PontiacBonnevilleClub.com

I have a '95 SE Bonneville with the 3800 series II engine. I just finished the LIM and UIM replacement and plan to do the valve cover gaskets tomorrow front and rear. Anyways here are my questions, in no order, just random *shoot* I cant seem to find a straight answer to after searching :(

1. The car makes a rattle from the exhaust upon shifting into reverse or drive from park. Is this common? I've read it can be the heat shield. I know its coming from the exhaust because I had my dad shift the car while I looked underneath and sure engough there was no mistaking its coming from the exhaust pipe. Thoughts on how to fix? Is this a common problem?

2. I just had my mechanic replace 4 mounts. 2 engine, 1 transmission, and 1 somewhere else. How many mounts are there for the engine and transmission? NAPA auto parts only had these 4 mounts to sell me but im thinking is there more?

3. I put an aftermarket oil pan on (it looked high quality and was only $50), however it is leaking from the drain plug. It has a metal bushing. Its snug as hell but oil still drips out. Ideas how to rig something up to fix this? Bolt is not same size as OEM unfortunately... Yea I know..dont buy aftermarket...too late! lol

4. Car seems to be leaking in the rear passenger floor area. No coolant smell and mechanic said its not an issue with the car as far as fluids leaking, it is coming from outside in from the elements. Is there a common seal issue in this area? Any idea how to diagnose this?

5. At night the car wont turn the lights on automatically anymore. I know its something to do with the twilight sentinel sensor, however, I cannot find one of these anywhere! Also, is this related to the dome shaped sensor? or the flat sensor both near the windshield?

6. Car has a issue with reading the temperature outside on the Electronic Climate Control unit. How to fix?

7. When putting the LIM back in after I did the gaskets, I did not follow the torque specs on the twelve bolts, in fact, I didnt even use a torque wrench. I just went around all twelve bolts and tightened them in a staggering random order to just snug, then did a second pass with my hand wrench and tightened them to what I thought was "enough". Is this ok? Car runs amazing after and no signs or coolant leaking anymore. Worth taking it all apart again to get the bolts to the recommended 11ft/lbs? I did try and make sure I tightened every bolt about the same.

8. Lastly, I hope lol, what is a simple and easy way to add a few HP to these cars? Once Im done rebuilding/fixing everything on this car and getting it back to running solid, I wanted to do something simple to add some power or even just help the sound of this amazing engine. I own this car because of this motor I love the 3800 series cars. Please dont say put a L67 in there...Im taking about a cat replacement or a air intake or exhaust swap something simple

Thanks for taking the time to read, I hope to fix all of these issues one by one and then start working on the cosmetic stuff next! New tint, new carpet inside, new headliner/sunshades etc!

1. If the catalytic converter has failed, it will rattle when knocked with a rubber mallet. I don't have more details beyond that.
2. I am a series 1 guy, and I am pretty sure we only have 3, so I will have to take a pass on this
3. They make plastic washers that do this, unless the threads are completely stripped out. If you go in for oil changes, let them know when it goes in, and they should be able to stick a washer in there.
4. If you have a sunroof, check to make sure the drains have not disconnected (in the A and C pillars). If you live in an area with rust issues, check by the rear strut towers in the fender well. Also check to make sure the windshield doesn't leak, as well as door seals. Also check the trunk. It seems like the rear floorboards are the low point of the car and are usually the first to fill. Get this one figured out as quick as possible because the Airbag Control Module is under the passenger seat.
5. It could either be the switch, or the sensor (flat in the defroster vent). The dome is a solar gain sensor for the climate control if memory serves.
6. Check wiring and the basics. Outside temp sensor is in front of the radiator, behind the front grille/bumper. It just looks like a little probe sticking out there with wires running to it.
7. My LIM also got the 'oomph' tight treatment, only because factory torque specs didn't seal everything. If improperly torqued, it could warp the manifold or cause premature gasket failure. I would likely just keep tabs on oil condition, and be ready to do the job again if you find a nice milkshake in your crankcase.
8. Most mods have very low yields on the NA application. Rockers, cam, intake, high flow catalytic converter, and port/polish all help to give it the extra kick, but even so, even the most modified NA3800 could outrun a stock L67.

1. Could be a heat shield or the small bars at the rear bends. #5 in this pic

2. There is one engine mount: torque axis mount on the passenger side.
And three transmission mounts: dogbone under the car on passenger side, front near starter, rear driver's side next to the steering rack.
4. Everything mentioned above plus check the bottoms corners of the rear glass. You can pin point it with a garden hose.

For the exhaust rattle, also check the middle hanger just after
the catalytic converter. There is a screw that rusts out and
breaks, especially if you have had motor mount issues. With
that screw broken, the exhaust will rattle against the hanger.

Headlight switch fails on these cars. It's a problem. You
will lose your dash lights at some point, start looking for
a replacement.

skregal wrote:For the exhaust rattle, also check the middle hanger just after
the catalytic converter. There is a screw that rusts out and
breaks, especially if you have had motor mount issues. With
that screw broken, the exhaust will rattle against the hanger.

Headlight switch fails on these cars. It's a problem. You
will lose your dash lights at some point, start looking for
a replacement.

The switch is bad or the sensors? Because the switch works fine to turn the headlights on and off and manually dim the dash lights etc so what I suspected was the sensors just went bad