Originally Posted by the3800guy
Goto google and type in "3800 intake repair"
The first thing that will show up is this link
If you can follow those instructions correctly you will have the tightest system you can ever wish for without having to buy a new intake.
Thanks, and welcome to Bonneville Club! Downloaded the folder and reviewed the method. The tubing loop is an ingenious idea, as it will allow for coolant flow from the rear LIM chamber to the thermostat housing, but as the throttle body is now out of the loop, throttle plate heating is sacrificed.
A lot of us here on BC have been busy with this problem too.
Have you read this article? :
There is only one cheap method I am aware of that will do a good job of fixing a failed UIM for less than $20 and retain throttle body heat. It is based on Ken Spragg'* idea of installing a reduced diameter stovepipe and a heat shield to provide an insulating gap and a heat barrier for the plastic upper:
There are other articles here on BC for modifying Dorman uppers, and for adapting and shielding Dorman pipes that were developed before we all became aware of the APN sleeved upper and rd pipe mentioned in the Techinfo article above. All of this stuff is really now only of academic interest, as the APN fix gets it done right the first time for a pretty good price.
I also noticed the coolant fill method referenced in the Geocities guide does not go into much detail, and if done like most fellows do, (filling at the radiator only) can result in air trapped in the engine. Through trial and error, we found a way to minimize trapped air:
Coolant fill method for L-36: