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J

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Hello everyone,
I have a 91 Caprice with a 305 V8 with 68,000 miles on it. I've noticed a slight knock only at idle after the car has warmed up. When the car is in drive and even in WOT I do not hear any knocking at all and power is strong once the car is warmed up. Does anyone know what may be causing this knocking? Should I worry about it?
Thanks,
Fred
 
S

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Sounds a lot like the time I spun a bearing in my 400sbc ('76 Caprice wagon) about a million years ago. I would not run it hard (or at all) until you get a real diagnosis.

good luck,
-Douglas
 
M

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Probably worn rod bearings. Try running a heavier weight oil to see if that helps. Could be a weak pump. Get an aftermarket gauge to see how low the pressure drops to.
 
J

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Thanks for the replies.

Why would the knock only be heard at idle? Again at WOT the car sounds fine. I did just change the oil....I wonder if that's a factor?
Hope evryone's having a good Thanksgiving.

Thanks again,
Fred :cool:
 
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at idle you oil press. is at its lowest, did you put a different weight of oil in, (5w-30 instead of 10w-30 for example) ?
 
V

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I have a question. What is the deal with some TBI motors lasting for way over 100,000 miles and other TBI engines having problems before 100,000 miles. My 95,000 L03 tapps and dosent sound healty at WOT. It has done this since the car has 70,000 on it. Also My engine hates the cold. If its 30 degrees out side it dosent want to start and somtimes seems like its almost going to stall.
 
J

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at idle you oil press. is at its lowest, did you put a different weight of oil in, (5w-30 instead of 10w-30 for example) ?
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Thanks for the info. As for the oil, I put 10w-30 in it.
Thanks,
Fred
 
J

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have a question. What is the deal with some TBI motors lasting for way over 100,000 miles and other TBI engines having problems before 100,000 miles. My 95,000 L03 tapps and dosent sound healty at WOT. It has done this since the car has 70,000 on it. Also My engine hates the cold. If its 30 degrees out side it dosent want to start and somtimes seems like its almost going to stall.
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Sorry to hear that Brian...I hope this is not what's in store for my Chevy since I really love this style car and I just bought mine seven months ago after years of dreaming about owning one.

Good Luck,
Fred :eek:
 
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The difference depends on which day of the week the car left the assembly line.
My father always said to never buy a car that was built on a Friday or a Monday.
On Fridays they are rushing to get done to get out for the weekend, and Mondays there working with a hangover.

My old 92 305 Caprice is still runing with no engine repairs yet, currently with 240,000+ miles on it. I guess it was built on a Wed.

I think my current 96 started down the assembly line on a Friday and finished up on a Monday. :D
 
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Also, my 92 has always had Penziol 10w30 with new filter every 3 thousand miles.

Also I live out in the rural county about 15 mins from the city, so little short runs to the minimart are none existant. The car always gets warmed up and cursies at 55-65mph before its shut down again.
 
J

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Has anyone tried those restorers or engine oiltreatments that you pour into your crankcase? They are supposed to "restore worn engines" and quiet down knocking and tapping engines. Anyone know if they work? Also will it harm the engine if I try it?

Thank you,
Fred :confused:
 
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305's arent known to be a "high milage"motor..there known to start giving signs of giving up at around 100k really.... my fathers old truck had a 305, around 120k, it REALLy started to give in.... :rolleyes:
 
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I had a 305 in a 4X4 I beat on severely at 150K the compression was fairly even at 135-140. Just to give an idea how rough I was in 20K I went through two clutches and the maual tranny needed work twice, frame was cracking around the rear shock mounts.......
 
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Jon, I beg to differ on the 5 liter motors not going the distance.

I think the lowest mileage my family got on one of these is 170K miles. I gave away an '83 wagon (too many cars, never drove it, and a very rough interior/exterior, insurance/tags were due) to be in a demolition derby) at 245+K miles (it still started instantly and ran as hard as it did new, which, granted, was not very hard at all. It did eat its 4-speed tranny regularly at around every 110K). The speedometer worked fine, but the odometer failed at the 145K mark (after going around once) about 2 years before I gave it away) We were not kind to these motors. Over the years I had talked to quite a few people and they all (as I recall) had huge mileage on them.

