Is my car knocking, and if so, Why?!
 

The car: a 1990 Pontiac Bonneville LE, 101k on it, 3.8l V6, auto, etc. Never had any problems with it aside from regular maintainance, and the ignition module thingy went out about a month ago, which I replaced.

I came home today and parked my car, and took my parents car, as my girlfriend and I were going out on a date, and their car is nicer. I parked my car on the street so I could pull my parents car out of the driveway. When I came home that night, I parked my parents car, and went outside and started my car to pull it into the driveway. When I started it, I noticed a ticking sound that varied with the RPMS. The car seemed to drive fine all of the 15 feet into the driveway, where I turned it off so I wouldn't mess anything up.

The only things I can think of are that it's really cold outside (for Alabama), it's 32f. Also, the past several weeks I had been noticing that when I took really sharp left corners, the oil pressure gauge would drop considerably during the duration of the turn. It's also had a little bit of a miss to it, but that's probably because the car is still running on the factory plugs and wires (15 years old). Oh, and it's about 500 miles overdue for an oil change, but that is/was scheduled for this weekend.

I checked the oil, it is fine, and there doesn't appear to be metal in it. Oil pressure is reporting fine, just at half on the gauge as usual.

My car was running perfectly when I parked it. Why is it doing this when I go and start it tonight?

The reason this scares me is this: Around July, I bought an identical Bonneville with 132k on it, and 3 months later it spun a rod bearing. The sound it was making before that went down was remarkably similar to this.

What have I done?! Other than running it to redline occasionally, I don't mistreat the car (I don't think?). It's an automatic, so I didn't over-rev the engine, and the oil pressure has always been fine aside from dropping on turns (which it may have done previously and I didn't notice).

If I messed up my engine again, I am going to go kill myself. Wait, my parents are going to kill me first. I cannot afford any major or repairs or a new car, and neither can my parents. My car is vital, if I don't have it, I can't get to school or work, and my life ends.

noisy lifter or a rod knock

Yeah bud.. normal stuff for our engines.

For the Oil Pressure Drop.. It sounds like your oil pan baffle may have broken off. I have made some incredibly sharp turns, and I have never had a drop in oil pressure. I know my baffles are fine, because I replaced my Oil Pan several months ago, and I inspected that thing like an anal bastard. The other thing it could be, is that your are low on oil [which would increase the noise you are experiencing]. Check your oil this morning [without starting the car, of course], and make sure it's in the crosshatched area. You may want to do that oil change today. Grab a Purolator [or Pure One] oil filter, so you know you have a good flowing unit. I also never knew LE's had Oil Pressure Gauges.. but your's goes from 0-80 PSI, correct? And what PSI are you seeing normally, and when you make turns?


-justin

What does a noisy lifter or rod knock mean to me? Rod knock I associate with BAD, BAD, BAD. Is this common?

And yep, I have an oil gauge. It goes from 0-80, and usually rides about 40, when I turn it would sometimes drop to 10-20? Pretty low.

I have got to ride to work, 2 miles away, in this car today. Is it safe to drive?

God, I don't want to tell my dad. He will murder me... I'm so scared right now...

Check the oil. If it's at the proper level, it's okay to drive. Keep the rpms low to be safe. Rod knock could be many things, but the main thing is that there is too much play in the rods, and the noise from the play. Mine had quite a bit of play, and my car was super quiet, so this could be pretty bad if not taken care of. Mine were so bad, that I could move the rockers out of the way to pull the rods out. If I wasn't pulling the heads, all it would have taken was a quick torquing down. If you have a little bit of time, you may want to pull the front valve cover [takes me 2 minutes, but i've done it a million times]. And see how much play there is in the rods, and if the rockers are out of sorts. It is kind of hard to diagnose this problem without hearing it myself, so I am trying to cover all the bases at this point.

The oil pressure going down to 10 or 20 is NOT good. Not good at all. The 40 is normal, I sit at 43, so that's fine. Try your best to keep it above 30, and if you do drop below 30, have the car coast or idle through it. After 5 seconds of it dropping below 30, i'd shut the car off. Low oil pressure will kill your engine. Our ECU's will kill the fuel pump if the oil pressure drops too low, but I don't know what PSI that is. If you can reproduce the oil pressure drop, you also can confirm it is not an intermittant electrical error. But that it is a mechanical problem.


-justin

Just a suggestion - are you at all able to record the sound the car is making for these guys to help you out better? Just a digital camera that can make videos will do. Drop me a PM if you need someone to host it.

Well, I went and checked the oil at dead cold, and it wasn't showing on the dipstick! Last night I checked it while it was warm and it was fine. I added a quart of oil, and let it run for 2-3 minutes and the sound is gone. I feel like an idiot, I know enough about cars to not do stupid stuff like this. I've worked on all my cars since I was 16. What was I thinking?

Did I do any permanent damage? The car runs perfectly silentluy now

Thanks for the advice, I'm going to change the oil as soon as I leave work today, using a Purolator filter, and I've been using Havoline 10w40 oil.

You guys have no idea how much I appreciate your advice. I don't know what I'd do.

l live in Birmingham, AL so it's usually not cold here, it being 32 degrees last night was unusual, it's usually in the 60s during the day, fairly mild.

I pray that I didn't do any serious damage to my engine, but it's running okay for now. I almost had a heart attack this morning.

Watch out if it is rod knock, if left unfixed, wham! Thrown rod.

