2003 Buick Rendezvous machine gun start, clicking under hood


#1

Hello, my truck has this rapid machine gun type start, but not always. It always starts though. I had the alternator tested at O’Reilly auto. They said it was good. I have also been trying to see if there is a possible relation with my clicking sound. I guess it might be more of a steady tapping. I thought it was possibly a lifter. My neighbor that works at one of the quickie lubes said he would take a look. He listened with a screw driver and said he did not here the clicking/tapping sound from the engine. I showed him how when you accelerate on the gas it gets faster and louder. He said it sounded like it was coming from one of the pulleys. There is no kind of squeaking though, just a loud obnoxious tapping noise. He said that he thought it could be a bearing.I am just trying to think if there is still some kind of alternator relation, because also at times going down the road I notice that the lights on my dash flicker a bit. From looking at all of the pulleys, they all look pretty steady. Although, the crankshaft pulley on the bottom does look like it has just a little wobble. We did not have a long enough screwdriver to listen for the tapping in the pulleys. Also, the serpentine belt is good on it. I thank you for any help. Chad


#2

A short piece of garden hose works much better. You don’t have to make contact like you do with a screwdriver. Just be careful around the pulleys.


#3

Hello, thanks for the reply. I’ll try to check it like that this weekend.


#4

@Chad1317
"Although, the crankshaft pulley on the bottom does look like it has just a little wobble."

I Suspect It Could Be A Bad Harmonic Balancer (That Crankshaft Pulley With A “Wobble”).
They are designed with rubber between the steel hub and steel pulley and sometimes the rubber will separate and cause the pulley to wobble, slip, shake engine, or make noise, or a combination of these symptoms.

I wouldn’t continue to drive the vehicle and wait to get it verified and replaced if needed. Collateral damage could result.
CSA


#5

Hello, thanks for the reply. Yeah, I was thinking that too, because the other ones don’t seem to have any play. I am hoping that it could also be some of the issue with my machine gun-like starting sometimes, maybe it is slowing alternator some. I am definitely going to get it checked this weekend. I am in-between jobs at the moment, so it couldn’t have been a worse time. I have to wait til Friday and I have just been driving moderately slow.


#6

@Chad1317
Take A Few Minutes To Read Article From 1A Auto Discussing The Harmonic Balancer. You’ll See Some Of Your Symptoms Mentioned.
link:

http://www.1aauto.com/harmonic-balancer/c/82
CSA


#7

When the phrase “machine gun” sound is invoked here, my first suspicion is some kind of exhaust system problem. That can sound just like a machine gun. And it can come and go as parts expand and contract due to thermal differences. If not that, next would be an intake valve or timing problem allowing backfires into the intake manifold. Why do you think the alternator is involved? Usually pulley and accessory sounds, even if something is wrong, doesn’t sound like much like a machine gun being fired. The sound of gasoline exploding however sounds very much like a machine gun.


#8

I suggest you check the bearings in the belt tension pulley to see if they may be going out. The vehicle is at the right age for that to happen.


#9

I suggest that the noise is the starter solenoid making the loud machine gun noise. The flickering lights suggest that the alternator is either is bad or the connections are bad. The connections could be bad at the battery or the ground. The battery could also be bad. The belt could be slipping at the harmonic balancer, but I suspect it’s alternator. This all can be tested at the local auto parts store.


#10

Hello guys, thanks for the replies. Yeah, the starting doesn’t do that noise all the time. It actually hasn’t done it in a few days. It just has that repetitive clack-clack type sound turning over when it does. It seemed like it was a starter/alternator issue. Then I just was trying to figure if the tapping possibly was maybe the alternator pulley. I saw the comparison somewhere like its a card in a bicycle spoke sound and gets faster and a little louder as you give it gas. I thought sure that it was a lifter sound, but my neighbor said he did not hear it coming from the engine when he listened with a screwdriver. He said it sounds more towards the pulleys. I looked at my dash a lot today and it didn’t seem to be dimming at all either, but my tapping under the hood doesn’t go away. It’s not a loud when it’s just idling though. I am going tohave a mechanic look at it at his shop this weekend. I am not much mechanically inclined and haven’t had the money switching over to a new job. You guys are a big help and I will keep posting and try to get this figured out.


