98 trans am ls1 loud knock
Thread Starter
Teching In
Joined: Feb 2013
Posts: 20
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From: California
98 trans am ls1 loud knock car has 116,000 miles
couple days ago it started a loud knock
when first started cold its barely noticeable whether idle or driving
once warm its noticeable at idle and driving
if i take off from a red light it knocks loud,then it kinda fades away for about 20 seconds and starts again like it fades when the automatic transmission shifting higher gear.then when im cruising at a set spednits constant and its loud.
freeway driving say im doing steady 60 its knocking,so i speed up to 75 and it doesnt knock at all / steady 75 its knocking loud / accelerating from 75 to 90 once again i cant hear any knock / steady pace at 90 its knocking loud again
i checked my oil when i heard the knock and it barely registered on the dipstick had to add 3 quarts
i dnt think its piston slap becuz it doesnt stop when engine gets warm,when its warm it gets worse
the knock is coming from what sounds like the passenger side valve cover or under the intake manifold area
there is no loss of power
dropping the oil pan would be the first thing to do correct?
couple days ago it started a loud knock
when first started cold its barely noticeable whether idle or driving
once warm its noticeable at idle and driving
if i take off from a red light it knocks loud,then it kinda fades away for about 20 seconds and starts again like it fades when the automatic transmission shifting higher gear.then when im cruising at a set spednits constant and its loud.
freeway driving say im doing steady 60 its knocking,so i speed up to 75 and it doesnt knock at all / steady 75 its knocking loud / accelerating from 75 to 90 once again i cant hear any knock / steady pace at 90 its knocking loud again
i checked my oil when i heard the knock and it barely registered on the dipstick had to add 3 quarts
i dnt think its piston slap becuz it doesnt stop when engine gets warm,when its warm it gets worse
the knock is coming from what sounds like the passenger side valve cover or under the intake manifold area
there is no loss of power
dropping the oil pan would be the first thing to do correct?
What kind of oil pressure do you have.
My first step would be pull the oil filter and cut it open.
See if you have any bearing material in it.
It will a shiny metallic substance.
Good luck.
My first step would be pull the oil filter and cut it open.
See if you have any bearing material in it.
It will a shiny metallic substance.
Good luck.
Thread Starter
Teching In
Joined: Feb 2013
Posts: 20
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From: California
the oil pressure i will check and post later today
the bearing material if this substance were to be there what would it be from bearings?
im sure everyone here loves there ls1's,this is my 1st,i had a 95 trans am lt1 that got totalled.i paid 9,000 cash fot the ls1 every penny i had,wasnt expecting this to happen after only having the car bout 5 years,i dnt have much money but without this car i will be out of a job,place to live,and i would have to put school off.
i really hope whatever it is i can get it fixed for around 700
thanks
the bearing material if this substance were to be there what would it be from bearings?
im sure everyone here loves there ls1's,this is my 1st,i had a 95 trans am lt1 that got totalled.i paid 9,000 cash fot the ls1 every penny i had,wasnt expecting this to happen after only having the car bout 5 years,i dnt have much money but without this car i will be out of a job,place to live,and i would have to put school off.
i really hope whatever it is i can get it fixed for around 700
thanks
Sounds like a rod bearing to me. You should always have a back up car. Even if it's a $500 Cavalier or something. Cars break. Every car. If usually isn't cheap to fix if you can't do it yourself and be without the car while you are gathering parts. I have a repair shop so I see what happens. I own 3 daily drivers because you never know what's going to happen.
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From: w.mass
Motor needs to come out of the car and at VERY minimum the bottom end will need to be rebuilt , If its a rod knock which it does sound like..Might wanna start calling Bone yards to see if you can find a shortblock (keep costs down ) or a drop in long block with decent miles....The bottom end can be fixed dont get me wrong but it might end up costing you more in the long run then just replacing the engine with a used one....
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Joined: Nov 2004
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From: Tampa FL
A 98 block with 116k miles and a spun Bering is a boat anchor. The 98 ls1 blocks are super thin walled and can't even be honed. Try and find a running truck 6.0 motor and swap your heads, intake and cam over and drop it in the place of the Ls1.
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Sounds like a rod bearing to me. You should always have a back up car. Even if it's a $500 Cavalier or something. Cars break. Every car. If usually isn't cheap to fix if you can't do it yourself and be without the car while you are gathering parts. I have a repair shop so I see what happens. I own 3 daily drivers because you never know what's going to happen.
