Thread: pontiac grand prix 3.8L ticking knocking noise when cold

I have a 2005 pontiac grand prix with 144,000 miles on it. After the first freeze this year, it started making a loud tapping/ticking/slapping noise from the bottom of the engine compartment just like in this video https://www.youtube.com/watch?v=Yfw08eFUWZk

The video is of someone else's 2006 Grand Prix but it is the exact same noise and situation. It only happens when the vehicle is cold and the sound gradually fades as the vehicle warms up until it is completely gone.

The is no check engine light on or pending codes. The vehicle drives fine.

I got the oil changed shortly after the noise started but no change. I had the transmission rebuilt/replaced 3 months ago.

I do know, with the 3100, 3400, and the vortex engines in the trail blazers, they all do this problem, ticks when cold and once it warms up it goes away, never with the 3800 though. Its the lifters making this noise, but with the 3800 ive heard it could be many issues.

Hey man, just a thought... Get the torque convertor bolts checked. Seeing as you had the trans redone... There's 3 of them, and you can visually inspect them via removing the inspection plate.
Just a "to make sure" thing.

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Originally Posted by Scottydoggs

i bet your way over due for a oil change. thats your lifters not pumping up. they are bleeding off over night, so its the rockers clicking. GM says this is fine as long as it stops in like a minute or two.

mine will start to do this when im due for a oil change, like clock work really. change the oil and filter, it stops. i also have like 230,000 miles on my old beater.

I did quite a bit of research before posting on all these forums. Lifters was the first thing I could come up with based on others issues. I got the oil and filter changed right away but nothing changed. I also heard people say to put some lucas or seafoam in there. I did that yesterday and we will see what happens.

The noise, however, does seem to be coming from deeper in the engine by that I mean towards the bottom. I am no expert but aren't the lifters towards the top/on the top of the engine?

Originally Posted by jimzssei

Hey man, just a thought... Get the torque convertor bolts checked. Seeing as you had the trans redone... There's 3 of them, and you can visually inspect them via removing the inspection plate.
Just a "to make sure" thing.

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I am going to take it back to the tranny shop this week to check the bolts. I also heard if they put the inspection cover back on wrong that could slap or the flex plate can rub up against the inside of the cover making a noise. I just pray to God they didn't mis-align the engine and transmission when the put it back in and my flex plate has cracked. My foot would be going up someone's butt. It's only been 3 months and maybe 1500 miles. Surely they would be on them. I blew my extended warranty replacing the transmission. The transmission is supposed to have a 3 year/75,000 warranty. I pray I don't its not the flex plate and I have to pay for it because I don't know where that money will come from

The you tube video link you posted sounds bad! I know that's not your car. My thoughts on the flex bolts are via experience. The lifters are located in about the center of the engine. I've never heard a lifter that loud.
I wise investment is a mechanics stethoscope with a piece of brake line on the end.

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My 5300 in my 2000 suburban has done this since new. I just let it warm up idling before I put a load on it. Couple of minutes.


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LSx , especially in the trucks, are known for their weird engine ticks and knocks lol

Sent from Browns country

Originally Posted by Scottydoggs

i hope you didnt put the seafoam in the oil. thats a no no around here, causes more issue then good.

a member here had a good full time tick that seafoam used in the vac lines fixed up for him. had a vid for proof, the ticking just went away.

I did put some in the oil as the instructions say you can do and as I have seen in multiple videos. What kind of trouble are we talking about? Now I wonder if I should get the oil changed again

Ya, seafoam is basically kerosene (with their own chemicals mixed in) , so you can imagine that the viscosity of the oil is very thin.
And the crazy other issues that can arise from cleaning the inside of the engine.
I would definitely get an oil change.

Sent from Browns country

Hello everyone I just joined the community and it is nice. I also joined to find out what the ticking noise is in my 3800. It does not do it when its cold, only when it warms up and then it only does it at idle. If I give it gas it goes away. I am almost positive it is the lifters but I just wanted to be sure.