knocking by timing belt

[ivan300]

When the car is cold i get this really loud tapping sound by the timing belt. its a rhythmic tap that does not get louder as the rpm increases. The sound gets really quiet when the car warms up. I can still hear it a little when i go into an ally.
My timing belt was changed a few months ago. The watter pump was supposed have been changed by the mechanic but i have no way of knowing. I should have done it myself but i didn't have time.


Ive had this before i turbo'd my car
It has 140k miles on the engine. Im not sure if it was rebuilt
compression is 200 on all 4 cyl's
The car is running great

 

[Locke]

It is a 'tick', or a 'knock'?

If it is a loud tick, it may just be a bad adjuster.

 

[4UH8ERS]

It could just be lifter tick. Is the knocking really fast or slow? and does the ticking/knocking go faster when rpm's increase?

 

[ivan300]

it becomes faster when i raise the rpm. i cant really say weather its a tick or knock . ill pull the valve cover tomorrow and inspect the lifters.

 

[Defiant]

Harmonic balancer.

 

[SurrealDSM]

i had this sound coming from my timing belt cover it sounded kinda like it was rattling and as i rev'd it it went away after a certain RPM but went away when the car warmed up and also it was only happening when the car was ice cold so my .02 cents it may be the tensioner becasu that was my problem when i had this sound occur in my 2gnt

 

[xceler8]

wouldn't a bad lifter causer low vacuum too? is you boost/vacuum low at idle?

 

[xceler8]

correct me if i'm wrong defiant, the 4g63 has a harmonic balancer, but the 420ai know doesn't. That would probably sound lower like around the pulleys rather than the cylinder head.

 

[ivan300]

my vacuum is around 15 at idle

 

[xceler8]

stock internals? You said your didn't know if it has been rebuilt. Your compression looks good on your cylinders, it could be something in your head. Pull your valve cover and see if something looks out of place.

 

[RWKustoms]

i had this sound coming from my timing belt cover it sounded kinda like it was rattling and as i rev'd it it went away after a certain RPM but went away when the car warmed up and also it was only happening when the car was ice cold so my .02 cents it may be the tensioner becasu that was my problem when i had this sound occur in my 2gnt

Bingo!!

When the car is cold i get this really loud tapping sound by the timing belt. its a rhythmic tap that does not get louder as the rpm increases. The sound gets really quiet when the car warms up. I can still hear it a little when i go into an ally.
My timing belt was changed a few months ago. The watter pump was supposed have been changed by the mechanic but i have no way of knowing. I should have done it myself but i didn't have time.

Tension your belts. Both Alt and PS, but most likely it's the Alt. belt. I promise you this is your problem. I had the same exact problem, you described it down to a T.

 

[xceler8]

When my alt belt was loose, it didn't make a knock noise, or anything like that, it made a squeal. I tightened it and it went away.

I don't see how a loose tensioner can make a knock.

 

[RWKustoms]

A squeal is also a possibility, but that tapping sound that got louder upon acceleration is something that I experienced personally. I used to think that my timing tensioner/idler pulleys were making the noise because the sound was right by the timing cover but one day I sprayed belt dressing on the alt. belt while the car was running and it went away temporarily for about 5 mins and then came back. Tensioned the belt and it went away for good, belts dont only make a squealing noise.

It could always be another problem but reading his description was like deja vu all over again especially since the problem occured after a TB/WP job also.

 

[SurrealDSM]

it has to be the tensioner i never thought it was the belt but his description is exactly what i went through as well

 

[freshlane]

wow.... solved my problem. Sometimes I get the squeal and other times I get the 'knocking' sound.

 

[cyrez187]

so i hear this ticking sound and while i rev and accelerate it goes away, so i thought it was one of my lifters replaced them all and it is still making this noise help please

 

[SurrealDSM]

so i hear this ticking sound and while i rev and accelerate it goes away, so i thought it was one of my lifters replaced them all and it is still making this noise help please

wheres your ticking sound coming from?

 

[Locke]

Are you building good oil pressure?

Do a compression test to see if you have a damaged valve.

 

[cyrez187]

well it sounds like its comin from the valve train, near the inside of the valve cover. my oil pressure is perfect. ill do a compression test today..........

 

[96Eclipsed]

i had this sound coming from my timing belt cover it sounded kinda like it was rattling and as i rev'd it it went away after a certain RPM but went away when the car warmed up and also it was only happening when the car was ice cold so my .02 cents it may be the tensioner becasu that was my problem when i had this sound occur in my 2gnt

I had that happen recently...At idle there was a knocking or knuckling like sound but when I got to 3000+ rpms it went away. Took it to the shop who said that the timing belt tensioner had come off....

 

[SurrealDSM]

when you have that "knocking" sound it sounds like its coming from the valves rockers or lifters even the cam gears but ironically it ends up being the tensioner cyrez check your tensioner it never hurts to check before you go and pay someone to check it for you

 

[cyrez187]

ok ill do that, i took a needle sethascope, and it sounds like it is comin from inside the block

so i did a compression test today and got 160,205,205,100

 

[Locke]

Pull the head off and take a gander.

 

[cyrez187]

really didnt want to, hoping it would be easy but i guess i have no choice

 

[xceler8]

ok ill do that, i took a needle sethascope, and it sounds like it is comin from inside the block

so i did a compression test today and got 160,205,205,100

ouch! I did a writeup about a week ago in the 420a section about doing compression tests.

Pull the head and inspect your cylinders/valvetrain