-I am done now.

Douglas
 
E

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Discussion Starter #16
<BLOCKQUOTE>quote:</font><HR>Originally posted by jerseyfred:
Hello everyone,
I have a 91 Caprice with a 305 V8 with 68,000 miles on it. I've noticed a slight knock only at idle after the car has warmed up. When the car is in drive and even in WOT I do not hear any knocking at all and power is strong once the car is warmed up. Does anyone know what may be causing this knocking? Should I worry about it?
Thanks,
Fred
<HR></BLOCKQUOTE>

hey fred,

take the car to your local transmission shop and have them check the flex plate for cracks,
or, pop the TC dust cover off the bottom of the tranny and check yourself.

it would be easier if the tranny shop does it for you.

a cracked flex plate will cause a vibration at idle that resembles a low engine bearing problem....as you bring the rpms up, the noise/knocking will go away [or sometimes gets worse] due to stress being relieved from the broken or cracked area.

could also be the pump in the TC going bad.

all i'm saying is, dont rule out the transmission as it is connected directly to the low end of your motor.

good luck,
ED
 
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Discussion Starter #17
On the derby action, well, let us just say that it is done too. It did not make a second race.

-D
 
T

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<BLOCKQUOTE>quote:</font><HR>Originally posted by 96greengrey:
Also, my 92 has always had Penziol 10w30 with new filter every 3 thousand miles.

Also I live out in the rural county about 15 mins from the city, so little short runs to the minimart are none existant. The car always gets warmed up and cursies at 55-65mph before its shut down again.
<HR></BLOCKQUOTE>

Hey, hey, somebody from my former corner of the earth.

I crossed that bridge one time after they closed 24 for stress cracks or something. We were going to a 'cards game in my uncles LTD wagon. He had a lead foot and was flying over that bridge. I was glad to get on solid ground again.
 
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Discussion Starter #19
<BLOCKQUOTE>quote:</font><HR>Originally posted by eds9c1:
hey fred,

take the car to your local transmission shop and have them check the flex plate for cracks,
or, pop the TC dust cover off the bottom of the tranny and check yourself.

it would be easier if the tranny shop does it for you.

a cracked flex plate will cause a vibration at idle that resembles a low engine bearing problem....as you bring the rpms up, the noise/knocking will go away [or sometimes gets worse] due to stress being relieved from the broken or cracked area.

could also be the pump in the TC going bad.

all i'm saying is, dont rule out the transmission as it is connected directly to the low end of your motor.

good luck,
ED
<HR></BLOCKQUOTE>

Have to agree with ED on this one. If the knock goes away when the car is in gear, (try Drive & Reverse) then the flex plate could be the culprit. It's definetely cheaper than a motor and easier to fix.

Check it out!



Jerry
 
J

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Discussion Starter #20
hey fred,
take the car to your local transmission shop and have them check the flex plate for cracks,
or, pop the TC dust cover off the bottom of the tranny and check yourself.

it would be easier if the tranny shop does it for you.

a cracked flex plate will cause a vibration at idle that resembles a low engine bearing problem....as you bring the rpms up, the noise/knocking will go away [or sometimes gets worse] due to stress being relieved from the broken or cracked area.

could also be the pump in the TC going bad.

all i'm saying is, dont rule out the transmission as it is connected directly to the low end of your motor.

good luck,
ED


--------------------------------------------------------------------------------

Have to agree with ED on this one. If the knock goes away when the car is in gear, (try Drive & Reverse) then the flex plate could be the culprit. It's definetely cheaper than a motor and easier to fix.

Check it out!

I think this may very well be the problem. The knock goes away when in drive but there is a slight buzzing noise (like an electric razor) when idling in drive or reverse (such as when waiting on line at a drive thru. Any idea on cost if it is the flex plate? Also, is it dangerous...will it strand me?

Thanks for all the responses and support. I love my Caprice but don't have much money right now and would like to keep it running.

Thanks,
Fred
 
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