Motor rattle scaring me.
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 960
Likes: 1
From: Trussville AL
Motor rattle scaring me.
I know its next to impossible to diagnose problems through forums but I was going to head out on a vacation drive but may be too scared of a motor issue.
01 vert A4 no mods other than Vararam and Corsa axle back 47k miles.
I let the car idle to temperature and no rattle, knock, lifter tick or whatever. A gradual increase in rpm still in park and I get a rattle from the motor from 1100 to 1700 rpm. Once I go above 1700 it goes away. Back at idle it goes away but in that rpm range it sounds bad enough to park it. Any ideas? Lifter possibly?
Thanks in advance.
01 vert A4 no mods other than Vararam and Corsa axle back 47k miles.
I let the car idle to temperature and no rattle, knock, lifter tick or whatever. A gradual increase in rpm still in park and I get a rattle from the motor from 1100 to 1700 rpm. Once I go above 1700 it goes away. Back at idle it goes away but in that rpm range it sounds bad enough to park it. Any ideas? Lifter possibly?
Thanks in advance.
Burning Brakes
Joined: Dec 2003
Posts: 1,243
Likes: 5
From: Loveland CO
Your sure its from the motor not a heat shield or something? I would think a Lifter/Rocker/Valve/Ect would occur at all rpms and even more so at higher RPM's. if you cant tell it might be best to have a Mechanic diag it... worth the 40-50$ to know 100%.
Does it rattle in Neutral, In gear or both... and i assume you dont have any codes and you do read oil pressure on the dash.. does it sound like its from the Front, back, left side, right side of the motor or the center? if it changes with RPM then you can know it is most likly rotational... Alternator, PS pump, Idler, Tensioner would be easier to hear from the front.
Does it rattle in Neutral, In gear or both... and i assume you dont have any codes and you do read oil pressure on the dash.. does it sound like its from the Front, back, left side, right side of the motor or the center? if it changes with RPM then you can know it is most likly rotational... Alternator, PS pump, Idler, Tensioner would be easier to hear from the front.
Last edited by RedZMonte; Jun 26, 2013 at 06:48 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If you power brake the car and rev the engine, maybe you can use a mechanics stepescope and PIN POINT the exact area on the engine drivetrain.
Pull the valve covers and look for a damaged rocker. Look for tiny needle bearings and a rocker that looks cocked or loose.
The OEM GM rockers can and do puke out the rocker needle bearings and the valve train will complain.
BC
Pull the valve covers and look for a damaged rocker. Look for tiny needle bearings and a rocker that looks cocked or loose.
The OEM GM rockers can and do puke out the rocker needle bearings and the valve train will complain.
BC
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 960
Likes: 1
From: Trussville AL
Thanks Bill. I forgot that my rockers had the Comp Cams trunion upgrade. The noise was there before and after the upgrade but is steadily getting worse. I just pulled both belts and started the car and still get the noise. So no accessory problem. I'll try the power brake trick with a scope shortly. Then I'll pull the valve covers and have a look at the rockers.
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 960
Likes: 1
From: Trussville AL
Pulled the valve covers and everything looks fine there. Even with the Comp Cams trunion upgrade the rockers have very small side to side movement when there is no load on them. I'm beginning to think that is my noise.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Some things to look at and examine.
1. Check the rocker perches that the rockers sit on and make sure that they are not worn and damaged/
2. Get a pushrod checker and make sure that you have the orrect length pushrods and proper preload.
Bill
1. Check the rocker perches that the rockers sit on and make sure that they are not worn and damaged/
2. Get a pushrod checker and make sure that you have the orrect length pushrods and proper preload.
Bill
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Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 960
Likes: 1
From: Trussville AL
Didn't touch the car today so no updates. Tomorrow I'm putting the valve covers back on and taking it to Speedsouth for their opinion on the noise and talk to them about a cam, headers and a tune and some other goodies.
Racer
Joined: Nov 2008
Posts: 257
Likes: 0
From: Plano IL