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Intermittend Engine Rattle

Old 06-08-2005, 08:09 PM
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Default Intermittend Engine Rattle

Anybody ever run into an intermittend rattle in the early Vin L 3800 (this is a '94), it shows up only in gear and under acceleration, even then only between 1500-2000 and 2700-3000 rpm'*, it'* a little worse when cold, oil pressure runs about 40 psi while driving and drops to 20 at idle when warm, it has no noise at idle in park or in gear....car has 134k and has been well maintained.

Any suggestions would be helpful.
Old 06-08-2005, 09:14 PM
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I'm pushing 62psi at idle so I'd call your psi'* low, although within spec.

Sounds ignition related. Pinging?
Old 06-08-2005, 09:55 PM
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When was your last tune up...
Old 06-09-2005, 12:42 AM
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isn't that oil pressure low even when my car had bad pan seal and intake seal it ran about 38 hot
Old 06-09-2005, 01:09 AM
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Check your harmonic balancer/dampener for cracking of the rubber material behind the pulley.
Old 06-09-2005, 02:18 AM
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maybe TC bolts
Old 06-09-2005, 07:10 AM
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Originally Posted by GAMEOVER
maybe TC bolts
Hahaha Experience speaks loudly to some of us... your oil pressure isn't something worry about yet. If you are using 0-30W consider moving up to 5-30W or 10-40W. But don't worry about it.
Old 06-09-2005, 08:31 AM
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Hey Guys, thanks for the tips....I can't remember the last tune up so it seems its probably due for one, I can rule out the balancer because I just had that off to replace crank sensor and it looked ok....I will check the tc bolts tonight.

I've also had someone tell me that the rear bearing for the balance shaft may be causing that...have not found any info on that or any complaints from others.

I'm using 10-30 castrol oil, wondering if oil sendeing unit may be off some, the gauge has a tendency to twitch sometimes, will probably need to hook up mechanical gauge to verify pressure.

Thanks again, will keep you updated
Helge
Old 06-09-2005, 10:27 AM
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Originally Posted by psycho_72653
Hey Guys, thanks for the tips....I can't remember the last tune up so it seems its probably due for one, I can rule out the balancer because I just had that off to replace crank sensor and it looked ok....I will check the tc bolts tonight.

I've also had someone tell me that the rear bearing for the balance shaft may be causing that...have not found any info on that or any complaints from others.

I'm using 10-30 castrol oil, wondering if oil sendeing unit may be off some, the gauge has a tendency to twitch sometimes, will probably need to hook up mechanical gauge to verify pressure.

Thanks again, will keep you updated
Helge
Keep an eye on the balancer, especially below where you park. It'll show tiny bits of rubber and black dust when it starts to go. Forget TC bolts, they don't simply come loose on a car that hasn't had recent trans work. And I've never heard of a balance shaft bearing failure, and quite simply, it'* damn near impossible. That system is way overbuilt.

Check your exhaust. Sometimes a catalytic converter heat shield can fool you if it comes loose and rattles. It can be very RPM dependent, and it might also be the innards of your cat starting to come loose.
Old 06-09-2005, 11:55 AM
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Originally Posted by willwren
Originally Posted by psycho_72653
Hey Guys, thanks for the tips....I can't remember the last tune up so it seems its probably due for one, I can rule out the balancer because I just had that off to replace crank sensor and it looked ok....I will check the tc bolts tonight.

I've also had someone tell me that the rear bearing for the balance shaft may be causing that...have not found any info on that or any complaints from others.

I'm using 10-30 castrol oil, wondering if oil sendeing unit may be off some, the gauge has a tendency to twitch sometimes, will probably need to hook up mechanical gauge to verify pressure.

Thanks again, will keep you updated
Helge
Keep an eye on the balancer, especially below where you park. It'll show tiny bits of rubber and black dust when it starts to go. Forget TC bolts, they don't simply come loose on a car that hasn't had recent trans work. And I've never heard of a balance shaft bearing failure, and quite simply, it'* damn near impossible. That system is way overbuilt.

Check your exhaust. Sometimes a catalytic converter heat shield can fool you if it comes loose and rattles. It can be very RPM dependent, and it might also be the innards of your cat starting to come loose.
will your right about the TC bolts but anything is possible

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