6 cyl. ticking noise from engine

[ace57]

Hi folks,

In the last few months or so I am hearing a "ticking" noise coming from the engine. Seems to have gotten worse.

I know asking a noise question on a forum is pretty vague, but could this be the dreaded "exhaust manifold" crack that I hear many people have had?

The truck is a 2000 6 cylinder with about 146k on it.

If I do find out it is the exhaust mani crack, what are people doing about it? Replacing a stock exh mani versus headers for a 6 cylinder? Buying aftermarket or toyota OEM?

If I do not fix the "leak", is it possible to do futher engine damage, such as warping the heads or such?

Finally, I have had a persistant PO420 code, so could this be related to the possible exh mani crack, or is it more likely that the cat is junk as well?

I know its a lot of speculation here to ask all this, but any ideas or info. would be most appreciated.

thanks
ace57

[m5allen]

It is probably an exhaust manifold leak. Just try to listen and pinpoint the sound. Also, get an adjustable mirror and look at your manifold – and look for possibly a missing manifold bolt. If it bothers you, replace the manifold and gasket. Otherwise, keep driving it.

[BamZipPow]

It is most likely the heat shield...check it near the crossover pipe in the back of the engine area...

[kashufran]

I have similar "ticking" with 3.4 V6 on 1998 T-100, 4x4 with Auto transmission. 140K miles. Sound coming from drivers side, rear, and seems underneath. Ticking occurs when in Neutral and quits when accelerator is depressed. Also occurs in Drive when truck is stopped with foot on break. When in drive and foot on break, noise also stops when acclerator is depressed. has only gotten slightly louder after first hearing it 6 months ago. occurs with hot or cold engine.

Any thoughts on this would be helpful. I will be getting a stethoscope and pin point where its coming from.

thanks

Kevin

Originally Posted by ace57

Hi folks,

In the last few months or so I am hearing a "ticking" noise coming from the engine. Seems to have gotten worse.

I know asking a noise question on a forum is pretty vague, but could this be the dreaded "exhaust manifold" crack that I hear many people have had?

The truck is a 2000 6 cylinder with about 146k on it.

If I do find out it is the exhaust mani crack, what are people doing about it? Replacing a stock exh mani versus headers for a 6 cylinder? Buying aftermarket or toyota OEM?

If I do not fix the "leak", is it possible to do futher engine damage, such as warping the heads or such?

Finally, I have had a persistant PO420 code, so could this be related to the possible exh mani crack, or is it more likely that the cat is junk as well?

I know its a lot of speculation here to ask all this, but any ideas or info. would be most appreciated.

thanks
ace57

[5 Speed]

The P0420 might be a loose connection in the exhaust inbetween the cats. Here is a little information. I have been throwing this code for 4 years and I know it isn't the cat. because I have had two smogs tests and the smog tests are perfect. I have a scan gauge and just reset it on the move and then 4-6 months later it throws the code and I just reset it. In fact it threw the code twice on the end of a long downhill one year apart! How interesting is that! Now it might be the O2 sensor after the cat is getting old because I have 134K and it is the original sensor and as long as I can reset the code I am not going to change the sensor. It does not change the closed loupe, it is just a sensor. I have the california V-6 and the first sensor pre cat is a more expensive air-fuel ratio sensor and this is needed to run closed loupe so when it went out I replaced it.

[Sandinmytires]

Originally Posted by kashufran

I have similar "ticking" with 3.4 V6 on 1998 T-100, 4x4 with Auto transmission. 140K miles. Sound coming from drivers side, rear, and seems underneath. Ticking occurs when in Neutral and quits when accelerator is depressed. Also occurs in Drive when truck is stopped with foot on break. When in drive and foot on break, noise also stops when acclerator is depressed. has only gotten slightly louder after first hearing it 6 months ago. occurs with hot or cold engine.

Any thoughts on this would be helpful. I will be getting a stethoscope and pin point where its coming from.

thanks

Kevin

Might be the insides of your catalytic converter have deteriorated. Under low exhaust pressure it rattles or ticks. Higher pressure prevents the rattle or perhaps masks it. Give it a shake when its cold.