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Old 03-11-2007, 02:28 PM
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Please help - Car sounds like a chopper!

Okay folks, I think something is seriously wrong with my car, specifically my engine. 1994 325is 170,xxx miles.

I'll admit, I was late on getting my oil changed, and i do have 170,000 miles on the car, but I didn't wait THAT long, and besides.. it had made a small tick which I always thought were the hydraulic lifters 'tapping' for over a year and a half maybe two. More oil always made it go away.

Past year, slowly got worse, but i attributed it to oil leak thus low oil maybe. So in the past 3 days, its gotten ALOT worse, like it literally sounds like an old weak harley davidson between 2k and 4k rpm.

So i got the oil changed today. they put in 6 quartz, helped a TINY bit.. still loud and obnoxious; idle is still dipping up and down around the 700rpm area, engine still stalling out at every other stop light requiring a restart. What gives!!

I even remembered these engines take hella oil and put 3/4 of a 7th quart, and no difference. Its not my oil .. *gulp*

What the hell could it be? It's clearly coming from under the hood .. engine area.. i can still rev to redline, infact, past 4.5k rpm it sounds "okay". But in city driving it is constantly in that 2k to 4.5krpm and thus sounding like a damn motorcycle.

Could a chain be loose, or off? Could my valves need 'adjusting'? I dont think its the spark plugs, i put em in at 100k miles. Could it be that i have thrown a rod or bent a valve or some crazy mess and my engine is screwed? If so .. why can I redline without hesitation from engine?

If anyone reading this has ever heard of this happening please let me know what you know, I dont want to have to junk the car, but its worth so little, heavy duty engine repair may be too expensive to get done. We shall see what it is, I know I just gotta take it in one day and get a diagnosis, but I thought i'd see if anyone has a lucky guess here before I do that. Thanks ahead of time.


This is how i feel about it..
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Old 03-12-2007, 11:09 AM
 
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can you post a sound file?

it could be a cracked manifold/bad manifold gasket or it could be only an internal tick.

does it vary with RPM?

does it vary with throttle pressure?
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Old 03-12-2007, 12:58 PM
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yes it varies wildly.

when i press the gas pedal to make the rpms rise, it makes the noise.

if im at an idle, its quieter, but still loud enough to know something is def wrong.

the noise is definantly coming from the engine block. sounds like the top of the engine.

the noise is worse between 2,000 and 4,500rpms. its also worse when im in 1st or 2nd gear as opposed to 3rd or 4th, on the automatic.

at high rpm to redline it doesn't sound as bad, but definantly doesn't sound normal. it actually sounds meaner, like it has more displacement or something in the higher rpms.

theres an ever slight delay between me pressing the gas and the noise becoming noticably louder as a result. also, when i take my foot off of the gas pedal, the noise 'slows down' as if whatever's making the noise is doing less rpms (over the course of a second or two), and then it steadies out at the quieter yet still obnoxious idle sound assuming i dont touch the pedal.

took it out for a spin today to see if the oil change needed time to change the engine's sound, which it didnt. People could hear it at least 30 feet away from the car, standing on a sidewalk or parking lot. the reason i knew is because i was watching for people to look so i could see how far the nasty noise actually travels lol. one guy did the neck cut hand signal with his hand, i guess implying that my engine is dead or dying.

Last edited by runetang; 03-12-2007 at 01:03 PM.
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Old 03-12-2007, 02:13 PM
 
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sounds to be unrelated to oil.

if i had to guess its a damaged/cracked exhaust manifold or collector or a totally blown manifold gasket.

if you rev the motor with the hood open do you see exhaust smoke>?
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Old 03-12-2007, 02:16 PM
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sounds to be unrelated to oil.

if i had to guess its a damaged/cracked exhaust manifold or collector or a totally blown manifold gasket.

if you rev the motor with the hood open do you see exhaust smoke>?
BIG +1! It's probably cracked, causing a bad O2 sensor reading (your stalling issue)
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Old 03-12-2007, 09:12 PM
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When I rev it with the hood open I see no smoke.

