Engine Noise

denaliguy

Original poster
Member
Jun 1, 2013
56
Looking for help on this noise I'm getting from behind the radiator. I have no codes flashing or performance issues. Everything is functioning fine, but the engine noise has definitely changed and sounds worse. I drive a 2007 Envoy Denali with 120k miles. Recently changed all fluids at 100k (front/rear diff, trans, radiator, etc.). I also change the oil every 7000 miles. Anytime there is an issue I take care of it immediately. I have had no major issues with the vehicle. I am stumped with this noise though, so on to that.

I first starting noticing it this past Fall. I can only describe it as a "wobble." The way it sounds is like a loose pulley wheel on the belt but everything appears to be tight. The sound is coming from the front of the engine, behind the radiator. There's no ticking noise, the only thing I can think to compare it to is a running paper press. It's a repetitive noise along with the normal engine noise. It's not quite like a piston slapping, but close (just not as much of a "tick" sound). I've had the vehicle for a few years now, so I know it's a new noise. Here's a video of what I'm talking about:

https://www.youtube.com/watch?v=3o1YXFhWrSk&feature=youtu.be

Any thoughts?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Is the water pump bearing wobbly when you wiggle the fan blades? I'd pull belts and confirm the noise stops. Then you have some confidence that's it an external rotating part of the engine and not internal. I'd guess water pump at this point, but the video didn't jump out and say anything to my ears.
 

Robbabob

Member
Dec 10, 2012
1,096
Do you see the idler arm moving or bouncing? It should remain pretty steady with the engine running.
 

denaliguy

Original poster
Member
Jun 1, 2013
56
Everything looks and feels tight, no bouncing. What's throwing me off is that there is no chirping or squealing, which is what everyone describes with bad pulleys or a bad water pump. I'll take the belt off tonight to see if that will help narrow where the "wobble" noise is coming from. Again, there is no movement or physical wobble to the pulleys/belt. Just the noise. I'll update when I get the belt off.
 

denaliguy

Original poster
Member
Jun 1, 2013
56
UPDATE

Here are couple new videos. First shows the engine running with the belts on, over and under view. Sorry for the fan wind in the very beginning, tough to shoot. The sound I'm talking about is pretty obvious in this video. I think it might be the water pump but no leaking antifreeze (might be early stages of it going bad). I'll be taking the belts off this weekend (family arriving tonight for a visit so any work is being put off until they leave).

Second video is me revving the engine showing the sound is not related to acceleration. The engine performs like it normally does. You'll see the idle is normal as well.

https://www.youtube.com/watch?v=25WnpCJNr98

https://www.youtube.com/watch?v=aFWWPeUXmNc&feature=youtu.be
 

denaliguy

Original poster
Member
Jun 1, 2013
56
Snuck away from the family for a few minutes and pulled timing belt. Sure enough no noise on start up. Engine sounded smooth with no belt. Tried to wiggle and move each pulley and the only one to move was the water pump (though it was slight). No major side to side but it did wiggle a little. I'm guessing it's early in failing. Debating on tackling this myself or paying more than I need to have someone else do it. Hmmmm....
 

dmanns67

Member
Apr 3, 2013
32,979
Ohio
When my water pump failed, not too long ago, I had a loud squealing noise and coolant being thrown all over the front of the engine bay. Not much trouble shooting to do.

Rock Auto has the AC Delco water pump for right around $100. Dealership wanted $240 for the same part. If your mechanic is cool with it, I would recommend buying your parts from Rock Auto and saving a lot of cash. If you Google "rockauto.com coupon code" you will find a 5% of your order coupon code as well.
 

denaliguy

Original poster
Member
Jun 1, 2013
56
I called one dealer just to get an idea of what they would want. $340 for the pump and $575 for labor. Unreal. I'm calling a couple shops to see who's comfortable installing a part I buy. Just moved to Kansas City 10 months ago and haven't needed/wanted a mechanic yet so don't know anybody. I'll probably just end up doing it myself, just gotta find time (that's the issue).
 

dmanns67

Member
Apr 3, 2013
32,979
Ohio
The only issue you might have is that if your part fails that you purchased from Rock Auto, the shop that installs might not cover the warranty for the part unless it was an installation issue/error. The shop would still be making money off of the labor cost though, so I doubt many would turn you away. I am sure the dealership might though.
 

denaliguy

Original poster
Member
Jun 1, 2013
56
SOLVED

It was my water pump. Bearings were in the early stages of failing and making the wobble/knocking noise. It did not lead to any leaks (yet) and didn't cause the belt to squeal (yet) so that's what threw me off. Picked up a lifetime warranty water pump and lifetime belts from Autozone and did the job Sunday. Really took my time and cleaned everything thoroughly while in there. Total time was 3 hours to replace. She fired up and was quiet from the start. Drove it around last night and to work this morning with all gauges reading fine and coolant levels normal.

