Intake Manifold leak

rob teed

New member
Jun 1, 1999
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OK guys..let me tell ya what I'm up to.
I took the intake manifold off last year when I redid
the heads.I had pulled the carb off and removed a small
plate next to the carb..some kind of heat riser. I had
the intake baked to clean it up then painted it.
I'll tell ya..It gets HOT! The paint in the center
crossovers section burned right off,anyway I guess the
intake was pitted around that heat riser plate..on
our way to Florida last year it started leaking.
Flames shot from the plate to the valve covers burned
the wiring harness and the vacumn lines. I made a new
gasket and put the plate back on. Well this last trip
to Gilberts it was sounding quite loud so I took it
back off. You can see carbon on the manifold on
both sides of the plate..right up to the carb.Im
getting rid of the heat riser. A machine shop is
making a 1/4" steel plate to cover the hole and I have
some new gasket material to use with it.
I think I'm real lucky not to have had a fire...but I
had covered the area around the plate with aluminum
foil after the wires were burned.
Anyone else ever have this problem? I hope I discribed
it good enough to make sense.
Oh..btw..If you ever take your intake manifold off plug
the crossovers up....that may be what I need to do. As
it is sometimes when it get running hot seems to boil
the gas out of the carb..thats what I think anyway.
Rob Teed 74 Painted Desert
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Hi Tom,
Does mondellos have an online catalog?
Rob
> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of tom warner
> Sent: Thursday, June 15, 2000 10:44 PM
> To: gmcmotorhome
> Subject: Re:GMC: Intake Manifold leak
>
>
> The single biggest fault of these heads and manifolds. Get mondellos
> stainless steel caps and plugs if you do not want to take off the heads.
>

> >OK guys..let me tell ya what I'm up to.
> >I took the intake manifold off last year when I redid
> >the heads.I had pulled the carb off and removed a small
> >plate next to the carb..some kind of heat riser. I had
> >the intake baked to clean it up then painted it.
> >I'll tell ya..It gets HOT! The paint in the center
> >crossovers section burned right off,anyway I guess the
> >intake was pitted around that heat riser plate..on
> >our way to Florida last year it started leaking.
> >Flames shot from the plate to the valve covers burned
> >the wiring harness and the vacumn lines. I made a new
> >gasket and put the plate back on. Well this last trip
> >to Gilberts it was sounding quite loud so I took it
> >back off. You can see carbon on the manifold on
> >both sides of the plate..right up to the carb.Im
> >getting rid of the heat riser. A machine shop is
> >making a 1/4" steel plate to cover the hole and I have
> >some new gasket material to use with it.
> >I think I'm real lucky not to have had a fire...but I
> >had covered the area around the plate with aluminum
> >foil after the wires were burned.
> >Anyone else ever have this problem? I hope I discribed
> >it good enough to make sense.
> >Oh..btw..If you ever take your intake manifold off plug
> >the crossovers up....that may be what I need to do. As
> >it is sometimes when it get running hot seems to boil
> >the gas out of the carb..thats what I think anyway.
> >Rob Teed 74 Painted Desert
> >_____________________________________________
> >NetZero - Defenders of the Free World
> >Click here for FREE Internet Access and Email
> >http://www.netzero.net/download/index.html
> >
> >
>
>
_____________________________________________
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Thanks Tom,
I'm going to check it out.
Rob

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of tom warner
> Sent: Thursday, June 15, 2000 10:54 PM
> To: gmcmotorhome
> Subject: RE: GMC: Intake Manifold leak
>
>
> http://www.mondellotwister.com/
>
>

> >Hi Tom,
> >Does mondellos have an online catalog?
> >Rob
> >> -----Original Message-----
> >> From: owner-gmcmotorhome
> >> [mailto:owner-gmcmotorhome]On Behalf Of tom warner
> >> Sent: Thursday, June 15, 2000 10:44 PM
> >> To: gmcmotorhome
> >> Subject: Re:GMC: Intake Manifold leak
> >>
> >>
> >> The single biggest fault of these heads and manifolds. Get mondellos
> >> stainless steel caps and plugs if you do not want to take off
> the heads.
> >>

> >> >OK guys..let me tell ya what I'm up to.
> >> >I took the intake manifold off last year when I redid
> >> >the heads.I had pulled the carb off and removed a small
> >> >plate next to the carb..some kind of heat riser. I had
> >> >the intake baked to clean it up then painted it.
> >> >I'll tell ya..It gets HOT! The paint in the center
> >> >crossovers section burned right off,anyway I guess the
> >> >intake was pitted around that heat riser plate..on
> >> >our way to Florida last year it started leaking.
> >> >Flames shot from the plate to the valve covers burned
> >> >the wiring harness and the vacumn lines. I made a new
> >> >gasket and put the plate back on. Well this last trip
> >> >to Gilberts it was sounding quite loud so I took it
> >> >back off. You can see carbon on the manifold on
> >> >both sides of the plate..right up to the carb.Im
> >> >getting rid of the heat riser. A machine shop is
> >> >making a 1/4" steel plate to cover the hole and I have
> >> >some new gasket material to use with it.
> >> >I think I'm real lucky not to have had a fire...but I
> >> >had covered the area around the plate with aluminum
> >> >foil after the wires were burned.
> >> >Anyone else ever have this problem? I hope I discribed
> >> >it good enough to make sense.
> >> >Oh..btw..If you ever take your intake manifold off plug
> >> >the crossovers up....that may be what I need to do. As
> >> >it is sometimes when it get running hot seems to boil
> >> >the gas out of the carb..thats what I think anyway.
> >> >Rob Teed 74 Painted Desert
> >> >_____________________________________________
> >> >NetZero - Defenders of the Free World
> >> >Click here for FREE Internet Access and Email
> >> >http://www.netzero.net/download/index.html
> >> >
> >> >
> >>
> >>
> >_____________________________________________
> >NetZero - Defenders of the Free World
> >Click here for FREE Internet Access and Email
> >http://www.netzero.net/download/index.html
> >
> >
>
>
_____________________________________________
NetZero - Defenders of the Free World
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Rob,

