coolant system.

dilbertquad7

Okay, I'm thinking about flushing the coolant, but I know that when my dad and I flushed the system and refilled it, we made sure to open up the heating valves by turning the heater on.

Honestly, I'm on the point of giving up and running the engine without caps on to watch fluid levels or something...

But there's more about noises.
-There seems to be two types of noises in general. One is faint, just a continuous sound of... I guess, a mix between air bubbles in water and the grinding of a non-metal material. With this sound, there is no shaking feelings. The other noise is more violent, which sounds like something shaking, almost as if it's a metal rod trying to break itself and getting caught... (I guess like something just hitting something else? but it's too muffled a sound for it to be metal on metal) With this second sound, I can feel my floor board shake, but only around my feet. It's this sound that coincides with unsteady rpm.
(Sorry, I'm trying my best to describe it, but I've never heard anything exactely like it)
-When I cut the engine off, warm or cold, it will make the noise, for a second before the tachometer finally hits 0 rpm, except it's violent enough to shake the whole car.
-When I am idling, and the idle becomes unsteady (drops a little then goes back up) when the rpm is low, the violent noise is there, but only momentarily.

-Then, when I move my steering wheel about 40 or so degrees to the left, I can hear the first noise (soft steady noise) until I straighten my wheel again. This happens only when I am moving (anyspeed as far as I know) (I'll check that again to make sure). Another thing is that, when I was going up a hill and turning left, while giving gas in 4th gear, the violent noise suddenly appeared then disappeared after I straightened up.

- Now, about turning right. I can't get it to happen when turning right...
-I found out that bumps definitely affect the sound. When I hit a bump, I can momentarily hear the violent noise. It generally goes away right after I get back on a smooth road (Can't tell because the road generally still has bumps after a bad bump)

Okay, so that's all I have... if you all are ready to give up, I'm done... I'm just going to end up checking everything.

gsl-se addict

iTrader: (3)

The whole turning thing makes it sound like a tire rubbing or something like that (maybe fender or something is still bent from the accident).

The other noise (when shutting off the car or accelerating uphill): maybe bad motor mounts or bent rad support or something allowing the fan to contact the rad or the shroud?? Although, it would be more likely when warm when the fan is fully engaged..hmmm.

If the sound was just under heavy load (acceleration or uphill), then I would also wonder about detonation. Is your ignition timing set correctly?

Is it possible to make a video of it so we can see/hear what is going on? That might help.

I would try to jack up the front end and crank the steering to each side and spin both front tires. Look for rubbing or anything unusual. Look inside the fender wells and see if they are bend or if there is something that the tire/wheel/brake rotor might come in contact with on bumpy roads or turning left. Also, grab each wheel and try to shake it (in/out) to see if there is play in your wheel bearings. A bad wheel bearing can make all kinds of noise, but it would only happen when the car is moving.

Maybe you can have a friend or something look the car over while it is making the sounds (when the car is not moving). They might be able to hear where it is coming from or notice engine vibrations and something rubbing (like the fan).

How close are you to Atlanta? I might be down that way in July or August and could maybe take a look at it.

dilbertquad7

I'll check the steering issue, and I'll try to make a video or at least a recording of the sound.

My dad and my brother and I have all tried to pinpoint the sound. But the sound is unhearable in the engine area outside the car, and is extremely faint from the bottom of the car. Basically, the only place you can actually hear the sound is from behind the climate control panel and stereo faceplate area. From feeling the vibrations in the floor board, it seems like it's coming from behind the actual engine. Anyone know everything that could get loose behind the engine?

That's the best that we can pinpoint the sound.

Also, it doesn't make the sound under heavy loads, I can accelerate and go up mountains without hearing the sound. It only happened when I was turning as well. Maybe turning exacerbates the situation?

I'm pretty far from Atlanta. More than several hour drive so you don't have to come down. Thanks for the offer though. And thanks for the suggestions and help.