I was wondering if anyone could help me out with find a good place for bonnieville information. I need to find engine parts for a 99, 3.8L, non supercharged Bonneville. It is my parents car and only has about 50,000 miles on it. My little brother was driving it and either cracked the head, blew the head gasket or a comb of both. I told them I would try to fix it, instead of them going to a stealership to save them a lot of money. So anyone with a link, part number or just some general experience would greatly help me out.

thanks - J

P.s Is this a 90 or 60 degree V6?

 

Here's a Bonneville site: http://www.bonnevilleclub.com/forum/

99 used the 3.8L L36 engine (which is 90 degree), same as V6 F-bodies had

Here's instructions on head (and/or gasket) replacement:

1999 Pontiac Bonneville
Cylinder Head Replacement

Tools Required: J 36660-A Torque Angle Meter

Removal Procedure

Caution: Before servicing any electrical component, the ignition key must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.

1. Disconnect the negative battery cable.
2. Remove the intake manifold.
3. Remove the exhaust manifold.
4. Remove the arm cover.
5. Remove the electronic ignition module.
6. Remove the spark plug wires.
7. Remove the generator bracket.
8. Remove the A/C compressor bracket bolt.
9. Remove the power steering pump.
10. Remove the belt tensioner. For VIN 1 engines, remove the supercharger belt tensioner.
11. Remove the fuel pipe heat shield.
12. Remove the valve rocker arm assemblies.
13. Remove the pushrods.
14. Remove the cylinder head bolts. Discard the bolts.
15. Remove the cylinder head.
16. Clean all of the gasket mating surfaces.
17. Inspect the cylinder head.

Installation Procedure

Notice: This engine uses special torque-to-yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage.

Notice: This bolt [the cylinder head bolts] is designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt that is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The system or the components may be damaged.

1. Clean the threads in the block. Use a 7/16-14 tap.
2. Install the head gasket with the arrow pointing to the front of the engine.
3. Install the new cylinder head bolts.
- Tighten the new cylinder head bolts in sequence [see attached image] to 50 N·m (37 lb ft).
- Rotate each bolt 130 degrees in sequence. Use the J 36660-A .
- Rotate the center four bolts an additional 30 degrees. Use the J 36660-A .
4. Install the pushrods.
5. Install the guide plate.
6. Install the valve rocker arm.
7. Install the A/C compressor bracket bolt. Tighten the bolt to 70 N·m (52 lb ft).
8. Install the generator support bracket to the cylinder head.
9. Install the generator (alternator).
10. Install the electronic ignition module.
11. Install the belt tensioner.
12. Install the spark plug wires.
13. Install the power steering pump.
14. Install the fuel pipe heat shield.
15. Connect the negative battery cable.

 

If your loosing water check the plastic intake manifold, I've seen quite a few that are bad, they leak water internally near the TB

 

Thanks for the great help guys. I knew i could count on the people @ ls1tech.com.

 

Just did a 98 bonneville 2 weeks ago that had a bad upper intake. Had a hydrolock problem w/ antifreeze filling up the cylinders and found the hole in the plastic. It was where the egr pipe runs between the two coolant passages behind the throttle body(internally, you can't see it)I made the mistake of leaving the pcv valve out of one about two years ago and it made the most mysterious squeal. If you replace upper manifold don't forget to dig out pcv under the map sensor.

 

Funny I just helped a friend with one last weekend. The upper intake gets a crack in it right around an egr port and that acts like a vaccum and sucks the coolant right in. If you are lucky (and nothing got bent from the hydrolock) then all you need to do is an upper intake plus a gasket and take out all of the plugs turn it over to push out most of the coolant and you should be good to go. May be a good time for plugs, do an oil change. The aftermarket manifolds have a correction to keep it from happening again.

 

my wife has a 98 grand prix with the 3.8 and i had to change a blown head gasket and about a year later I had to replace the upper intake.kept finding anti-freeze in the oil.talked to a GM tech that said head gaskets and upper intakes are very known problems with the 3.8 (3800) V6