I had a similar problem only it was the gasket under the EGR valve on the
left side. It got enough fire it scorched the gasket under the carb. Then
NAPA sold me a low temp gasket and it happened again after a couple of
hundred miles. Finally bought some high temp gasket material to fix it.
Counting the two emergency fixes on the road it took four trys.

Any one else encountering this problem should shut down and fix it
immediately. This is one fix that can't wait.

Dick Kennedy

>OK guys..let me tell ya what I'm up to.
>I took the intake manifold off last year when I redid
>the heads.I had pulled the carb off and removed a small
>plate next to the carb..some kind of heat riser. I had

>Rob Teed 74 Painted Desert
>_____________________________________________
>NetZero - Defenders of the Free World
>Click here for FREE Internet Access and Email
>http://www.netzero.net/download/index.html
>
>
 
Hi Arch,
Real nice meeting ya at Gilberts. That was our first GMC
rally ever..even the wife liked going to it. I'm thinking I should just pull
the intake off and close them up...man I hate to do that!!!!
Rob Teed 74 Painted Desert

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of Gcbr
> Sent: Friday, June 16, 2000 9:54 AM
> To: gmcmotorhome
> Subject: Re: GMC: Intake Manifold leak
>
>
> In a message dated 6/15/00 9:27:17 PM Central Daylight Time,

>
> > Oh..btw..If you ever take your intake manifold off plug
> > the crossovers up....that may be what I need to do. As
> > it is sometimes when it get running hot seems to boil
> > the gas out of the carb..thats what I think anyway.
>
> Rob
>
> I agree with you. I painted my new manifold and the paint is still there.
> The difference in the morning is not that much. It just takes 2 or 3 min
> longer to warm up. The big thing I have noticed is that when I make a
> short stop the engine starts right back up. Rest stops are not a problem.
> The other thing I would add is have the thing Magna Fluxed to check for
> leaks. The people around me say that most of them are probably
> cracked. I dont know----mine was.
>
> Take Care
> Arch
>

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Dick:

My 403 cid engine does not have an EGR valve on the left side of the carburetor.
However, it does have a plate where one would be mounted.

Paul Bartz

From: owner-gmcmotorhome
[mailto:owner-gmcmotorhome]On Behalf Of Dick Kennedy
Sent: Thursday, June 15, 2000 11:42 PM

Rob,

I had a similar problem only it was the gasket under the EGR valve on the
left side. It got enough fire it scorched the gasket under the carb. Then
NAPA sold me a low temp gasket and it happened again after a couple of
hundred miles. Finally bought some high temp gasket material to fix it.
Counting the two emergency fixes on the road it took four trys.

Any one else encountering this problem should shut down and fix it
immediately. This is one fix that can't wait.

Dick Kennedy

>OK guys..let me tell ya what I'm up to.
>I took the intake manifold off last year when I redid
>the heads.I had pulled the carb off and removed a small
>plate next to the carb..some kind of heat riser. I had

>Rob Teed 74 Painted Desert
>_____________________________________________
>NetZero - Defenders of the Free World
>Click here for FREE Internet Access and Email
>http://www.netzero.net/download/index.html
>
>
 
Hi Gene,
I wish I would have known about this when I had the intake off! Thanks for
the pics.
Rob Teed

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of gene
> Sent: Saturday, June 17, 2000 10:39 PM
> To: gmcmotorhome
> Subject: Re:GMC: Intake Manifold leak
>
>
>
>
> You might want to review these pictures of what Mondello did to fix this
> problem for me.
>
http://albums.photopoint.com/j/AlbumIndex?u=128904&a=1619678

>OK guys..let me tell ya what I'm up to.>>>>>

Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

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There is some question in my mind about blocking the intake and not the
heads. The pressures are still on the gasket, but it is doing ok for the
last 3,000 miles or so. Mondello has pushed this for some time so we will
see how it goes. There was an article in HotRod this month showing this
same type of blocking.
gene

>Hi Gene,
> I wish I would have known about this when I had the intake off! Thanks for
>the pics.
>Rob Teed
>
>> -----Original Message-----
>> From: owner-gmcmotorhome
>> [mailto:owner-gmcmotorhome]On Behalf Of gene
>> Sent: Saturday, June 17, 2000 10:39 PM
>> To: gmcmotorhome
>> Subject: Re:GMC: Intake Manifold leak
>>
>>
>>
>>
>> You might want to review these pictures of what Mondello did to fix this
>> problem for me.
>>
>http://albums.photopoint.com/j/AlbumIndex?u=128904&a=1619678
>

>>OK guys..let me tell ya what I'm up to.>>>>>
>
>Genef -- 77PB/ore/ca
>GMC MOTORHOME INFORMATION
>mr.erf
>http://www.california.com/~eagle/
>
>_____________________________________________
>NetZero - Defenders of the Free World
>Click here for FREE Internet Access and Email
>http://www.netzero.net/download/index.html
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/