Grinding/Rumble Sound When Changing to Reverse on Cold Start, Gets Worse With AC On

Maintenance/Repairs
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1

I have a 2005 Camry with about 199k miles. 2AZ-FE engine (2.4 L) and U250E Automatic Transmission.

Related History:
Upper Dog Bone Mount - Replaced at 160k
Transmission Filter Drain and Refill - 186k
Alternator - Replaced at 193k
Serpentine Belt - Replaced at 196K
Serpentine Belt Tensioner - Replaced at 194k
Motor Mount on Engine - When I replaced the tensioner, had to jack up engine looked OK
Front Motor Mount - When I replaced the tensioner, had to jack up engine looked OK
Transmission Motor Mount - Last time I did oil change and rotated tires (195k), I don’t recall it looking bad.

You may have to turn up the volume to hear the issue I’m describing.

20 Seconds - Rumble when going into reverse from park
35 Seconds - Going into Neutral
38 Seconds - Going into Drive, also a slight rumble
43 seconds - going back into Neutral, RPM goes up you can hear it
44 Seconds - Going back into Reverse, rumble and grinding sound
1 Minute - Turning on AC - Loud rumble, seems to be coming from front right of the car, lasts for a few seconds and goes away

When going into reverse from park and not moving, I’ve noticed a rattle sound. Has been this way for a few years, and I’ve just ignored it, as I couldn’t identify the source. However, it seems that the issue is getting worse.

On a cold start (and only a cold start), with my foot on the brake, and going from Park to Reverse I notice the rattle sound I typically do. While in reverse and turning on the AC I hear a loud rumble sound. This only happens on a cold start. As you can see in the video, the rumble goes away after the AC has been on for a few seconds. I get nice cold air. I do not hear the rumble when going into reverse after the car has been driven for a bit. It seems to only be an issue at cold starts. If I’ve been driving for a bit, and turn on the AC, no loud rumble.

I’m not sure if I should just ignore this issue or try and fix what’s causing the rumble. Any suggestions on what it could be, or how to further diagnose, would be appreciated.

I recently checked the power steering and coolant reservoirs, and they are nice and full.

Maybe the rumble when going into reverse, and the rumble with the AC on for a few seconds are unrelated problems, I don’t know.

Thanks!

2

A rumble sound when first going into reverse, I’d be thinking the motor is twisting and opening up an exhaust system leak. Does it get louder if you hold your foot on the brake pedal and give it a little gas? That will twist the engine a little more, may provide a clue.

If you can do it safely, inspect the front part of the exhaust system. From exhaust manifold to cat, esp the flexible tube section. Do you see any black carbon marks indicating a possible exhaust leak?

3

Hey thanks for the reply.

I forgot to mention that I replaced everything highlighted in yellow, less than 5k miles ago.

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The section of pipe that includes the catalytic converter and flex pipe,
The middle section of pipe
and muffler.

One thing interesting I noted about this car, is that there’s a circular piece of metal that goes onto the exhaust pipe prior to the flex section which gets mounted to the car. Meaning whenever it vibrates it would in theory vibrate the whole car, highlighted in green. I also noticed that this car does not have bolt springs. I did not replace the exhaust manifold. I do hear a winding sound when accelerating, might be an exhaust leak.

I guess the only way to know for sure is a smoke machine? I didn’t see any black carbon stuff on the outside of the exhaust. The exhaust manifold is VERY very rusty.

Im wondering if spring bolts would help with movement, before the green bracket, connecting the pipe to the exhaust manifold?

4

Are you the poster who pressurizes the exhaust pipe from the rear (using an air compressor presumably) and then checks for any air leaks? I’ve never used that method myself, but according to a u-tube vdo I watched it works pretty good.

Toyota Corolla exhaust manifolds in my Corolla’s era (early 90’s) are know to crack sometimes, not sure about your era’s Camry. If you think there might be an exhaust leak, esp at the front part of the exhaust system, don’t ignore b/c it will adversely affect the air/fuel mixture & cause no end to the engine performance problems.