Total cost $240 (including tax). $158 for lifetime water pump, $32 for lifetime serpentine belt, $15 for lifetime A/C belt, and $14 for gallon of Dex Cool. Dealer wanted $1200 to do pump and belts.

If anyone has questions about the job let me know.
 
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C-ya

Member
Aug 24, 2012
1,098
denaliguy said:
If anyone has questions about the job let me know.

You new at this or something?? :rotfl: You should know by now pics are always appreciated. What did you move to get to it? Any tough to get to fasteners?

Come on, man! Give us something to look at while we're at work! You know guys don't read, but pretty pics grab our short attention span every time.



All kidding aside, a few notes may help someone out. I heard so much negativity about changing the spark plugs in the 5.3 that when I did mine, I took pics and wrote about how I did it. May help just one person, and if so, it was worth it.

Glad you got yours repaired, and saved some coin. That's why I don't mind getting a little dirty. $960 (in your case) can buy a lot of soap and new clothes! (Or beer.)
 

denaliguy

Original poster
Member
Jun 1, 2013
56
You're absolutely right C-ya, I've taken more from this forum then I've given. I'm working on a write-up now with some pics. Unfortunately I'm in a 6 week stretch of no free weekends. I only had this past Sunday open because my family decided to leave a day early. Weddings, work conferences, house work, visitors, etc. have eaten up all my time. Excuses aside, I will get a write-up, with pics, in here.

The only issue I had was getting the fan off the water pump. They say you can knock it loose with a fan clutch wrench and hitting it with a hammer but the water pump pulley wheel turned every time I hit it (even with the belt on) so nothing came loose. I ended up needing a spanner wrench to hold the pulley wheel in place and then turning the nut with the fan clutch wrench. O'reilly's came through for me on the spanner wrench since they are not easy to find in stores. They opened a new one for me and let me use it as a loaner ($50 to purchase). The spanner wrench has two teeth that fit in pre-drilled holes on the pulley wheel. It allows you to hold it in place so you can get enough torque to turn the fan nut loose.

You'll want to be careful when taking out the fan assembly (shroud, etc.). It's all one piece that covers the entire radiator and you have to force it a little. If you force too much you can poke a hole in the radiator. Once the fan assembly was out it really opens up the front end to get in and replace the water pump.

I'll add pics later, but for now here are the steps you have to take (if you're ok with reading :tongue:):

