2003 Chevy Blazer knocking

Believe it or not there is a bullitin out and your problem is probably the hood hinges. There are special cone shape washers to install on the hinge bolts. I also have a 2003 blazer and it fixed the problem. Very simple fix. Read this post.

I thought I found that the sway bar bushings were causing my front end passenger clunk and popping but guess what, they weren't.

Before I drop the bomb and show what I learned through scouring the internet, I have replaced the following:

Lower Ball Joints
Passenger Upper Ball Joint
Sway Bar End Links (Had to be replaced Anyways)
Sway Bar Bushings
Front and Rear Shocks

Total bill: US$600

After all of that, it wasn't even the problem. There is a service bulletin that talk about this in this upcoming video.

Remove this 7mm screw holding the small outer cowl inserts over the hinges. Close the hood.

Remove the covers carefully and don't break the clips.

The hingles will be attached and they are a 13mm nut and bolt.

97PUO-BDM0o

That's right, a $2 dollar part fixes this problem that has ****ed so many Blazer owners off.

This is the service bulletin that came out in 2001 I believe. Covers all S10 and Blazers.
Hood hinge clunk fix
TSB 01-08-63-001A
GM part # 12383460
This bulletin is being revised to add model years. Please discard Corporate
Bulletin Number 01-08-63-001A (Section 08 -- Body and Accessories).
Condition:
Some customers may comment on a rattle coming from either or both front
corners of the instrument panel near the hood hinge areas. This noise may
often be mistaken for a loose shock absorber. The rattle may be heard when
driving over rough roads and is most noticeable when the road surface
creates a side-to-side vehicle motion.

Cause:
Excessive clearance at the hood hinge attaching bolt may cause this
condition. The excessive clearance allows the hood hinge to make metal
contact with the hood hinge bracket, which produces a rattling noise.

Correction:
Important: For additional information, see the Body Front End subsection of
the Body and Accessories Section of the appropriate Service Manual.

1. Remove the hood hinge attaching bolt (1).
2. Install a spring washer (2) on the bolt as shown in above
illustration.
3. Install the bolt.
Tighten
Tighten the bolt to 25 NÂ m (18 lb ft).

Parts Information
Part Number: 12383460

Description: Washer - Hood Hinge

Also, if it is more of a crunching, krinking noise check your door hinge pins for play. To do this open door and lift door and check for play up and down. If you have any play you will get knocking noise. Replace door pins and bushings top and bottom. Parts cost about $10.