Hmm .. I was thinking it had something to do with the engine head because theres a fair amount of oil gunk collected all around where the head cover screws onto the top of the block or w/e. with the hood open, the "tick tick tick" noise that gets super fast when the gas is pressed seems to be coming from the top of the engine .. but its not just a tick, its louddd. a knock maybe. but not a deep sound, clearly coming from the top i think.

I wish i knew. If it was just what you guys are thinking, i'd be out there driving it with no worries, its just loud then right? But if its an engine problem, driving it is extremely bad.
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Old 03-12-2007, 09:24 PM
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You've already gotten some great advice. If you don't have the means to diagnose this yourself, take it to an exhaust shop and have them inspect the exhaust manifolds for leaks. It sounds like that is your issue. Happened to my e36 m3 at 100k.
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Old 03-12-2007, 10:53 PM
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did you notice a slight hesitation in the gas pedal occasionally when accelerating, or starting to, while already moving, when you had a manifold leak?

i sound a bit skeptical because the noise really does sound like its emanating from the engine and is metal on metal in nature but then again, it may be the exhaust because would engine troubles really make an engine that much louder, i mean .. besides making it sound bad.

edit: plus, when i got the oil changed, while it was just a regular oil change place and not a bmw specialist, u'd think they woulda told me if it was a manifold leak. but they didnt say a word about why it was so damn loud and obnoxious, i know the possibility of them having no idea is pretty real..
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Old 03-13-2007, 08:19 AM
 
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the top end of an engine can produce a tick from the lifters or valves.. but anything near the volume that you are describing would not allow the car to run for long.

again...i really think this has the potential of being an exhaust manifold.

i will keep thinking that until you give me more to go on.

for the love of the car.. please just have a look.
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Old 03-13-2007, 09:21 AM
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okay, i went and looked myself but didnt take it in yet, lack of funds

i couldnt see or feel any holes or rust-tears or anything like that, but then again you'd have to be underneath the car to get the best look. it looks rusty though? maybe a gasket that goes inbetween it and the cat converter is messed up / loose, or maybe theres a hole i cant see.

i noticed that the ticking coming from the engine itself may not be that loud, and part of that noise is the engine fan just being noisey. It doesnt get obnoxious sounding until i floor the pedal even just a little (like 3-4krpm), and like i was saying, even though at idle it def sounds like a knock, that could just be the steady out-flow of exhaust through the leak making a deceptive sound.

since everyone thinks its the same thing, ill just let this thread go into history.
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Old 03-13-2007, 09:21 AM
 
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It would be helpful if you could post a wav file with the sound, as we are trying to imagine what it sounds like. You mention motorcycle, which suggests that it is a popping exhaust sound, which makes folks think of cracked exhaust manifold or badly leaking exhaust gasket. You could also have a leak backiing up though the air injection system on the emission control. Either of these leaks should be easy to locate with the hood up and the engine running.

If it is more of a chatter, I vote cam chain.

If it is more of a metalic clicking, valve adjustment/actuation.

These engines are not known for failing rod bearings unless it was run completely out of oil at some time in its life. If it has a failed rod bearing, it is engine swap time.
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Old 03-13-2007, 10:36 AM
 
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Quote:
Originally Posted by runetang View Post
okay, i went and looked myself but didnt take it in yet, lack of funds

.
not sure where you are, but a diagnosis will be at most 30 minutes... so even at the dealer, about 50 bucks

Quote:
Originally Posted by runetang View Post
okay, i went and looked myself but didnt take it in yet, lack of funds

i couldnt see or feel any holes or rust-tears or anything like that, but then again you'd have to be underneath the car to get the best look. it looks rusty though? maybe a gasket that goes inbetween it and the cat converter is messed up / loose, or maybe theres a hole i cant see.
.
i doubt the naked eye could detect it from the top.... it will be a hairline, most likely seen from below and would have black soot around it.