From the sound of what you have said, you have run your engine with a low oil level.
The knocking was probably caused by your lifters not getting pumped up.
Low oil level caused your oil pressure to drop very low. General rule is 10 psi for every 1000 rpm to maintain proper journal bearing operation.
Low oil pressure will result in metal to metal contact of bearing surfaces, instead of the bearing surfaces being separated by a film of oil.

I hope you normally wait for the engine to fully warm up before loading it up or turning any higher rpms.

You probably caused some engine damage that will result in decreased life for that engine.

I see you have attended the school of hard knocks. :lol:

Thanks for the filter recommendation. I'd been using Fram filters beforehand, which I've been told is not such a good idea. I'll pick up the AC Delco this afternoon.

And yep, I keep it under 3000rpm until the engine warms up, and usually give it a minute or two at idle just in case.

Is there any way to check and tell if there is anything physically wrong with my engine, or is it just a "wait until it goes boom" thing?

Yeah, I live in the dorms at the school of hard knocks unfortunately.

Thanks for the filter recommendation. I'd been using Fram filters beforehand, which I've been told is not such a good idea. I'll pick up the AC Delco this afternoon.

And yep, I keep it under 3000rpm until the engine warms up, and usually give it a minute or two at idle just in case.

Is there any way to check and tell if there is anything physically wrong with my engine, or is it just a "wait until it goes boom" thing?

Yeah, I live in the dorms at the school of hard knocks unfortunately.

It shouldn't go boom.
Just a little wear.
Do a compression test. When you pull the plugs, check their condition.
It your oil level got that low, it was for a reason.
Does it leak out of seals or blow past rings or get sucked up thru the valves ?

How is your vacuum at idle. Steady or does it fluctuate?

How does the engine idle, smooth or rough?
How does the engine pull when under load before it kicks down into a lower gear?

Also when you change your oil, check for oil on the oil pan. If it isn't torqued down in the proper sequance and rating, it'll leak [trust me on this, mine did until I found this magical torque sequence]. Also make sure the oil filter is on tight, and put a little oil on the rubber gasket area to also help prevent leaks. Check around the intake, see if there is any oil puddling in there. My lower intake gaskets let oil through, and I lost 1 quart /3000 miles, and when the car wasn't driven regularly, it went up considerably [I am only 14, and licenseless]. Checking the oil warm doesn't necessarly constitute the actual oil level. The oil level is best determined when most of the oil has settled to the oil pan, thus giving an accurate reading. Usually after 30-60 minutes of letting the engine sit after getting up to running temp will suffice. I usually just check it everytime before I start the car. I'm anal like that. I will dig up a pic of my intake puddle of oil. Just so you have an idea what an oil leak is like.


-justin

Low oil level would also explain the pressure drop in turns. My experience with 3800s is that they use very little oil between changes (I use 10W-30 in Orlando). If you are geeting sudden serious drops in the oil level I would find out why.

Once had a oil sender blow its diaphragm and pump 5 quarts out in under ten miles on the Interstate. Was seven years and 50,000 miles ago, still runs fine.

[quote][I am only 14, and licenseless]. .......Just so you have an idea what an oil leak is like.
[quote]

. :roll:
:poke:

It's running normally now, it ticks VERY VERY SLIGHTLY on cold start for about a minute or so, then quiets down. I've been told it's normal, and I'm just being paranoid at this point.

I changed the oil, it was black as night, but it didn't have any grit or obvious metal flakes on it, and the magnet on the drain plug was clean.

No loss of power, it idles smooth as silk (or as smooth as a V6 can idle). Sounds like normal. I drove it about 45 miles tonight after I changed the oil, and it performed fine.

You guys rock, I wish I could help people out more, instead of just running here when I have a problem. Thank you so much for all your advice.

Oh, and the oil pressure drop going around corners is gone now. Yeah, I guess it helps when you have oil. I feel like a complete moron, but I learned a lesson about checking fluid levels :oops:.

ok try this change the oil fill with 4 quarts of oil and 1 quart on tranny fluid run it for 500-1000 miles the drain and fill normal be sure to put a new oil filter on also

What will this do for me? Sounds interesting :)

Whoops, thanks 2ksilverbullet. I forgot to post the pics.. :oops:.

I didn't really take any pics originally, but I got one after cleaning it a little, and it still looks like shit. And, I have one of my front valve cover that was pissed on a million times. The oil puddle that was originally there, was about 1.5" deep, black as night oil, and it never went away, just kept coming back. This will just give you an idea. And btw, this is the core reason why I am tearing my engine apart. My porting and stuff.. that's just a "what the hell, why not" type thing.. because I am there, may as well do something good while I am at it.

http://www.geeks-unite.com/IM000436.JPG

http://www.geeks-unite.com/IM000437.JPG


-justin

trans fluid has lots of detergent to clean lifters pushrods and so forth it works i have used it many times

Hmm... I think I may have a use for the 6 quarts of DexIII ATF I have now :) I can use it on more than one occaison, correct? I don't want to just throw this stuff away.


-justin

yea i wouldnt use it regularly but i have used it to get rid of noisy lifter on my G/F's Cutlass 2.8 MPFI and My carbed 2.8 Jeep it work really well

Well, like every other oil change or something throw in this and some wal-mart super tech, so I can really clean out the engine [I would feel better having clean oil come out all the time].


-justin