OT - help settle a car engine diagnostic dispute

Royse

Well-known Member
Looking at a 2001 Pontiac Grand Prix with a 3800 Series II engine.
(Not to buy, trying to "guess" what's wrong with it)
When we start the engine, it hammers and bangs from the
transmission end of the engine, then stops making those noises.
About the time it stops making those noises, it starts squealing.
Internally. Serpentine belt has been removed.
I say it has/is spinning a bearing so it is about junk.
My buddy says it isn't smoking and has good oil pressure so that can't be it.
BTW, when it rolled in here it had 7000 miles on the last oil change.
Regular oil, not synthetic and it was a quart and a half low.
That oil smells burnt to both of us.
Like I said, we're essentially guessing since we haven't taken anything apart.
I know you can't see it or hear it, but what's your opinion?
 
Royse, can you take a wooden broom handle against your ear and narrow it down between the lower end of the motor (crank) as opposed to the top (cam)?
 
They are bad to gunk up the engine the gunk stops up the oil pump pick up,,, if you catch it soon enuff you can clean up the pan and hope for the best if not its toast,,, Sounds like its time to call in the family...

I have never seen it but have read were they were bad to wipe out a cam bearing....

I would grind it into sausage :D
 
(quoted from post at 21:38:12 07/24/13) Royse, can you take a wooden broom handle against your ear and narrow it down between the lower end of the motor (crank) as opposed to the top (cam)?
I have a mechanic's stethoscope, but it's so bad I'm afraid to run it very long at all.
I guess I will though. Heck, if it puts a window in the block we'll know for sure!
 
Does the trans work normally? Torque converter internals
or flex plate could be broken. Does it have a PCV valve in
it? That will cause a squeal when it is running if it is left
out. Have you checked the starter drive? I just had one two
weeks ago that had a broken drive that allowed the pinion
to bounce off the flywheel when running. That could also
be your squeal, overrunning clutch on drives can squeal if
stuck in. Never condemn an engine until exhausting all
possibilities.
 
(quoted from post at 21:42:26 07/24/13) They are bad to gunk up the engine the gunk stops up the oil pump pick up,,, if you catch it soon enuff you can clean up the pan and hope for the best if not its toast,,, Sounds like its time to call in the family...

I have never seen it but have read were they were bad to wipe out a cam bearing....

I would grind it into sausage :D
Hobo - thanks. I was hoping you'd chime in too.
I listened to this engine run last week and heard no noises at all.
Last week I didn't know about the age of the oil, etc.
That's part of the debate that I forgot to put in my original post.
It's an "all of a sudden" failure.
BTW, when I pulled the dipstick today, there was a bit of sludge on it.
Not gobs, but a clump I could easily see.
Last rights are probably in order.
 
I don't have Mitchell on my home computer, so I can't look it up, but is seems to me that the 3800 series 2 used a balance shaft down in the v above the cam shaft. I remember some issues with the balance shaft and having some real strange noises.
 
(quoted from post at 21:51:49 07/24/13) Does the trans work normally? Torque converter internals
or flex plate could be broken. Does it have a PCV valve in
it? That will cause a squeal when it is running if it is left
out. Have you checked the starter drive? I just had one two
weeks ago that had a broken drive that allowed the pinion
to bounce off the flywheel when running. That could also
be your squeal, overrunning clutch on drives can squeal if
stuck in. Never condemn an engine until exhausting all
possibilities.
Yes, trans works normally, including overdrive.
It "think" it has a PCV valve in it.
I'm certain that no one took it out in the past week.
I have not checked the starter drive.
It doesn't sound like its hanging, but I have not checked it.
The hammering at start up and the squeal sound deeper than
that to me, but I am asking for opinions without you having the
benefit of actually hearing it, so I do appreciate the advice.
If you know of a good way to isolate that, without tearing it all
apart or buying new parts I'm all ears!
I will tear it apart before I condemn it, but I'm thinking of taking
the oil pan off, which is not a real easy task on these cars either.
 
(quoted from post at 22:20:53 07/24/13) I don't have Mitchell on my home computer, so I can't look it up, but is seems to me that the 3800 series 2 used a balance shaft down in the v above the cam shaft. I remember some issues with the balance shaft and having some real strange noises.
Back to the stethoscope I guess.
I wonder if my camera will pick up the sound well enough for you
all to hear what I'm hearing. Maybe I'll try that tomorrow.
 
have you tried a known good mechanical oil gauge on it? i've never seen a bad bearing with good pressure unless it spun and blocked oil hole.
 
