Hi

Recently bought a 2001 Chevrolet suburban with 364 6.0l engine. The car has around 150 000 miles to it. It has a ticking noise at startup. This goes away when warm at idle. But it appears around 1500-2500 rpm or under some load when driving. There are no error message or bad symptoms on the engine. It runs great and oil pressure is excelent. The sound is annoying me, I would like to get it fixed, but dose anyone have a clue what this can be? I noticed a faint of exhaust from the engine room, so I was thinking about a exhaustleak, but my father inlaw suspected a "short" pushrod because of the "mechanic sound". So again, any clue where to start? I got the car real cheap because of this noise...

Sorry about my english. Im Norwegian.

 

Welcome to the forum. Your English is fine. I would check for exhaust leak first, primarily around the manifolds. It can also make a mechanical clicky sound that goes away when the engine warms up.

 

Thank you. I noticed exhaust comming out around the manifold when I started the engine. Can exhaust leak tick under load?

 

Possibly. Another thing you can use to try to isolate the source of the noise is a mechanic's stethoscope. Also you could use a piece of rubber tubing. Place one end at your ear and the other end around the exhaust manifold to see if that can further isolate the source.

 

When the car is parked and I rev the engine I can hear this clattering/ticking sound at some rpm. I used a long wrench and pointed it on different spots on the engine. I revved the engine and listened on the heads, manifold, bottom of the engine and middle of the engine. The ticking/clattering diddent come from any of those spots. If the ticking came from the engine, wouldn't it have echoed trough the metal parts?

The noise is worst when I drive. It goes away immediately when I let of the gass pedal despite high RPM.

 

An exhaust leak would not create a noise that would transmit mechanically throughout the engine. That's why I suggested using a hose to see if you could isolate it as an exhaust leak.

 

I have now isolated the source to around spark plug nr 1. The sound goes away if I pull that sparkplug hose. So I guess its not a exhaust leak.. Maybe a stuck lifter, but wouldn't that have caused an error message?

 

I really dosent hope this is rod knock....

 

Pull the plug and look to see if it's in firing normally. If it has then I suspect you have some mechanical problems but you should have been able to detect those with a mechanic's stethoscope. Also check to make sure that the spark plug itself is not broken.

 

I pulled the plug. It looked normal. I bought a stethoscope aswell. The tick/knock dosent appear if the plug cap is disconnected. I guese a lifter tick wouldt be present regarding if the sparkplug is enabled or disabled.... The knock/tick aint that loud but i can hear it inside the car.