Good Day Everybody,
There is some recent history in maintenance and I don’t know if everything I solved is related to the problem I have having now. Bear with me, this is a detailed post but I want to include as much details as possible. To all of you Mechanical Detectives out there, I need help!

Noise:
The Noise is intermittent while driving (May start for 30 seconds and not start again for 15 minutes or may start again in 5. Its random but doesn’t last very long). It does not affect the driving.

The noise can be described as running over the multitude of lines before you get to a stop sign (that is exactly what it sounds like). Increase the speed and the noise gets shorter (in relation to time) as it would running over those lines. The amount of pulses is the same no matter how fast you are going. The decibel of the pulses increase slightly the faster you go. The vibrations get stronger the faster you go. The vibrations are not very strong but become concerning when you get on the highway above 50 mph or so.

I’m thinking something related to the wheel because of the noise and vibrations are directly related to speed of the vehicle. It’s something that is not an emergency but needs to get fixed rather quickly. Also, it could be related to the oil. Did I put too much in? 5 quarts plus a large bottle of stop leak. Read below for the full story.

History:
Recently I had purchased a '99 LS Blazer with 126,000 miles and love it. I knew buying an older vehicle would equal some maintenance and TLC to be done. Test drive successful and I took a guy with me that owns a '00 Jimmy that could point out problems.

I had bought the car in the summer about 3 months ago and didn’t have any problems at all whatsoever for 2 months and then I started to hear a noise in the front left wheel. It went away in 2 weeks and it started to make the same noise in the front right wheel for 2 weeks. Then the noise seemed to be in both wheels ever since.

Noise:
The noise can be described as a rattle similar to when you drink the last bit of soda from your McDonalds cup. The noise also goes away when you are not idling and goes away above 10mph. It does not affect the driving at all.

What did I do?:
Checking the car out, it turns out the noise was not in my wheels but my Cadillac converter. Took it to my uncle who is a mechanic, said he figures it is a piece of the manifold that has broken off and is now in the converter. Not a big deal, we can just straight pipe it and since you don’t have to pass emissions. It shouldn’t matter. The car will be a bit nosier and you’ll open a few more horses and save a little on gas. It’s just going to be annoying as hell until you fix it. Get it fixed within a month or 2.

Ok problem solved. He doesn’t have a stainless welder but he knows a guy who does. His buddy wants $50 for the repair. Good deal to me! I plan on getting it done in a week or so when my work schedule permits it.

Another problem arises:
However, checking out that problem. Visual inspection pointed out that my oil was leaking all over the bottom of the engine. I truly mean EVERYWHERE. I still had 2 quarts left (per the dipstick, thank God). I changed the oil with synthetic 10W30 and put an extended Premium Bosh filter on it and put Lucas stop leak in it. The oil was as thin as water when I changed it and the filter that was there looked like it was starting to crack superficially at the paint finish of the outside of the filter. (I think this is why it was leaking). I hope that the Lucas will fatten up those seals plus 10W30 plus its wintertime and I probably need an oil change anyway. I did put 5 quarts of oil in the engine.

Now the problem and the reason for this post:
Since the day I changed the oil, I now have a noise and vibration underneath my feet when I am driving.

Got a clue?

 

Does the 4x4 work well ? does it still make the sound when engaged into 4lo or hi ?

Have you checked your CV shafts ? How about wheel bearings?

 

It does not have 4x4. Its a 2 door LS. No to checking CV and No to checking wheel bearings. The driving isnt affected at all by the problem (yet). I found this website and am using it as a starting off point to finding out whats wrong. This is a great site, I will stick with it after the problem is fixed.

 

Ok since you dont got 4wd then you would not have CV shafts.

I would jack the front end up and check the wheel bearings. Im not sure if you have a 2 pc or a full driveshaft. if you have a 2 pc driveshaft you should have a carrier bearing. Inspect that.

Edit: Try taking a video of the sound it can help us pinpoint the issue better.

 

Thank you for helping me out.
You have to make it explicit and dummy proof when it comes to mechanical work, my background is in medicine/military.

I googled and printed what those parts you mentioned look like so I know what I am looking for.

Inspect those parts for rust, dings, dents, parts/pieces missing, etc...
Right?

Also, I will get that video of the sound and will also post the inspection.

 

To check the wheel bearings, jack the truck up until the front tires are off the ground, and wiggle the tires, and 9 and 3, and then at 12 and 6... see if there is any play... then manually spin the wheels by hand to hear if you can replicate the clicking that you are hearing

 

Thank you, I will try that. Any tips for finding the carrier bearing and checking it (if a 2 piece driveshaft)? Drive shaft inspection seems straight forward (cracks), but how would you check movement? Turning on the car and being underneath seems like a saftey issue.

 

Up and down motion and side by side motion. IT shouldn't have much play.

 

Thanks,
I don't see a point posting a video on the inspection then. It seems very straightforward. I will post the video of the sound though. I will do the inspection tomorrow and post the video sometime tomorrow afternoon/evening. Thank you again for the help. Both of you.

 

there was no mention of you posting a video of the inspection. just the sound.