Possible Rod Knock

[Blue_Thunder]

I noticed after taking my 86 Camaro to a show yesterday that while I was coasting at low speeds or put my car in neutral a knocking sound would come from underneath the car. The oil pressure is fine. I can only hear the noise when I am coasting at slow speeds with no load or when I put the car in neutral sitting still. The knocking increases in tempo as I increase the rpms. It doesn't do it all the time. The noise is there only after driving the car for about 30 minutes.

[1BADAIR]

make sure the TC isn't loose

[Kwazrollinz28]

sure its not your exhaust leaking. some people think that

[WMCCjames]

Everytime I've heard a rod knock in person the engine had to be under moderate to heavy load. They were quiet under light to no load conditions.

[Blue_Thunder]

hmm, Well the sound is a knock. I dont know if it continues while driving cause my exaust is loud. I don't thinks its my ehaust cause then it should get louder when I throttle up. I have never heard this sound before. It concerns me.

[Lucky SOB]

I don't thinks its my ehaust cause then it should get louder when I throttle up. I have never heard this sound before. It concerns me.

not necessarily. sometimes it gets drowned out by the true exhaust when you get into the mid to high rpm range. i'd have someone just rev it up while its idle'ing and see if you can hear where it's coming from.

[Kwazrollinz28]

not necessarily. sometimes it gets drowned out by the true exhaust when you get into the mid to high rpm range. i'd have someone just rev it up while its idle'ing and see if you can hear where it's coming from.

x2 usually rod knocks get louder like my truck did

[c0ncEpT]

Everytime I've heard a rod knock in person the engine had to be under moderate to heavy load. They were quiet under light to no load conditions.

You should have heard my sisters escort... When she came in and told me something was wrong with it and I went out and started it, it literally scared me because it was knocking so loud at idle.

[WMCCjames]

You should have heard my sisters escort... When she came in and told me something was wrong with it and I went out and started it, it literally scared me because it was knocking so loud at idle.

Well yeah, if you let them go long enough the will rattle all the time.....however, when they just start to knock they only do it under load....at least that's my experience.

[sman]

Not sure what kind of motor were talking about but could possibly be piston slap? Lifter gone bad? Exhaust gasket blown?

[Ace2717]

I had a 91 Silverado with a 350 and it made the exact same noise your describing. It was a loose torque converter.

[1BADAIR]

I had a 91 Silverado with a 350 and it made the exact same noise your describing. It was a loose torque converter.

yeah, I mentioned that. very common. loose or cracked flexplate