Top end/valve "fluttering" sound under load

[mendyourline]

I have put about 7500 miles on my rig since I purchased it a few months ago and have been loving it. Ever since my purchase however, I have noticed a very light fluttering chatter noise that corresponds with engine speed under high load that was originally only noticeable with the windows down while I was driving next to a wall or something. Recently I have noticed it getting louder to the point in which I can hear it coming from the passenger side of my truck while driving. For example: Not noticeable accelerating through first, only barely noticeable in second, but when I shift into third and fourth or step on it to get on the highway, boom. Fluttering noise. I cannot recreate the noise at idle or revving the engine up to attempt to diagnose something myself. My first thought is valves as I don't believe they have been checked or adjusted in the life of the vehicle. My 2000 has the 3rz-fe engine and has 142xxx on the clock. Thoughts?

 

[cashman]

Check your exhaust manifold for leaks / cracks.

 

[JayRolla]

I have put about 7500 miles on my rig since I purchased it a few months ago and have been loving it. Ever since my purchase however, I have noticed a very light fluttering chatter noise that corresponds with engine speed under high load that was originally only noticeable with the windows down while I was driving next to a wall or something. Recently I have noticed it getting louder to the point in which I can hear it coming from the passenger side of my truck while driving. For example: Not noticeable accelerating through first, only barely noticeable in second, but when I shift into third and fourth or step on it to get on the highway, boom. Fluttering noise. I cannot recreate the noise at idle or revving the engine up to attempt to diagnose something myself. My first thought is valves as I don't believe they have been checked or adjusted in the life of the vehicle. My 2000 has the 3rz-fe engine and has 142xxx on the clock. Thoughts?

I can almost guarantee that its a crack on the exhaust manifolds heat shields. Pop hood, look at the exhaust manifolds near the firewall, rev motor from under hood and look at the shields. They will crack and vibrate like crazy and will sound just like chattering valves.

 

[mendyourline]

I can almost guarantee that its a crack on the exhaust manifolds heat shields. Pop hood, look at the exhaust manifolds near the firewall, rev motor from under hood and look at the shields. They will crack and vibrate like crazy and will sound just like chattering valves.

Great point, I didn't even consider that as a possibility. Anything specific I should be looking for? I know for a fact I cannot recreate the noise unless the engine is under load. It actually runs pretty quietly at idle and while revved in neutral. Is the EM still a possible culprit?

 

[mendyourline]

I can almost guarantee that its a crack on the exhaust manifolds heat shields. Pop hood, look at the exhaust manifolds near the firewall, rev motor from under hood and look at the shields. They will crack and vibrate like crazy and will sound just like chattering valves.

What is the best way to check for leaks if they are not obviously visible?

 

[jgue467]

Start with EZ stuff

yeah start with low cost, EZ stuff like exhaust leaks, could be anywhere besides EM. There are several connection points in front/behind each converter then there are additional connections after the EM. If you can't tell by listening then take it to a muffler shop, they're Experts and can tell in an instant. Luck. :smokin:

 

[mendyourline]

yeah start with low cost, EZ stuff like exhaust leaks, could be anywhere besides EM. There are several connection points in front/behind each converter then there are additional connections after the EM. If you can't tell by listening then take it to a muffler shop, they're Experts and can tell in an instant. Luck. :smokin:

Is it still a possibility if the sound is only visible under load? Going to go through it tonight.

 

[jgue467]

I'd say Yes because the heavier load maybe what causes a flex in some exhaust/engine component which then allows the leak, it may 'seal' up completely or nearly to the point you cannot hear it under lighter loads. If its not an exhaust leak then you have to move onto other possibilities. It may help if you can post a vid w/some audio of what you're hearing. :^)

 

[Jacob_116]

I have put about 7500 miles on my rig since I purchased it a few months ago and have been loving it. Ever since my purchase however, I have noticed a very light fluttering chatter noise that corresponds with engine speed under high load that was originally only noticeable with the windows down while I was driving next to a wall or something. Recently I have noticed it getting louder to the point in which I can hear it coming from the passenger side of my truck while driving. For example: Not noticeable accelerating through first, only barely noticeable in second, but when I shift into third and fourth or step on it to get on the highway, boom. Fluttering noise. I cannot recreate the noise at idle or revving the engine up to attempt to diagnose something myself. My first thought is valves as I don't believe they have been checked or adjusted in the life of the vehicle. My 2000 has the 3rz-fe engine and has 142xxx on the clock. Thoughts?

Sorry to dig up an old thread but did you ever find a solution?

 

[brillo_76]

If its not cracks in the heads or exhaust system.. If over 250K miles.. Its due for a valve clearance check.