Caravan '89 3.0 Auto+OD, Loud rattling Noise from Engine

HI Guys,
Hope to get some help with my 1989 Caravan 3.0 Mitsubishi, Automatic
with overdrive(3-4 speed? P-R-N-Overdrive-Drive-L). Makes a rattling
noise

I went for a camping trip, about 300Km away. It was fine all the way,
ate a little oil, but i refilled to proper level. On the way back,
somewhere after the last stop ~100Km away from end, on the trafic
lights noticed/heard this bad noise from engine when reached the
city(so at the end really).

It happenes at all revs, mostly between 1-2KRPM, i don't think it is
the transmission, even at park when reved it makes that rattling noise.
I'm pritty sure it is from the engine, possibly the back/passanger side
of the engine.
To describe the noise: it sounds like a bad mufler(you can hear the
combustion intervals), somewhat metalic, low frequency not high pitch,
resonating with revs to the point of ear pluging like in a danceclub
(althought i don't feel like dancing).

I was thinking it might be the timing chain/components OR the
valves/lifters/etc OR Camshaft/Driveshaft/rod bearings.

To bring you up to speed, i had this van for ~2months, it had 282K Km
on it now 284K, rebuilt(somewhat don't have much supporting paperwork
on what was done) engine and transmision at about 200K. When i got it
it had a rusted tiny hole in the oil pan(i replaced) and it had a
rattle onece in a while, which went away after i serviced the van when
i got it(oil & filter & pan, rear pads and drums, drive belt, air
filter, spark plugs, trans oil, removed the dead AC and all components
and other body parts like chrome bumpers rear gate etc) all in all this
van had cost me a total of CND$900(price, parts and registration). I
had another 1989 Caravan 4 cylinder that the trans had died and the
engine was eating oil 1L/100km, it is at the junkers now after 250Kkm,
all the good parts are on this van now.

so what you guys think is wrong with it. Please i need help, don't mind
doing it myself, i'm thinking of going to my old mechanic, which i
didn't see ever since i started doing my own work on the 3-4 cars in
the family.

thanks in a dvance
Ilia

> wrote in message
oups.com...
> HI Guys,
> Hope to get some help with my 1989 Caravan 3.0 Mitsubishi, Automatic
> with overdrive(3-4 speed? P-R-N-Overdrive-Drive-L). Makes a rattling
> noise
>
> I went for a camping trip, about 300Km away. It was fine all the way,
> ate a little oil, but i refilled to proper level. On the way back,
> somewhere after the last stop ~100Km away from end, on the trafic
> lights noticed/heard this bad noise from engine when reached the
> city(so at the end really).
>
> It happenes at all revs, mostly between 1-2KRPM, i don't think it is
> the transmission, even at park when reved it makes that rattling noise.
> I'm pritty sure it is from the engine, possibly the back/passanger side
> of the engine.
> To describe the noise: it sounds like a bad mufler(you can hear the
> combustion intervals), somewhat metalic, low frequency not high pitch,
> resonating with revs to the point of ear pluging like in a danceclub
> (althought i don't feel like dancing).
>
> I was thinking it might be the timing chain/components OR the
> valves/lifters/etc OR Camshaft/Driveshaft/rod bearings.
>
> To bring you up to speed, i had this van for ~2months, it had 282K Km
> on it now 284K, rebuilt(somewhat don't have much supporting paperwork
> on what was done) engine and transmision at about 200K. When i got it
> it had a rusted tiny hole in the oil pan(i replaced) and it had a
> rattle onece in a while, which went away after i serviced the van when
> i got it(oil & filter & pan, rear pads and drums, drive belt, air
> filter, spark plugs, trans oil, removed the dead AC and all components
> and other body parts like chrome bumpers rear gate etc) all in all this
> van had cost me a total of CND$900(price, parts and registration). I
> had another 1989 Caravan 4 cylinder that the trans had died and the
> engine was eating oil 1L/100km, it is at the junkers now after 250Kkm,
> all the good parts are on this van now.
>
> so what you guys think is wrong with it. Please i need help, don't mind
> doing it myself, i'm thinking of going to my old mechanic, which i
> didn't see ever since i started doing my own work on the 3-4 cars in
> the family.
>
> thanks in a dvance
> Ilia
>

Without hearing the noise it could be anything (except a timing chain).
That engine uses a belt.

Glenn Beasley
Chrysler Tech

> wrote in message
oups.com...
> I will try and record it, but what usually failes that can cause this
> kind of noise. I know it could be anything really, just hoping for past
> experience of someone here.
>
> so you say it is a timing belt not a chain? is it the one under the
> plastic cover, almost paralel to the accesory belt?
>
> thanks
> Ilia

Yes, and the water pump is there also
>

well you know how i mentioned this noise sounds like a bad mufler, well
cuz it is.
Went to my mechanic, he helped point out that the noise is from the
exhaust pipe, his words were "the cat converter guts have colapsed and
all that **** hit the mufler"
that's why i hear this low frequency mufler noise at about 1.5KRPM.

Now this brings another question to my mind.
Can i stick any cat converter and mufler in there, the bigger the
better right? I can weld the pipes with my dad, so i'm thinking i go to
junker and get my hands dirty.

Do you guys know if anything other than the pipe diameter and the shape
of the exhaust/cat matters(so as long as it fits and was made for a
large engine like mine V6 it should be ok, right?)?

thanks
Ilia

Ok another follow up, hope this helps someone with same problem.
Basically the noise was comming from the downpipe of the exhaust. I
believe that the mufler was "cloged" so it would create back pressure
which resulted in loud noise in the downpipe. I confused it with the
valves malfunctioning because the backpressure was effecting the
clearing of the cylinders on the up stroke from exhaust, so the "booms"
were prity high in the exhaust channel.
Lucky me, my mechanic was very close to identifying the problem.
I went to a junk yard(for the first time), it is like going on a
vacation for me, i loved the place something magical in the air there.
anyway took off a muffler from a ~1992 caravan 3.3L(apperantly the
junkyard removes the catalitic as a recycling process, non of the cars
ha a catalitic on them), cost me CND$20, even had the u clips on
it(didn't get charged), and lucky me the catalitic was fine in my
car(didn't colapse like my mechanic expected).
Went with my dad to his work, he welded the new mufler, patched a
couple of holes, made a new bracket for this slightly bigget mufler, i
installed everything and helped here and there with the cutting and
drilling and holding.
and presto noise is gone, car is quite as was before.
by the way Canadian tire was quoting me ~$500(for new exhaues from cat
to pipe, and mufler alone is $100).
So do the work yourself and you will save.
thanks for your attention and help guys, i like this google groups
thing.
Ilia

wrote:
> well you know how i mentioned this noise sounds like a bad mufler, well
> cuz it is.
> Went to my mechanic, he helped point out that the noise is from the
> exhaust pipe, his words were "the cat converter guts have colapsed and
> all that **** hit the mufler"
> that's why i hear this low frequency mufler noise at about 1.5KRPM.
>
> Now this brings another question to my mind.
> Can i stick any cat converter and mufler in there, the bigger the
> better right? I can weld the pipes with my dad, so i'm thinking i go to
> junker and get my hands dirty.
>
> Do you guys know if anything other than the pipe diameter and the shape
> of the exhaust/cat matters(so as long as it fits and was made for a
> large engine like mine V6 it should be ok, right?)?
>
> thanks
> Ilia