I am thinking of doing the pipe plugs in my LIM on my 2000 Lesabre...I have read that you re-use the UIM gasket and use 1/4 npt recessed pipe plugs...my question * I live in upstate NY and it does get cold here in the winter...yesterday -14 in the morning...

Interested in hearing from ANYONE who has done this mod and if they have ANY issues...

Also is THS the best forum to ask tis question on ???

Thank you

i live in ny too and it has not been a issue, the wife drives the bonnie every day

[QUOTE=jwfirebird;1593555]i live in ny too and it has not been a issue, the wife drives the bonnie every day[/QUO

Can you email me ? I have a couple questons re; the job...

cvcman@twcny.rr.com

how about you pm me, or just put here chances are if you have questions so does someone else who might be reading this down the line

It may be useful to have this posts moved to the "General" discussion area since the job has been / can be done any of the various models with the 3800-II.

ok...here goes..
1) did you reuse the old intake or replace it when you did the plugs ?

2) did you reuse the old UIM gasket or buy new..?

3) did you use 1/4-18 npt brass plugs that are the recessed style that you use an allen wrench on ?

4) did you use pipe dope onthe threads ?

5) did you fill or plug the holes in the plastic UIM or just in the LIM ?

6) did you use a lower temp tstat or the standard ?

Thank you !

I did it on my parents 02 Lesabre. I used the brass plugs with the raised square drive heads. I used pipe tape on the threads and had to grinde about a 1/8 of an inch off tops of the fittings because they were too tall and hit the UIM. I peplaced all the gaskets including the UIM and throttle body. I left the original thermostat in there and haven't had a problem yet.

Even though I did it to my L67, I'll answer your questions using good engineering practices.
1.
2.
3. Recessed allen plugs would be better in this type of application. Just so you don't have to worry about the plenum fitting over the plugs.
4. I wouldn't use tape. Pieces would fall off into the coolant and clog a rad line. Use Black RTV instead.
5. Just plug the holes in the LIM. The upper plenum needs no other work done to it.
6. Standard (195) in winter is fine. I always recommend a 180 in summer time.

the upper intake failure and lower gasket failure are very common on all the plastic intake 3800'* and should be done at once to save aggravation, because they WILL fail at some point, not if. my lower intake gasket was the worst problem of all and it wasent leaking externally, or misfiring or anything (this time) the first time this car had everything done was around 50-60k about 8or 9 yrs ago. that time it had a misfire on cyl 6. its much easier to do it on the bench and i would rather not chance having metal shavings floating around in my coolant ports

1 my upper manifold was visibly leaking, the plastic ones do that. thus the dorman kit 615-180. it has thicker plastic in the areas the gm one fails. the kit comes with new gaskets, egr update, fuel injector gaskets etc.

2 its better to get the dorman kit money wise and hassle wise, so you know everything is new

3 couldnt find the allen ones local, went to home depot lowes, and two plumbing stores, like 75 says you have to grind the square down a little is all.

4 used permatex ultra black because its rated for the fluids the plug will see, the plumbing stuff is for your house.

5 no need to fill anything on the upper

6 no need for anything other than stock temp thermostat unless you plan on having the pcm tuned to adjust fueling and timing tables for the different temp.

pics and info posted here.
https://www.gmforum.com/mechanical-1...2005-a-304071/

well I have the brass recessed 1/4-18 npt plugs, I have taps that size, I have black rtv...may as well Get R Done