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Dodge Caravan 93 3.0l Engine whistles at idle



 
 
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  #1  
Old February 26th 05, 09:42 PM
Paul Singh
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Posts: n/a
Default Dodge Caravan 93 3.0l Engine whistles at idle

When the engine is cold it is OK but at normal temperature if I let the
engine idle it starts giving a loud whistle. If I rev it high it goes away.
The idle RPM is between 750-800. I am pretty sure it does not come from the
belts or pulleys. Any ideas what could be the problem ?

TIA
Paul


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  #2  
Old February 26th 05, 11:45 PM
maxpower
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Default

Could be a vacuum leak, listen under the hood at idle.

Glenn Beasley
Chrysler Tech
"Paul Singh" > wrote in message
news:4b5Ud.48922$uc.30511@trnddc03...
> When the engine is cold it is OK but at normal temperature if I let the
> engine idle it starts giving a loud whistle. If I rev it high it goes

away.
> The idle RPM is between 750-800. I am pretty sure it does not come from

the
> belts or pulleys. Any ideas what could be the problem ?
>
> TIA
> Paul
>
>



  #3  
Old February 27th 05, 01:21 AM
Paul Singh
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Posts: n/a
Default

Thanks for the reply.
While the engine is running I have tried to unplug and plug the vacuum pipes
back. The darn thing does not seem to make any difference. I just can;t seem
to locate the source. I will keep trying.

-Paul

"maxpower" > wrote in message
...
> Could be a vacuum leak, listen under the hood at idle.
>
> Glenn Beasley
> Chrysler Tech
> "Paul Singh" > wrote in message
> news:4b5Ud.48922$uc.30511@trnddc03...
>> When the engine is cold it is OK but at normal temperature if I let the
>> engine idle it starts giving a loud whistle. If I rev it high it goes

> away.
>> The idle RPM is between 750-800. I am pretty sure it does not come from

> the
>> belts or pulleys. Any ideas what could be the problem ?
>>
>> TIA
>> Paul
>>
>>

>
>



  #4  
Old February 27th 05, 01:58 AM
Steve
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Posts: n/a
Default

Check the PCV valve by temporarily removing/bypassing it. Some
aftermarket valves will whistle like a train.

  #5  
Old February 27th 05, 12:22 PM
maxpower
external usenet poster
 
Posts: n/a
Default


"Paul Singh" > wrote in message
news:Eo8Ud.31500$uc.27265@trnddc01...
> Thanks for the reply.
> While the engine is running I have tried to unplug and plug the vacuum

pipes
> back. The darn thing does not seem to make any difference. I just can;t

seem
> to locate the source. I will keep trying.
>
> -Paul
>
> "maxpower" > wrote in message
> ...
> > Could be a vacuum leak, listen under the hood at idle.
> >
> > Glenn Beasley
> > Chrysler Tech
> > "Paul Singh" > wrote in message
> > news:4b5Ud.48922$uc.30511@trnddc03...
> >> When the engine is cold it is OK but at normal temperature if I let the
> >> engine idle it starts giving a loud whistle. If I rev it high it goes

> > away.
> >> The idle RPM is between 750-800. I am pretty sure it does not come from

> > the
> >> belts or pulleys. Any ideas what could be the problem ?
> >>
> >> TIA
> >> Paul
> >>
> >>

> >
> >

it could be a broken intake gasket, if it is a vacuum leak, take a runner
hose to your ear and use it as a stethoscope to locate the leak, or at lease
eliminate that possibility
>



  #6  
Old February 28th 05, 07:46 AM
Paul Singh
external usenet poster
 
Posts: n/a
Default


"maxpower" > wrote in message
...
> it could be a broken intake gasket, if it is a vacuum leak, take a runner
> hose to your ear and use it as a stethoscope to locate the leak, or at
> lease
> eliminate that possibility
>>

>
>

In between I have cleaned the throttle body, air plennum and fuel
injectors( new O rings). All the gaskets were
replaced with the new and the bolts were tightened to the FRM specified
torques. Lot of black stuff I removed. The whistle was there before and
still is. I cleaned the intake area because I have never cleaned it in over
12 years. So I suspect that is not the cause. Last night I looked at it
again but nothing positive to report about. I think it may help if I explain
the symptoms a little more.

a) The whistle only comes when the Engine is at operating temps.
b) If I come home and sit there for couple of minutes without turning the
engine off, no whistle.
c) If I let it idle for few more minutes, whistle yes. If I rev it, it goes
away. Let it idle, it will come back.
d) Driving normally, no whistle.
e) While idling if the radiator fan comes on, whistle goes away. It comes
back as soon as the fan stops.
f) I removed the PCV valve suction pipe and put my finger on the PCV valve
to seal the suction. Nope it didn;t help. I can remove the PCV valve
completely and then see if the whistle goes away.