#11

Also, my AC seems to work fine, but when I popped the hood trying to listen for that pulley, it makes kind of squealing sound when I turn it on. I feel like as far as the tapping under the hood goes, it started a few weeks ago after a routine oil change. I used the same oil Valvoline semi-synthetic though and a purolator classic filter. So, that’s why I thought that might have been a lifter issue till my neighbor said he did not hear the tapping near the valve cover, but more near the pulleys.


#12

Squealing when ac is turned on is likely a belt issue , belt too loose or worn . Tapping noises are often in the valve train . Your neighbor could be wrong . I recently replaced an engine in one of my vehicles . I had loosened the one bolt that held the serpentine belt tensioner to the engine block . The tensioner is spring loaded & that bolt didn’t need loosened .
During the engine installation process I neglected to tighten that bolt . After starting the engine I had a tapping noise that wasn’t present in the engine in the vehicle I removed it from . I hadn’t loosened that bolt much but after doing a lot of checking I found it wasn’t tight . I tightened it & the tapping noise was gone .
Your noise could have something to do with a pulley or it could be a lifter or something else . Engine noises have a way of traveling & sometimes are hard to pinpoint . How hard would it be to remove the belt / belts & start the engine to see if the noise is still there or not ?


#13

Yeah Sloepoke I am beginning to think that my neighbor is wrong. I listened real good again on my lunch break and I feel like it is coming from the back of the engine it sounds like to me. I don’t feel mechanically inclined enough to tear into things myself. I just know that I think it is odd that this happened about roughly 2 weeks after an oil change. I am considering doing an oil change again this weekend because it would be cheap. I am still going to have it looked at though by a mechanic. I am wandering if it was possible something might have broken up on the oil change. I had also forgot I originally had used a Fram extraguard filter(the orange one with the black grip on top). Well, a buddy at work that is a kind of back yard mechanic said he had 2 family members that lost a lot of oil pressure with Fram filters. I talked to a tech at O’Reilly and he said he had been using Fram filters for years. Nevertheless, I had switched it out with a Purolator classic filter. The thing I had remembered was the Fram filter said it had detergents that release in the filter and also the Valvoline maxlife semi-synthetic oil I use has detergents as well. I am just starting to wander if they caused something with the hydraulic lifters and an oil change this weekend might do good.


#14

Certainly wouldn’t hurt to do an oil change . I once did an oil & filter change & right away I began noticing that it was taking a long time for the oil light to go off on engine start up . I changed the filter & everything was back to normal . Defective filter I guess , it was a Fram . I have read that the quality of Fram filters has really suffered & I no longer use them .


#15

The first thing I would do, is to loosen the belt tentioner enough that you can spin each pulley by hand. You may hear or feel a roughness in one of those items.
Also, if you spilled any oil on that belt when you did the oil change…that could be causing the squealing. A new belt would be in order because you will never get the oil out.

At that time you can also give the alternator a spin to check the bearings in that.

I think you have two separate issues.

The flickering lights would have nothing to do with a pulley bearing going bad, but rather a poor connection at the 1. battery, 2. a body ground, or the 3. larger wire that attaches to the alternator. That wire carries the current to charge the battery.

I would remove both battery terminals at the battery and then follow the wires…one to the starter…the other (the ground) to where it attaches to the engine. Remove those ends and wire brush the mounting area well along with the terminal ends and re-tighten them.
Clean up the battery posts with the wire brush and the insides of the battery clamps, and re-install both.

Yosemite


#16

Well, I went to see a mechanic today and he said it sounded like the tapping was coming from the back portion of the engine behind it. He was asking me all about the oil. I said it happened a few weeks after the oil change, he said that he would have used 10w40 and some Lucas stabilizer. I told him that I used 5w30 that is labeled on it, the Valvoline semi-synthetic and Lucas together. He thought it was too thin. He said I should try the change first and see. If not,he said something about possibly a rod and threading. I would have to leave it, so he could open the engine up. That’s a tough one right now not being able to afford a rent-a-car.