New and need HELP

[Papa 10]

Hi. My 97 Bonneville SE I need to have replace gaskets on Upper and Lower Intakes. Also going to do the Head gaskets. I know what the head bolts have to be replaced. Does anyone know if the Lower Intake bolts need to be replaced also and where I can find them?

[BonnieBoy08]

Head gasket replacement is not necessary, failure of those is almost unheard of in the 3800 engines. The bolts shouldn't need replacing. Not a bad idea to do valve cover gaskets, plugs, wires, while you have easy access to everything when its all apart. Metal coolant elbows are also a good thing to do at this point. I went thru this a few months back and here are a few helpful hints from a thread I started. YouTube also has some good videos demonstrating this repair. Hope this helps, good luck on the repair.
http://www.pontiacbonnevilleclub.com/fo ... 39581.html Mine has a supercharger so things will vary slightly but this will give you the jist. If you use the search tool you will be able to find other threads with info. Let us know if you have any further questions. Oh yea...and welcome to the forum!

[J Wikoff]

Yeah, I'd only do the headgaskets if you have signs of failure. Problems with them are rare enough that replacing them as preventative maintenence isn't needed.

[Papa 10]

Thanks for the info. I don't want to fix what isn't broken. What are the signs of head gasket failure?

[J Wikoff]

They are pretty similar to a LIM gasket or upper manifold failure, overheating from lack of coolant, burning coolant, and coolant in the oil, which is what leads to a lot of the confusion. But additionally, there could be exhaust bubbling in the coolant reservoir and loss of compression.

[nos4blood70]

Welcome!

For what it's worth, 3800s basically never have head gasket failures.

[toastedoats]

Welsome!

What I would do:
Swap to Dorman upper intake
Replace lower intake gaskets
Swap to metal coolant elbows

there is basically zero chance you need to do the head gaskets

[WhiteArrow3800]

Welcome aboard. I'd say the same as previously mentioned. Head Gasket failure is highly unlikely the case with these motors. I bought an SSEi from a guy that said the head gaskets were blown and he went as far as getting the top end gasket kits and everything needed but just parked the car. I picked it up, the problem was a $14 water pump and the LIM gaskets.

[Papa 10]

Thanks a lot for all your help. I took apart upper intake and found that the PVC tube was broken off. The gasket and the EGR port was fine but will replace anyway. Both lower intake gaskets were blown through in many spots. I will be putting everything back together today Feb 17. I'll post results later.

[Papa 10]

I replaced UIG and LIG. All good to go now.

[gonzo4191]

Great to hear