Lately I also replaced the thermostat because of the engine code. The
thermostat I bought is not made by chrysler but got it from Schucks which I
think is made by prestone. Come to think of it, the whistle was there prior
to replacing the thermostat.

I tried to locate the vacuum leak. No luck yet. While the engine is running
I tried removing one vacuum pipe at a time to see if that makes any
difference. No luck. Well, I haven't tried all of them yet.

The fan belts seem to have proper tension, auto tensioner is free to move
and has good tension to keep the belt tight. The compressor belt has enough
tension. I have tried different levels of tension on the compressor belt. I
would suspect the pulleys if the whistle is there all the time. If I start
the engine cold, no whistle. It starts suddenly when the temp is about to
reach the operating level.

Can it be ignition timing related at all ?

Bloody hell, I can't even pin point where the whistle is coming from. I
asked my wife to help me locate the area it may be coming from. She seems to
think it is from the left side of the engine i.e. the surpentine belt area.
It is getting to be a challenge now.

I will try your runner hose method and will report.

-Paul



  #7  
Old February 28th 05, 10:30 AM
maxpower
external usenet poster
 
Posts: n/a
Default


"Paul Singh" > wrote in message
news:u7zUd.43418$EL5.35643@trnddc05...
>
> "maxpower" > wrote in message
> ...
> > it could be a broken intake gasket, if it is a vacuum leak, take a

runner
> > hose to your ear and use it as a stethoscope to locate the leak, or at
> > lease
> > eliminate that possibility
> >>

> >
> >

> In between I have cleaned the throttle body, air plennum and fuel
> injectors( new O rings). All the gaskets were
> replaced with the new and the bolts were tightened to the FRM specified
> torques. Lot of black stuff I removed. The whistle was there before and
> still is. I cleaned the intake area because I have never cleaned it in

over
> 12 years. So I suspect that is not the cause. Last night I looked at it
> again but nothing positive to report about. I think it may help if I

explain
> the symptoms a little more.
>
> a) The whistle only comes when the Engine is at operating temps.
> b) If I come home and sit there for couple of minutes without turning the
> engine off, no whistle.
> c) If I let it idle for few more minutes, whistle yes. If I rev it, it

goes
> away. Let it idle, it will come back.
> d) Driving normally, no whistle.
> e) While idling if the radiator fan comes on, whistle goes away. It comes
> back as soon as the fan stops.
> f) I removed the PCV valve suction pipe and put my finger on the PCV valve
> to seal the suction. Nope it didn;t help. I can remove the PCV valve
> completely and then see if the whistle goes away.
>
> Lately I also replaced the thermostat because of the engine code. The
> thermostat I bought is not made by chrysler but got it from Schucks which

I
> think is made by prestone. Come to think of it, the whistle was there

prior
> to replacing the thermostat.
>
> I tried to locate the vacuum leak. No luck yet. While the engine is

running
> I tried removing one vacuum pipe at a time to see if that makes any
> difference. No luck. Well, I haven't tried all of them yet.
>
> The fan belts seem to have proper tension, auto tensioner is free to move
> and has good tension to keep the belt tight. The compressor belt has

enough
> tension. I have tried different levels of tension on the compressor belt.

I
> would suspect the pulleys if the whistle is there all the time. If I start
> the engine cold, no whistle. It starts suddenly when the temp is about to
> reach the operating level.
>
> Can it be ignition timing related at all ?
>
> Bloody hell, I can't even pin point where the whistle is coming from. I
> asked my wife to help me locate the area it may be coming from. She seems

to
> think it is from the left side of the engine i.e. the surpentine belt

area.
> It is getting to be a challenge now.
>
> I will try your runner hose method and will report.
>
> -Paul
>
>

Sounds like it changes when the load changes (vacuum) I would suspect a
piece of old gasket left when reassembled. but without hearing it, it is
hard to tell. get out that heater hose and use it as a stethoscope and you
will pin point the noise


  #8  
Old February 28th 05, 12:13 PM
Bill Putney
external usenet poster
 
Posts: n/a
Default

Paul Singh wrote:

> "maxpower" > wrote in message
> ...
>
>>it could be a broken intake gasket, if it is a vacuum leak, take a runner
>>hose to your ear and use it as a stethoscope to locate the leak, or at
>>lease
>>eliminate that possibility
>>
>>