Quote:
Originally Posted by runetang View Post
i noticed that the ticking coming from the engine itself may not be that loud, and part of that noise is the engine fan just being noisey. It doesnt get obnoxious sounding until i floor the pedal even just a little (like 3-4krpm), and like i was saying, even though at idle it def sounds like a knock, that could just be the steady out-flow of exhaust through the leak making a deceptive sound.
.
if it were further down the exhaust than the manifold, it would be less distinctive pops.. more of an overall rasp.

Quote:
Originally Posted by runetang View Post
since everyone thinks its the same thing,
based on the minimal info provided yes.. it seems like we do. .. a more thorough inspection / sound file etc will yield better answers.

i think that given what you've told us, we have been pretty clear about the possible causes.

Quote:
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ill just let this thread go into history.
your call, but the car is not fixed yet. its now on you to either get an inspection or give us more info.

if it is an internal engine knock from the bottom end, it will blow up soon... no helping it.

if its a top end noise, fix it before you blow it.

if its a manifold/gasket etc, it will get alot worse and does stand to cause further damage.

if money is a concern, fix it before it breaks more stuff.

i'll now quote the great forrest gump:

"that's all i have to say about that"
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Old 03-14-2007, 09:21 AM
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lol. i apologize for no sound clip, however, i do not know how. i reckon i could use a phone and record it as a msg and somehow send that message to myself in an email. or i could have a wireless microphone, which i dont have. all in all its pretty much impossible for me to get a sound clip for yall atm, it wouldve been in the first post b/c i know that would help determine the problem greatly.

as to what Manolito said, now you're sounding more on the money as to what I think it may be due to the sound that im hearing, but it could be two things, engine & exhaust manifold. It's definantly a chatter, a loud obnoxious chatter. not a popping or a bottom end sound, a RAAAAAAAAAAAAGGGGGGHHHHHH!!!!!!!!! *metal rubbing metal repetitiously in a circular sounding motion that increases with the rpms* sound. it decreases with rpms too .. and at the idle, itll just be a slow but moderately loud 'lifter banging' noise. <b>sounds like something is smacking up against something in the head of the engine.</b>

i've been thinking it sounds like a chain that is loose in the engine. whatever it is, i can still drive the car without issue, im just not because it's embarassing and offensive to other ppl's ears.

i'd have already taken it in, but im really really broke at the moment, yea i know i shouldnt own the car. thats why ive been considering getting it fixed and then trading it for an e30 manual.

i know that my sound description is of little help lol. But its like you want to instinctively pull your head back a bit from the hood area when the hood is open and someone presses the gas because its so damn loud.

PS: If i had loud lifters but they weren't a driving problem, would having an exhaust manifold leak make those loud lifters sound like something much worse? Due to the sound escaping from under the hood before going through the muffler etc. That could be it, my lifters could be fine and the exhaust manifold is just making them SOUND extremely bad / loud because .. well .. anything would be extremely loud w/no muffler right, a tick would become a bang right?

Last edited by runetang; 03-14-2007 at 09:26 AM.
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Old 03-24-2007, 01:11 AM
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check the bearings in your accessories ie. water pump, pwer steering. use a long screwdriver handle against your ear and listen to deffrent parts of your head like the vanos sides of the head and stuff like that see if you can here were the noise intensifies or gets quieter. if you think it might be a broken tensioner rev your engine and then listen as you let off the throttle thats when you will hear the chain rattle if its indeed bad. if you had an exhaust leak you should be able to locate it quite easily. do you have any power loss? check your spark plugs see how they look.
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Old 03-24-2007, 11:30 AM
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Sounds to me like you've been overfilling the oil for quite some time. You may have blown the rings on your pistons. These engines do not take hella oil, they take the proper amount of oil as specified by the Bentley and owner's manual.

If you did in fact blow the rings it's time for a rebuild, a new engine, or a new car, your choice.

It could also be something as simple as the plugs, when was the last time you changed them?
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