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Teching In
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From: California
my car is not a boat anchor,the previous owner was a female,i got it at 80,000 miles,the car was and is in pristine condition,i get compliments all the time how good my car looks,ive always changed oils,fluids,etc..
the only thing that went bad was the water pump since ive had it.the car up until a few days ago engine was perfect no signs at all of anything closely to going bad.
Even with the loud knock there is no loss in power.
i dont understand how this happened so fast
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the only thing that went bad was the water pump since ive had it.the car up until a few days ago engine was perfect no signs at all of anything closely to going bad.
Even with the loud knock there is no loss in power.
i dont understand how this happened so fast
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[/IMG] Last edited by gsxrjunkie750; Feb 17, 2013 at 04:33 AM.
Teching In
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From: w.mass
I dont think he was saying your "car" was a boat anchor just the engine block..Your car looks alright , but the cost of having the motor fixed is far more then buying a truck motor like he was saying and just dropping it in...The walls are thin in those years ls motor from what i have read , it's a crap shoot on honing or over boring the cylinders.Plus the cost, $700 dont get you very far with these motors unless you can do all the labor yourself...The old school sbc you buy a dime a dozen for a driver motor and just drop in it and be cruising the same day.LS motor are expensive to fix and upgrade, but worth it.....
The rod knock can just happen out of the blue just like it did , metal fails at some point and unfortunately its always when you need it to NOT happen...
Have you confirmed that it is a rod knock?
The rod knock can just happen out of the blue just like it did , metal fails at some point and unfortunately its always when you need it to NOT happen...
Have you confirmed that it is a rod knock?
A rod knock doesn't usually come and go, it's always constant. It will get louder during acceleration and that's when the knock goes away for you. I have a feeling there's a collapsed lifter or possibly another issue in valvetrain. It could even be a cracked flex plate between the motor and trans. Also something could be loose in the exhaust system, or you have a bad cat convertor or even a loose heat shield.
Last edited by RedHotG8; Feb 17, 2013 at 06:32 PM.
TECH Enthusiast
Joined: Nov 2004
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From: Tampa FL
my car is not a boat anchor,the previous owner was a female,i got it at 80,000 miles,the car was and is in pristine condition,i get compliments all the time how good my car looks,ive always changed oils,fluids,etc..
the only thing that went bad was the water pump since ive had it.the car up until a few days ago engine was perfect no signs at all of anything closely to going bad.
Even with the loud knock there is no loss in power.
i dont understand how this happened so fast
[IMG][/IMG]
[IMG][/IMG]
the only thing that went bad was the water pump since ive had it.the car up until a few days ago engine was perfect no signs at all of anything closely to going bad.
Even with the loud knock there is no loss in power.
i dont understand how this happened so fast
[IMG]
[/IMG][IMG]
[/IMG] Thread Starter
Teching In
Joined: Feb 2013
Posts: 20
Likes: 0
From: California
I dont think he was saying your "car" was a boat anchor just the engine block..Your car looks alright , but the cost of having the motor fixed is far more then buying a truck motor like he was saying and just dropping it in...The walls are thin in those years ls motor from what i have read , it's a crap shoot on honing or over boring the cylinders.Plus the cost, $700 dont get you very far with these motors unless you can do all the labor yourself...The old school sbc you buy a dime a dozen for a driver motor and just drop in it and be cruising the same day.LS motor are expensive to fix and upgrade, but worth it.....
The rod knock can just happen out of the blue just like it did , metal fails at some point and unfortunately its always when you need it to NOT happen...
Have you confirmed that it is a rod knock?
The rod knock can just happen out of the blue just like it did , metal fails at some point and unfortunately its always when you need it to NOT happen...
Have you confirmed that it is a rod knock?
Thread Starter
Teching In
Joined: Feb 2013
Posts: 20
Likes: 0
From: California
A rod knock doesn't usually come and go, it's always constant. It will get louder during acceleration and that's when the knock goes away for you. I have a feeling there's a collapsed lifter or possibly another issue in valvetrain. It could even be a cracked flex plate between the motor and trans. Also something could be loose in the exhaust system, or you have a bad cat convertor or even a loose heat shield.
how exectly or yet what are the steps in finding out exactly the problem?
thanks.
btw how can something loose in the exhaustsystemor a bad cat make a loud knock?
can anyone tell me what the car is worth as is?