Every time I have had an engine spin a bearing, it lost oil pressure. Of course, as they say,there is always an exception. There are a lot of good suggestions offered here, problem is, it is time consuming. Now that you have all of us wondering,let us know what you find.
 
Make sure it isn't the vibration dampener, I have changed a few on 3800's. They hammered so bad you couldn't stand to listen to them!!
 
Royse:

DO NOT restart the engine, even for diagnostic
purposes.

7000 miles since the last oil change, sludge on
the dip-stick, burnt smelling oil, hammering noise
at start-up followed by squealing sounds. This all
tells me that the engine is about ready to "throw
a rod".

Pull that engine NOW! If that engine lets loose
while you're doing a diagnostic run, you just got
a boat anchor instead of a possibly rebuildable
engine.

Doc
 
My nephew has been driving a Ford pick up for 2 months with torque converter make similar noise you describe. Very loud.
I think listening in order to narrow it down before pulling the pan. I would think listening underneath without scope and covering transmission converter area and pan with furniture pad type sound damper to see if sound muffels.
 
da.bees:

Sounds like your nephew is in need of a new Flex-plate on his torque converter. A broken flex-plate does make a lot of noise, but those noises are a lot different than from what Royse describes, particularly given the rest of the information as to the condition of the engine.

Doc
 
Make sure the pcv valve and the o-rings are in it. If not they will
make a terrible squealing noise from the crank seals due to full
engine vacuum in the crankcase. I've seen them left out before
after replacing the upper intake manifold. I've seen the balancer
issues also, as another poster mentioned
 
had 2000 lumina, 3100 engine, swore it was bearing issue, but pulled harmonic balancer off front, what a pain, put new on-old showed out of round. Car had 210000 miles on it when daughter totaled it, ran quiet as a mouse after dampner change
 
I'd look at the flex plate first, and if that doesn't show you anything, then pull the oil pan. I'd say you're 99% likely to find the problem by taking this approach.
Good Luck and God Bless
 
Hey Royse.

Almost sounds like a failed oil pump. You say your buddy knew it had good oil pressure but idiot lights and factory oil press gauges can be wrong.

Don't know about this engine but some of them you can check by removing the distributor and spinning the pump with a hand drill.

Good luck,

Brad
 
(quoted from post at 15:36:14 07/25/13) had 2000 lumina, 3100 engine, swore it was bearing issue, but pulled harmonic balancer off front, what a pain, put new on-old showed out of round. Car had 210000 miles on it when daughter totaled it, ran quiet as a mouse after dampner change

If it is a balancer issue all he has to do is try and move the belt (engine off) he will see the balancer turn about 1/4 of a turn with no resistance before the safety/lock on the ballancer catches..

And yer they will rattle like ell...

I have see the PCV valve scream also...
 
Thanks to all of you who have offered some advice on this 3800.
I have a little more info, but not a lot. I only had an hour or so
to work on it after work tonight.
I can't detect any movement in the dampener.
The PCV valve is there. I took it out and it is coated with the
same burnt smelling motor oil, but it does rattle freely.
I have not hooked a mechanical oil pressure gauge to it.
I also haven't gotten to take a look at the flex plate yet, I need
it out of my way for another (prior scheduled) job this weekend.
When the car quit, it was doing 40 mph on a straight stretch of road.
It would then start, but squeal and die as soon as you let off the gas.
Would the flex plate cause a symptom like that?
Today after cooling all night, it started with a bit of a clatter,
but then quieted right down, made no noise at all.
No knocking, no squealing, nothing out of the ordinary.
I ran it maybe 5 minutes total, then I shut it down and put the
serpentine belt back on to back it out of the shop out of my way.
Backed it out at idle. Never touched the gas.
By the time I got 40 feet to where I was going the squealing
had started and it died on it's own.
I didn't try to restart it.
Monday I'll get the front jacked up and see what I can see, just
thought I'd give you all an update and say thanks for the help!

Dr. Walt, I hear you on not running it, but I'm not going to rebuild it.
The local junk yard has a 3800 with 40K miles on it for $600.
The car it is in was rear ended. If I need a rebuild, I think I'll go that route.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top