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"grinding" noise when started - Suspension Air Pump

M

mikeblank216

Full Member
Joined
Feb 8, 2014
Messages
26
Location
Cleveland, OH
New to the forums, Not exactly sure where to post this due to not knowing what the problem is.  When I start the Av it will make a noise, which seems like it is coming from the rear end, that sounds almost grind like or self adjustment.  The service suspension will turn 1 out of 4 start ups through a normal day.  Have done some searching on the forums and internet and can't seem to find too much info.  Is the truck trying to "level" itself out?  Please give any feedback you may have.  Thanks in advance! :help:
 
Give us a idea what year and model do you have.
 
My guess that is the air pump for the suspension. You may have a problem with one of the shocks.
 
The air compressor for your shocks is mounted to the truck frame right behind the driver's side rear tire.

See if that is where your sound is coming from.
 
Just tested it out and it's definitely where you suggested. Do you think it's the compressor then? i got an extended warranty in case anything like this happened...
 
Here is a pretty long thread on the forum with a lot of good discussion and pictures:

http://chevyavalanchefanclub.com/cafcna/index.php/topic,131766.0.html

There are other threads, as well.
 
thanks EXT, will be reading through all of that before I contact the dealer to help explain the situation better.  I appreciate the feedback and guidance! 
 
Those pumps are louder when cold.  They often kick in after start up to reset the height due to bleed down while parked. Check to see if the bags are firm... compare one side to the other. You could have a leak in a bag, line, sensor or pump.
 
Thanks Line, I will check it out.  This noise is pretty loud.  I just came back in from getting under the truck after turning it on to reinforce where the noise is coming from and it is definitely where EXT4ME suggested. I have read that you do normally hear it kick on while standing next to it, but should not really hear it inside the car.  Which in my case in untrue, I hear it kick on with doors closed, daughter fussing in the back and radio turned up fairly loudly.  Although when I did just start it of course "service suspension" did not pop up on the DIC.  Like I said in my original post the DIC will only prompt service about 1 out of 4 starts.  Called the dealer over an hour ago and got the "can I call you back, I need to speak with a used cars manager".  Ready to call back and start yelling!
 
so i called and got a bit of a run around that lead to a call back 5 mins later.  what they told me (which i need to research and look into) is that the previous owner replaced the front shocks with normal shocks rather than autoride which is triggering the service suspension.  would this cause the compressor to become louder?  just trying to make sure they're not giving me the typical used cars-man schtick.
 
I doubt having non-auto-ride shocks is going to cause the compressor to be any louder.

True auto-ride shocks, front and rear, will have an electrical connection to allow the shocks and computer to work together.

Regular old shocks will not have this connection.

You might be getting the error message because you do not have the auto-ride shocks, OR if the air portion part of the rear shocks is bleeding down too far and your old, weakening air pump is not able to pump those shocks up in a certain amount of time, perhaps a code is generated to let you know something is amiss.

Under normal conditions, I think you should be able to expect your pump to kick on for a few seconds each time the truck has sat idle for a period of time, like maybe overnight, but not just while you went inside a store to grab a soda pop.

If the shocks are holding air as they should, you might get the pump to run first thing in the morning and maybe not for any more during the day.

I bet if it takes too long for the shocks to pump up and the truck's computer takes note of the extended amount of time, it most likely will think something is wrong and toss you a code.

That is probably why you see the code sometimes and not others.

My money is on you having some leaky air shocks and a pump that is on it's way out.

Keep us posted.
 
again, i really appreciate the feedback.  i am unfortunately not as car savvy as some  ???, which is embarrassing enough , so the wisdom is greatly appreciated.  i feel like im being a pest with all of this to you guys so sorry if it comes across that way! will keep updated as i try to figure it all out!  thanks again
 
You are not being a pest.

Helping others is a big part of what this group is all about.

I had another thought, if your current shocks are not auto-ride and they do not have the electrical connection, I bet you would be getting the error message all of the time instead of just every once in a while.

I'll put one more dollar on my bet of it being your air shocks/air pump being the root of the problem.
 
SOOOO...my wife and I just ran out to grab some items from the store.  The only thing I put in the bed was dog and cat food, roughly 45 pounds.  Once I started the truck the compressor stayed on while in park and did not turn off until I began to drive.  After dropping the items off at home we went to dinner.  Upon coming home, empty bed, once I parked in the driveway the compressor kicked back on and kept running.....first time it has done THIS!  all other times it has just been on initial start up.  :E:  ???
 
With it being certified, I'd be heading right back to the dealer and telling them to fix the issue. Something is wrong with it.
 
will have to call again, they tried telling me otherwise today when i called to address the situation at first....maybe even a surprise visit
 
Quick question...would an auto shop (pep boys, meineke, firestone, etc) give me an inspection if i called them? I wouldn't want them to repair it, since im under warranty but i have a feeling this dealer is going to try to do what it can to not pay for this. So if i had a mechanic look at the compressor and suspension i would get an answer to give to the dealer.  Other reasoning for this is the distance to the dealer, makes for a long trip with a 1 year old daughter. If one of these place did the inspection, any ideas of cost for a look over ?
 
mikeblank216 said:
Quick question...would an auto shop (pep boys, meineke, firestone, etc) give me an inspection if i called them? I wouldn't want them to repair it, since im under warranty but i have a feeling this dealer is going to try to do what it can to not pay for this. So if i had a mechanic look at the compressor and suspension i would get an answer to give to the dealer.  Other reasoning for this is the distance to the dealer, makes for a long trip with a 1 year old daughter. If one of these place did the inspection, any ideas of cost for a look over ?
Click to expand...
you wuold have to pay them for their time...

 
ygmn said:
you wuold have to pay them for their time...
Click to expand...

This.

And I have found that the people you are trying to convince often could care less about any "proof" you might bring to the table in this manner and summarily dismiss that information.

If you can't get any satisfaction by dealing with the dealer directly, then perhaps discussing your options with an attorney that has reviewed your contract with the dealer might be a possible next step.

Sometimes, a letter from an attorney reminding someone of the terms and conditions of the contract is enough to get them to just go ahead and do what is required of them.

If your contract with the dealer, in the opinion of the attorney, does not give you a leg to stand on, then you will at least know whether or not pursuing action with the dealer will be a waste of your time and efforts.

There are attorney's around here that will review your case for little or nothing and can tell you if you have a case or not.

Just a thought.

Good luck.
 
Don't make a mountain out of a mole hill.  IF you have a dealer that is responsible for proper operation of the vehicle and a warranty exists.....tell them it needs to be fixed because it is broken and shouldn't run that long and that loud.  Stand firm and be prepaired to leave the truck with them for a few days.  If you are not willing to, or it is not worth your time, take it to the local mechanic and pay to have it fixed.  Those are your 2 options.  Unless you want to fix it yourself.  Often an attorney will cost you more time and money then paying the shop to do the repair. Unless you know an attorney who will do it for free.

Before starting the truck you can check and compare the bags to see if they are full.  If one is lower then the other or, both are low (in which case the truck will seem low just looking at it) the bags will need to be replaced.  FYI...replace them in pairs.  A noisy pump is a noisy pump, and would require replacement to eliminate the LOUD noise.  However, most can be heard with the doors shut so, I wouldn't be too concerned unless it is running longer then a minute or two or very loud. Either way, the codes mean something is not as designed.
 
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