Knocking when cold. I think.

[Chatchie]

This morning I started my truck to go to work and it was knocking/ticking pretty loud. I shut it off and checked the oil, level was perfect and oil was still clear.

I took it for a ride and it slowly started to go away. Ran silent and perfect after about 3 minutes.

After work I start my truck and it does it again for about 45 seconds then slowly fades away.

I know some trucks will tick for a few until oil gets to the top of the engine but in my case case it doesnt just "stop" like in those cases.

It almost sounds like my exhaust manifold has a leak that seals as it warms. Is that a common issue with these engines?

I always stay on top of maintenance and my truck, up until today, ran perfect. Very smooth and very quiet motor. Any ideas?

Its a 97 with a 350 vortech.

 

[TORONTO 95 GT]

I had a 96 V6 that did the exact same thing. I woke up one morning and I could hear every valve in it shut it off and checked the oil and all was clear and perfect. After it warmed up it was quiet like always. When it cooled down I started it again and it was noisey so I drove straight to the dealership as the truck was still under warranty. When I got there it was queit but I told them when it would happen and left it there. Later that day I get a call and they tell me that they tried it and it wasn't making any noise so I told them I would leave it with them until the next day and they could check it in the morning.

I got a call the next day and I think the service advisor was scared at least he sounded like he was when he told me he had never heard a motor make that kind of noise. Well after further investigation it was found that there was an antifreeze leak from the intake into the engine and even though it was not showing in the oil yet it was enough that it was washing out the lifters.

I hope yours is not so serious as I did get a new motor out of the deal but it was warranty.

 

[retorq]

Have you checked the exhaust manifold bolts?? They have been known to break ...

 

[Chatchie]

So its definitely a knock. Kinda weird that the motor is silent once it warms up a bit. Ill post once I figure out what im gonna do. Im thinking a junkyard motor will get me a few more years.

 

[ERIC95TAHOE]

So its definitely a knock. Kinda weird that the motor is silent once it warms up a bit. Ill post once I figure out what im gonna do. Im thinking a junkyard motor will get me a few more years.

mine does the same thing i chalk it up as piston slap and ignore it
mine seems to be worse in the winter when its colder out, warm weather it doesn't seem to do it as much and not as long.

 

[retorq]

If it was a bearing knock it would most likely not go away when warm. If anything it would get worse cause the oil is thinner ...

 

[Chatchie]

Yeah I don't get it... its not like its a small tick. Its a loud knock. Then 2 minutes later it runs brand new silent.

 

[arb905]

I ran into a similar problem when I put my new motor in. Check your belt tensioner. My belt stretched so much the tensioner was bumping off the limiter stops. If that is it then its time for a new belt and tensioner. Watch the tensioner as you rev the motor. You'll see it hitting the stop.