Unusual 3.8L Intake Manifold Leak?

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

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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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wrote:

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

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

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

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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.

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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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where

"alternator/serpentine

(picture

(picture2),

(picture

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.

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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.

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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.

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