> In between I have cleaned the throttle body, air plennum and fuel
> injectors( new O rings). All the gaskets were
> replaced with the new and the bolts were tightened to the FRM specified
> torques. Lot of black stuff I removed. The whistle was there before and
> still is. I cleaned the intake area because I have never cleaned it in over
> 12 years. So I suspect that is not the cause. Last night I looked at it
> again but nothing positive to report about. I think it may help if I explain
> the symptoms a little more.
>
> a) The whistle only comes when the Engine is at operating temps.
> b) If I come home and sit there for couple of minutes without turning the
> engine off, no whistle.
> c) If I let it idle for few more minutes, whistle yes. If I rev it, it goes
> away. Let it idle, it will come back.
> d) Driving normally, no whistle.
> e) While idling if the radiator fan comes on, whistle goes away. It comes
> back as soon as the fan stops.
> f) I removed the PCV valve suction pipe and put my finger on the PCV valve
> to seal the suction. Nope it didn;t help. I can remove the PCV valve
> completely and then see if the whistle goes away.
>
> Lately I also replaced the thermostat because of the engine code. The
> thermostat I bought is not made by chrysler but got it from Schucks which I
> think is made by prestone. Come to think of it, the whistle was there prior
> to replacing the thermostat.
>
> I tried to locate the vacuum leak. No luck yet. While the engine is running
> I tried removing one vacuum pipe at a time to see if that makes any
> difference. No luck. Well, I haven't tried all of them yet.
>
> The fan belts seem to have proper tension, auto tensioner is free to move
> and has good tension to keep the belt tight. The compressor belt has enough
> tension. I have tried different levels of tension on the compressor belt. I
> would suspect the pulleys if the whistle is there all the time. If I start
> the engine cold, no whistle. It starts suddenly when the temp is about to
> reach the operating level.
>
> Can it be ignition timing related at all ?
>
> Bloody hell, I can't even pin point where the whistle is coming from. I
> asked my wife to help me locate the area it may be coming from. She seems to
> think it is from the left side of the engine i.e. the surpentine belt area.
> It is getting to be a challenge now.
>
> I will try your runner hose method and will report.
>
> -Paul


The noise coming on just as it reaches operating temp, and the fans
being on or not affecting it - what shape is the coolant pressure cap in
(i.e., does it need replacing?)? Also, the fans coming on could simply
be changing engine operation enough to cause the noise to stop by
loading the alternator.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')
  #9  
Old February 28th 05, 02:29 PM
Jack Idler
external usenet poster
 
Posts: n/a
Default


"Bill Putney" > wrote in message
...
> Paul Singh wrote:
> <severly clipped>
> >
> > Bloody hell, I can't even pin point where the whistle is coming from. I
> > asked my wife to help me locate the area it may be coming from. She

seems to
> > think it is from the left side of the engine i.e. the surpentine belt

area.
> > It is getting to be a challenge now.
> >
> > I will try your runner hose method and will report.
> >
> > -Paul

>
> The noise coming on just as it reaches operating temp, and the fans
> being on or not affecting it - what shape is the coolant pressure cap in
> (i.e., does it need replacing?)? Also, the fans coming on could simply
> be changing engine operation enough to cause the noise to stop by
> loading the alternator.
>
> Bill Putney
> (To reply by e-mail, replace the last letter of the alphabet in my
> adddress with the letter 'x')


Some FEAD tensioners use a damping shoe arrangment to tame wierd belt
dynamics at idle or with varying loads . I have an older minivan (with most
likely
a worn out damper) that will get into belt squeal at the alternator at idle,
but the
squeal goes away with any amount of increased throttle.....just a small shot
of
spray-on belt dressing will quiet it for days at a time.


  #10  
Old February 28th 05, 07:40 PM
maxpower
external usenet poster
 
Posts: n/a
Default


"Jack Idler" > wrote in message
...
>
> "Bill Putney" > wrote in message
> ...
> > Paul Singh wrote:
> > <severly clipped>
> > >
> > > Bloody hell, I can't even pin point where the whistle is coming from.

I
> > > asked my wife to help me locate the area it may be coming from. She

> seems to
> > > think it is from the left side of the engine i.e. the surpentine belt

> area.
> > > It is getting to be a challenge now.
> > >
> > > I will try your runner hose method and will report.
> > >
> > > -Paul

> >
> > The noise coming on just as it reaches operating temp, and the fans
> > being on or not affecting it - what shape is the coolant pressure cap in
> > (i.e., does it need replacing?)? Also, the fans coming on could simply
> > be changing engine operation enough to cause the noise to stop by
> > loading the alternator.
> >
> > Bill Putney
> > (To reply by e-mail, replace the last letter of the alphabet in my
> > adddress with the letter 'x')

>
> Some FEAD tensioners use a damping shoe arrangment to tame wierd belt
> dynamics at idle or with varying loads . I have an older minivan (with

most
> likely
> a worn out damper) that will get into belt squeal at the alternator at

idle,
> but the
> squeal goes away with any amount of increased throttle.....just a small

shot
> of
> spray-on belt dressing will quiet it for days at a time.
>

Be careful with that belt dressing, allot of times the belt squeals because
of alignment problems, and putting that stuff on my make the belt slide off
the tensioner, Not saying that is why yours is squealing


 




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