1. Pull bottom radiator hose and drain coolant into bucket. Leave bucket there for entire project, coolant occasionally leaks out and you start taking things off. Only need pliers to squeeze clamp and loosen hose.
2. Remove air intake. 3 flat head screws to remove air filter box and 1 flat head screw to loosen air intake tube from throttle body. Unclip 2 sensors from air intake tubing and pull everything off in one piece.
3. Unbolt fan from water pump (LEAVE THE BELT ON - THIS HELPS KEEP THE PULLEYS FROM MOVING). Need fan clutch wrench and spanner wrench for this (your local auto parts store should have loaner wrenches - check with them if you don't have these). Spanner wrench teeth go into holes on water pump pulley and fan clutch wrench goes on fan nut. Once the nut is loosened (turn left to loosen) you can spin the fan the rest of the way to come off.
4. Remove fan assembly. Take top radiator hose off from radiator (left side when looking at top of radiator). Unclip two transmission lines from brackets on bottom right corner of fan shroud (need to go under car for this - "bottom right" is looking up, while on the floor, at bottom of radiator). Now remove the 2 10mm bolts at the top corners of the fan assembly/shroud. Unclip fan wire on right side of fan assembly. Now pull the entire shroud and fan up and out of vehicle. Passenger side is a little tricky, it's tight and you need to get it around the left radiator hose mount which sticks out a little. Take your time and it will come out. Don't be afraid to bend the shroud a little but be careful not to hit your radiator.
5. Remove main drive belt (and A/C belt if it's bad). Need a 15mm socket and socket wrench. Turn idler pulley to right and pull loosened belt off pulley. Rest of belt should come off now. Look at your A/C belt to see if it needs to be replaced. Now is the time to do it because it's a pain to do later when everything is put back in. I replaced both of my belts when doing this job.
6. Remove hoses from water pump. There are 4 total. The thermostat is mounted on the front left side of the pump, take that off. Take the next 2 smaller hoses off the far left side of the pump, they have clamps as well. Take the top middle hose off, that should be all 4.
7. Remove old water pump. 6 10mm bolts hold it in place. Remove those bolts and remove pump. Coolant will spill out of pump, nothing you can do.
8. Remove idler pulley and thermostat from old water pump (both need to go on new pump). The idler pulley is on the top left corner of the pump and held on with 3 10mm bolts. Remove the idler pulley. Thermostat is on bottom left corner of pump and held on with 2 10mm bolts. Remove thermostat. Thermostat has black rubber gasket around it. Replace this gasket ($2 at Autozone). Thermostat easily pulls off housing to replace gasket. If you think either the thermostat or idler pulley is going bad now is the time to replace. Mine are fine so I kept them. Mount both of them on the new water pump.
9. Clean mating surfaces. In order to get the best seal possible with your new pump you'll need to clean the area where the new gaskets will go. Clean with a brush and some brake cleaner (or other cleaning solvent). Be careful not to get any solvent in the coolant intakes. The new pump should have come with two gaskets to mount between the pump and motor (where the bolts go). Make sure those are clean. As well, make sure new pump is clean.
10. Mount new water pump and attach hoses. Using the 2 gaskets and 6 bolts, mount the new pump. Make sure it's a tight seal, don't want coolant leaking. Attach the 3 hoses to the pump.
11. Give all pulleys a wipe to clear debris or coolant and put belt(s) back on.
12. Mount fan assembly. Make sure bottom pegs mount into the two brackets (get underneath car and check). Also make sure top middle clip goes into place. Fasten 2 10mm bolts. Clip fan wire back on. Clip both transmission lines back on. Attach top radiator hose. Thread fan onto water pump pulley. You can turn the fan clockwise to thread it most of the way. Tighten with spanner wrench and fan clutch wrench.
13. Put bottom radiator hose back on.
14. Mount air intake system.
15. Put coolant back into radiator. Using a funnel and a clean rag as a screener (debris may have fallen into bucket) pour coolant back into the radiator. Do this slowly and allow the air to bubble out when it needs to. When it starts to bubble out, stop pouring and wait a minute then continue pouring. When the coolant reaches the top of the radiator then put the rest of the coolant in the reservoir. You will have lost some coolant so purchase a gallon of Dex-Cool. DO NOT USE ANY OTHER TYPE OF COOLANT. Dex-Cool is red/orange. It cannot be mixed with green/yellow coolant. Add the new coolant to the reservoir. This would be a good time to do a system flush and add all new coolant if you need it. I flushed my system 20k miles previous to this job so i reused my coolant.
16. Check for leaks. Keep in mind you have spilled some coolant on your engine when removing the pump so there will be coolant on it, but look for any that is leaking from your pump or hoses.
17. Using a little water, rinse off the areas where coolant spilled. Do not get any water on electric components or battery, but just the pump and pulleys.
18. Start the car and listen/watch for any issues. Mine was quiet when I started it up. I let it run for a few minutes and the temperature gauge read normal (210). It did pull some coolant from the reservoir once I drove it around that night so I filled it back up to the proper line. Check for leaks after you drive it around as well as the next day.
19. Brag to all your friends and co-workers about how much money you saved.

Hope this helps.
 
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C-ya

Member
Aug 24, 2012
1,098
Good deal. Yes, I read it all. I had heard about the fan being hard to get loose.

I understand about being busy. Again, I was joshing about the pics/write-up, but if you get around to posting some, it would be appreciated I'm sure.
 

denaliguy

Original poster
Member
Jun 1, 2013
56
I know you were messing. But this forum has been great to me and I'm trying to give back more. I was thinking of doing a tune-up soon. Haven't done a ton of reading on it yet, but I did see how some did not like changing the plugs out on these 5.3's. Were you doing a tune-up when you replaced yours?
 

C-ya

Member
Aug 24, 2012
1,098
Actually, I had a major misfire on one cylinder that caused me to change plugs and wires. Several of my plugs were pretty dirty, the DOD ones, I think.
 

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