Knocking/Ticking Under Engine Bay

[OneEightSeven]

Hey guys,

I realize this is probably going to be impossible to diagnose without hearing first hand, but I've noticed a tick/knock coming from under the car. Middle of the car by the sound of it, can be heard from behind front wheels on either side. I do not hear it from the top of the engine bay when I pop the hood so I'm thinking it's not lifter tick. It comes on when I first start the car for about 10-30 seconds.

Some times if the car is not warm yet (and some times on a warm start) I can rev to say 1500RPM and come off the gas and hear it when it drops off. The sound will last from about 1000RPM to idle 500RPM, but it's not heard at all at the 1500RPM (or higher). I had an engine swap about 10k miles ago to an engine with about 45k miles so it puts it at about 55k miles on the engine. I'm thinking maybe something is vibrating (headers or something?) Oil pressure is fine. No SES.

Does the symptom of the noise happening coming off the gas mean anything to anyone? I'm probably going to get my mechanic to listen to it tomorrow if he has a chance. I got to help my friend take her car into the shop anyway, because her little brother rear ended an 18 wheeler and lost her bumper (it got stuck to the 18 wheeler and the truck driver didn't even notice... LOL!)

Thanks in advance! :rock:

[conbirdable]

Re: Knocking/Ticking Under Engine Bay

Hey guys,

I realize this is probably going to be impossible to diagnose without hearing first hand, but I've noticed a tick/knock coming from under the car. Middle of the car by the sound of it, can be heard from behind front wheels on either side. I do not hear it from the top of the engine bay when I pop the hood so I'm thinking it's not lifter tick. It comes on when I first start the car for about 10-30 seconds.

Some times if the car is not warm yet (and some times on a warm start) I can rev to say 1500RPM and come off the gas and hear it when it drops off. The sound will last from about 1000RPM to idle 500RPM, but it's not heard at all at the 1500RPM (or higher). I had an engine swap about 10k miles ago to an engine with about 45k miles so it puts it at about 55k miles on the engine. I'm thinking maybe something is vibrating (headers or something?) Oil pressure is fine. No SES.

Does the symptom of the noise happening coming off the gas mean anything to anyone? I'm probably going to get my mechanic to listen to it tomorrow if he has a chance. I got to help my friend take her car into the shop anyway, because her little brother rear ended an 18 wheeler and lost her bumper (it got stuck to the 18 wheeler and the truck driver didn't even notice... LOL!)

Thanks in advance! :rock:

I would look at your header flange gaskets first.

[pace2006]

Re: Knocking/Ticking Under Engine Bay

I would look at your header flange gaskets first.

X2 I've got a slight leak from the header gasket on the right side. But I only hear a slight tick when it's idling. Matches the idle, but can't hear it when I give it gas.

[OneEightSeven]

Re: Knocking/Ticking Under Engine Bay

X2 I've got a slight leak from the header gasket on the right side. But I only hear a slight tick when it's idling. Matches the idle, but can't hear it when I give it gas.

Yea it's really quiet. I can't hear it in the car at all. I can't even really hear it from the front of the car. The only time I can hear it is if im parked between cars and open my door (can hear an echo of the tick), or if i bend down and listen behind the front wheels. I also had my cat replaced with a cheap aftermarket one about a year ago. Wonder if that's shot/clogged maybe. Due to work and all I haven't been able to lift the car myself and listen. Gonna see if I can run out the office for a bit and help my friend take her car to the shop and have him lift my car and listen real quick.