Unusual 3.8L Intake Manifold Leak?

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1996 Buick Regal, 83K miles, 3.8L NA engine. Thought I may have
had the characteristic problem with the EGR tube warping the Upper
Intake Manifold. But the leak instead APPEARS (see pix links) to be
originating from the front, not the rear, of the engine, possibly where
a right-angled black plastc coolant tube from the "alternator/serpentine
belt tensioner mount/heater core hose outlet" assembly enters (picture
1) the Lower Intake Manifold. Coolant pools atop the LIM (picture2),
catches on the lip of its parting surface with the engine block (picture
3) and spills down onto the water pump housing and eventually to the
ground. Is this an unusal location for such a leak?

http://members.cox.net/snuckfoe/images/Buick/1.jpg
http://members.cox.net/snuckfoe/images/Buick/2.jpg
http://members.cox.net/snuckfoe/images/Buick/3.jpg
http://members.cox.net/snuckfoe/images/Buick/4.jpg

Some Background.
The car sees limited and infrequent use, probably less than 2K miles/year
and usually no more than once a week. In the summer of 2007 the entire
cooling system was drained, repeatedly flushed with clear water and
refilled with a 55% concentration of Prestone Extended Life Dex-Cool
sans 'Bar's Leaks' or any other additive whatsoever. The leak, which was
initially thought/hoped to be from the water pump shaft seal due to the
location of the evidence on the ground, developed rather suddenly on a
cold morning last month and has grown progressively worse to a current
rate of about a one quart loss in 5 miles of driving.

Any assistance, suggestions, recommedations or thoughts you may have
or provide are cordially encouraged and most welcomed ;^)

SF



Re: Unusual 3.8L Intake Manifold Leak?


I had the plenum failure in a series II 3800 and there was no external leak.
Cylinders filled with water, hydrolocked, etc.

Yours doesnt sound at all like what I experienced.

Now, I have torn down those engines and have to say that the gaskets
can also look pretty darn bad.

Double check and find the location of your leak before you go too much
further.





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Re: Unusual 3.8L Intake Manifold Leak?


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My thinking exactly, and glad I didn't proceed with the notion, as
originally planned, to just start pulling everything preventing the removal
of the UIM. Turns out to very nearly definitively be that pictured "right-
angled black plastic" Coolant Bypass Elbow/Tube, and apparently not
all that uncommon a failure either. Looks like a relatively easy job,
though I'm having an issue with removing the "alternator/serpentine belt
tensioner mount/heater core hose outlet" assembly. The heater hoses
and all three bolts fastening it to the engine are out, it's loose and
wobbles, but just won't fully detach for some still unknown reason. If
anyone has any hints or ideas, I'm all ears ;^)

http://members.cox.net/snuckfoe/images/Buick/Bypass%20Elbow.jpg

My sincere thanx for your gracious response, info.and feedback HLS.

SF


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Re: Unusual 3.8L Intake Manifold Leak?


wrote:

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My kid recently replaced that on his '95 Bonneville (maybe Grand Prix)
with the 3800..
He's due to come over for dinner soon.
I'll ask him, but it might be a different set up.

--Vic
  

Re: Unusual 3.8L Intake Manifold Leak?


On Sat, 11 Apr 2009 19:06:48 -0500, Vic Smith

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He won't change it until it warms up.  It lost about a quart over the
winter.
He's had them off before.  Says the el (your pic) is all that is
holding it.  Pull it straight back.  Only the el o-ring is holding it
in.  This is the VIN K series II engine.
BTW, you can pick up those els at local (Murrays) parts store around
here.  

--Vic

Re: Unusual 3.8L Intake Manifold Leak?


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Yes, this is the VIN K, Series II engine.

The results of my online research would seem to indicate
that there are 2 right-angle elbows, one from the "tensioner"
to the LIM, another from the same to the front cover, used
on this application. However, and although I've still yet to
fully remove the item, it appears that the latter described tube
is in fact a straight shot from the unit into the cover, and likely
the culprit in preventing extraction (the other el simply loosely
dangles).

Thanx to all, who so kindly responded, for their time, advice
and efforts.



Re: Unusual 3.8L Intake Manifold Leak?


My 1995 Old 88 with a 3.8L developed a coolant leak with the belt tensioner
a few years back so your '96 may be leaking in the same place.  Symptoms
were coolant drop in the reservoir, and coolant dripping on the garage floor
from the left side of the engine, viewed from the front of the car.

For what it's worth, my Olds is coming up on 99K miles and is still running
with the original intake manifold, but it's had green coolant for all of
it's miles.

Hope this helps.

Bob




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Re: Unusual 3.8L Intake Manifold Leak?


@newsfe07.iad:

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where
"alternator/serpentine
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(picture
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(picture2),
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(picture
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the
I have same exact car which had the same problem. The belt tensioner
is water cooled & the plastic elbow pipe between the coolant & the
Intake manifold was cracked & leaking coolant.  The whole tensioner
assembly has to be replaced.


Re: Unusual 3.8L Intake Manifold Leak?




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Yes, we also had to do that.   The tensioner flew to pieces which we were
"on the road",
and when that happens, power steering, alternator, brakes, etc stop working.

You would think that you could buy the tensioner without the integrated
plumbing, but that is apparently not the case.

Luckily we cratered near a dealership that had one, and the repair was a
couple hundred bucks.
or so.


Re: Unusual 3.8L Intake Manifold Leak?


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I offer a followup should anyone care or be at all interested.

Still being unable to remove the multi-function belt tensioner
assembly, being careful not to damage the somewhat delicate,
thin walled, cast aluminum device itself or anything else in its
cramped-quarters surroundings, I had begun to consider other
possible and dreaded scenarios that I may have had to resort
to to affect repairs. Among them were pulling and replacing,
as a unit, not only the tensioner assembly (~$100 locally), but
also the multi-function water pump housing/front timing chain
cover assembly (no doubt multiple hundreds of dollars) the
latter of which would require a type (that I don't possess) of
harmonic balancer tool for both removal and re-installation
of the latter.

No matter what I had tried I just COULD NOT remove the
tensioner from the front cover. But lo and behold on Sunday
morning, things progressed from sucks ass to success after
providing a straighter pull by jerking on a strap wrapped
around the heater core oulet passage (that runs through the
tensioner) just before it takes a right angle turn and enters
the front cover (see pic). Then, finally, voila, seperation!
http://members.cox.net/snuckfoe/images/Buick/Tensioner.jpg

Everything appears to be rendered totally serviceable with
only one large and two small O-rings, and one plastic elbow
in need of replacement for a total repair cost of less than $5.
All I now need do is to perform the standard characteristic
procedure of digging out remnants of  the old plastic tube
stuck in both the manifold and tensioner, then reassemble
everything, probably this coming weekend. But I'm fully
expecting all that to proceed acceptably. Overall, I am
for the time being satisfied and somewhat relieved.

Again, my thanx for your all your responses and info guys.