Hi all — while driving my 92 Camaro RS V6 3.1L recently I started hearing an occasional “clunk” or “thud” sound from under hood (possibly felt through the acceleration pedal, too).

It’s difficult to tell but I think it is worse during acceleration and braking, sometimes occurring when just driving steady on side streets.

I got some video of the engine with the hood popped — no clunking sound but some motion of the engine itself. Is this an unhealthy amount of movement for the engine? Is it time to redo the mounts?

Here’s the 10 second clip of the engine:

Thanks!

 

Lots of things including bad engine or transmission mounts can cause clunking sounds on a 28 year old vehicle. A link to a video on diagnosing bad mounts is at the end of this reply. Loose or failing suspension part or accessory bracket can cause noises also. I had the power steering bracket crack only find it is no longer made by GM. There was noise from the engine compartment before it failed.. A thorough inspection of the front end, brakes, engine mounts and engine accessories may help you find the problem.

Schrodingers Box

An overlooked technique for diagnosing bad engine mounts. Just doing the "rocking test" does not always show the problem!!

 

Thanks for this! Upon further inspection, I think I can rule out the mounts.... I suspect something suspension related now so I need to dive into the rods, arms, and bushings and see what is loose or dead.

 

Upon even further inspection, it looks like my tie rod bushings have had some accelerated grease loss in recent times -- the ones on the passenger side were nearly dry and the tie rod was very loose. I gave the vehicle a chassis lube (as a quick fix before I dive into doing a rebuild/replace in the future) and it has fixed the issue! Seems like that tie rod was bouncing around a lot with the suspension moving.

I was able to reach 7 out of the 9 zerk fittings on the bushings for lubing... I need to get a 90 degree adapter or something similar to get to the ones in the top-most positions where the fittings would face toward the rear of the car.

Anyway, I'll call this resolved (and a note to future folks who hear clunking in the future and automatically thing "engine mount" first).

 

The clunk will be back sooner than later . If the tie rod is "very loose" greasing will shut it up for the very short term , but the play in the ball & socket will pound that grease out in no time .

If it gets bad enough and separates , well , best to not go there and replace it now rather than tempt both Darwin and the Gods of fate at the same time ......

 

Fair point! I haven't been driving many miles lately, to be honest, due to the pandemic so maybe my band-aid will last a little longer than a daily-driving situation. Regardless, I've added the parts required to rebuild to my shopping cart so that it will remind me to pull the trigger in the next month!

 

Quick update — after driving around the block about 3 miles for a checkup, I started hearing the clunk again. Snapped a photo of that passenger side outer tie rod bushing oozing. Yeah, maybe I’ll just go ahead and rebuild...