Intake issues?
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RexCaron
- LE Member
- Posts: 5
- Joined: Fri Sep 07, 2012 1:48 pm
- Year and Trim: 1994 Pontiac Bonneville se
- Location: Lincoln,IL
Intake issues?
In the last 24 hours ive been told by (mostly) auto parts people that the intake in my 1994 bonneville is going to need changed soon?? Why? I noticed that it is not aluminum but what does this matter? Just curious and this seems like the best place to be curious so if anyone knows or has an opinion lets hear it! Thanks fellas
Re: Intake issues?
The 3.8 is notorious for upper and lower intake leaks my advice is to change lower gaskets on intake and replace plenum and gaskets before it leaks so bad that it hydro locks the motor like mine did,good luck
- J Wikoff
- Administrator

- Posts: 17080
- Joined: Mon May 19, 2008 7:01 pm
- Year and Trim: 1992 SSE
2009 G8 GT - Location: Central Illinois
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Re: Intake issues?
I would be much more concerned if yours was a 95, when they changed to the lower intake gaksets and upper intake design that was prone to issues. 94 and before are not overly prone to failures. Its LIM gaskets can age over time and start to leak, but aren't all that likely to fail and kill the engine like the 95+ would. And in all my years on Bonneville forums, only one person has reported finding any issues with the pre-95 upper intake, and that was just recently in the south west. With the age yours has on it, I'd probably go in and change the LIM gaskets, but I wouldn't be sweating it unless you see that it's losing coolant with no visible external leaks.

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers & a 10" Alpine Type R Sub, all the watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override, Monroe Reflex struts, red calipers
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights
- 3800SERIESII
- Posts like an LG3

- Posts: 308
- Joined: Fri Apr 06, 2012 7:37 pm
- Year and Trim: 1999 Pontiac Bonneville SE
1997 Pontiac Firebird
Re: Intake issues?
They are plastic which spells trouble. Expanding and contracting rapidly is bound to cause a gap and leak antifreeze in the cylinders, I would do it regardless. Just found out today that mine is ORIGINAL! cant believe it. it was manufactured september 26,1995. it is a 1996 model with 250k.
1999 Pontiac Bonneville SE- Stored -All stock, Sony CDX-GT570UP HU w/ Scosche HD 6.5"'s front/Alpine S 6x9 rear, 153,000 miles
1996 Pontiac Bonneville SE- Now a parts car - HAI, Muffler Delete, Summit Y-pipe, 250,000 miles

1997 Pontiac Firebird - DD - 3800 Series II, Cold air intake/FWI, Y87 Package, Sony DSX-S100 Digital Media Reciever, 180,000 miles
1996 Pontiac Bonneville SE- Now a parts car - HAI, Muffler Delete, Summit Y-pipe, 250,000 miles

1997 Pontiac Firebird - DD - 3800 Series II, Cold air intake/FWI, Y87 Package, Sony DSX-S100 Digital Media Reciever, 180,000 miles
- J Wikoff
- Administrator

- Posts: 17080
- Joined: Mon May 19, 2008 7:01 pm
- Year and Trim: 1992 SSE
2009 G8 GT - Location: Central Illinois
- Contact:
Re: Intake issues?
There are probably 30 or more major Series II LIM gasket or UIM failures for every 1 seeping Series I LIM gasket.

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers & a 10" Alpine Type R Sub, all the watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override, Monroe Reflex struts, red calipers
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights
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RexCaron
- LE Member
- Posts: 5
- Joined: Fri Sep 07, 2012 1:48 pm
- Year and Trim: 1994 Pontiac Bonneville se
- Location: Lincoln,IL
Re: Intake issues?
Well all of this was good to know. Thanks to everyone
- RJolly87
- Certified Bonneville Nut

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1994 Buick Regal Custom - Location: Las Cruces, NM
Re: Intake issues?
Just to seal the deal on this thread, I was the one who reported the bad UIM on mine.
The failure:

You will note that on the composite upper, there is a gasket around the intake runners. The coolant will leak out usually long before it goes in to the runners.
Mine leaked a LONG time, and the leak turned catastrophic before I just did a LIM gasket job, and replaced everything down and back.
Upon changing the plugs, the only plug that smelled of anything was #1, and that was oil, I suspect from the PCV.
But in short, most are referencing the Series 2, which ran 95-2005. If you are concerned about it, just keep tabs on your coolant level. If it starts to drop, track down the problem.
The failure:

You will note that on the composite upper, there is a gasket around the intake runners. The coolant will leak out usually long before it goes in to the runners.
Mine leaked a LONG time, and the leak turned catastrophic before I just did a LIM gasket job, and replaced everything down and back.
Upon changing the plugs, the only plug that smelled of anything was #1, and that was oil, I suspect from the PCV.
But in short, most are referencing the Series 2, which ran 95-2005. If you are concerned about it, just keep tabs on your coolant level. If it starts to drop, track down the problem.
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

