Write-Up: Removing Broken Threads - Coolant Fitting

Write up: 95SC - Removing broken threads from the large coolant fitting

On the 1995 Buick Riviera, there is a large threaded coolant fitting on the left side of the Lower Intake Manifold, closest to the front. On a stock 95, this coolant fitting can be made of plastic and will often crack and break off with the threads still in the LIM. When doing a LIM swap on my 95, I found a large crack almost all the way around the fitting. Fortunately I was swapping the LIM anyway and didn't really need to remove the threaded portion. I went through the process required to remove the threads anyway, in case someone had the need to remove the threads due to not having a spare LIM on hand.

Broken fitting sitting on LIM:



There are two methods that the threads can be removed. The first method can be done with the LIM still on the car and possibly with the supercharger still attached. The second method is for if the broken part of the fitting is stubborn, and requires the removal of the LIM.

Below we can see the threaded fitting still in the LIM. Note the coloring, the yellow is where the crack had been for quite some time. The black section is where it finally snapped when I was gently handling the coolant lines. This thing basically fell off in my hand!



Method one:
The first method involves the use of a sharp length of metal, with crisp edges. In the picture below a cutter from a lathe is used to give you the idea. Also an appropriately sized chisel can be used, or very large slot screwdriver. Basically, what you are looking for is something that will fit tightly in the hole with some edge that can catch the plastic. Use a wrench or pliers to turn it counter clockwise. Be careful, as the plastic is quite soft.



Method two:
The second method requires the removal of the LIM. This is for if nothing you can do is getting the threads out. This might also be a great time to port and polish the LIM. Using a very small chisel, gently chip at the broken bit in a direction that encourages it to turn in a counter-clock wise direction. In the event that it still won't turn, you can just gently chip the whole thing out.



Clean up for method two:
Now use a 3 / 4 NPT tap to clean out the threads from gouges or bits of plastic. If you absolutely don't have this tap, I suppose you could skip this step if you were careful in removing the broken bit, or if method one worked fine for you.




I hope this helps for ideas!

Nice write up and great pictures i will def be using this as i try to fix my car. So would you reccomend getting both new threads and the other part that slides into it. thanks for write up this helped cearify alot and will help others who have this problem too.

If your fitting is plastic, for sure get the metal one. The other part which is S shaped should be fine, just will need a new O-ring.

Karma wrote:

If your fitting is plastic, for sure get the metal one. The other part which is S shaped should be fine, just will need a new O-ring.

well i just went to see my mechanic and brung some of your pictures to show him and point out what i actually need and its not the other bigger coolant fitting its actually the metal S shaped tube that cracked which they said GM does not make anymore?

If you are talking about the large threaded heater hose adapter, I would expect it to be available in brass from a good hardware or plumbing supply store. S-shaped tubes, or other pre-bent heater hose tubes can generally be replaced with pieces of heater hose, again if you are not talking about the special fitting that O-rings into the casting.

Good luck!

If its the S host thats cracked, then you can probally find one at a junkyard no problem. The 3.8 SC series one engine is common on many cars. Just needs a new o-ring on the end and its good to go. And a very easy fix. ITs like a 5 min job when you have a new metal S pipe. But I can't imagine GM not having some kind of replacement around for it. This isn't the same mechanic that said you had to replace the whole LIM is it?

The metal S pipe looks likt this and has a built in braket:
https://2img.net/h/i240.photobucket.com/albums/ff27/karmag3/write%20up/IMGP0491.jpg

well it was a diffrent guy who didnt actually work on my car who said that i needed a whole new intake but today i did ask the acutall guy who worked on my car and he pointed out that i just need the s pipe. however they also took a week looking around and calling junk yards and came up with no luck.

ah, well check around, if you can't find one, I'll check on my old lesabre and see if its got one. In a pinch, and a solution that will take some time; I can always machine you a new one. I'll match the dimensions to the one on my riv since its also a 95. Really its just a tube that the rubber hose can go on, with one end having an O-ring groove, and a braket on the side for mounting. Or maybe see if you can find someone local try to braze the crack on the one you have.(dunno if it would even take it, not sure what kind of metal it is) But those are only as last resorts...

Yah im going to try and see what i can do to it maybe patch it up or something and see how big the crack is this weekend to get a better idea. i also try to call around some junkyards but i dont know how much luck ill get if my mechanic already called all around and found nothing. but at this point im willing to do anything, since my cars just sitting and i cant drive it, which my dad had to take his other car out of storing and let my mom drive it (its a manual) and me take my moms minivan. So if i have no luck from finding one i would def apreciate and take you up on that offer of making one and pay you. anyway thanks for all your help.

sure, see what you can scare up. I was gonna make one for free if it came down to that. Just shipping costs. But of course the best solution would be for you to find one there.

My son was driving my 95 riviera yesterday and the low coolant light came on, good thing because the plastic nipple or whatever it is called broke clean off and spewed coolant everywhere. The part connects into the block or head. it is right above the water pump and uses a hose to connect to the waterpump with hose clamps, a bypass. I need to know what the plastic part is called and whether it screws in or uses some type of compresion ring.I assume it screws in because of the bolt type style the plastic fitting had. I was thinking of using a sprinkler head remover but I want tosee what the new part looks like. Here is a pic of the hole where the plastic nipple goes, thx for any help

not reall sure from the pic where i am looking on the car, plus im not 100% familiar on the 95's but it sounds like you broke the coolant elbow on the LIM.
assuming it take the same part as the series 2 motor this is what they look like.


rockauto should be able to get them for you

Mr.Riviera wrote:

not reall sure from the pic where i am looking on the car, plus im not 100% familiar on the 95's but it sounds like you broke the coolant elbow on the LIM.
assuming it take the same part as the series 2 motor this is what they look like.


rockauto should be able to get them for you

yes - RockAuto lists the Dorman number, larger parts stores may have them around in the HELP section, they are not too $$ you might want to call and ask (after pulling the number off some other web site). . .

Albertj

I found a great article concerning this particular part, check it out...
http://www.automotiveforums.com/t764169-plastic_coolant_bypass_fitting___vin_l_3800_.html

The exact same thing happened to me in my 95. I don't remember what the part was called, but the chevy dealer in town had it for 30 bucks, rip off, but at least the new one was metal instead of plastic.

albertj wrote:

Mr.Riviera wrote:

not reall sure from the pic where i am looking on the car, plus im not 100% familiar on the 95's but it sounds like you broke the coolant elbow on the LIM.
assuming it take the same part as the series 2 motor this is what they look like.


rockauto should be able to get them for you

yes - RockAuto lists the Dorman number, larger parts stores may have them around in the HELP section, they are not too $$ you might want to call and ask (after pulling the number off some other web site). . .

Albertj

I found them at Autozone a few years ago.

I found the part at autozone. Its listed as a heater hose fitting. Its only three bucks but it is plastic. I found a metal version from Rockauto for 4.50 shipped. Ill put the plastic one on for now and replace it later with the metal one when it comes in.


update/// I just came back from autozone and they did have the metal one for 3.99

Yup you found the right one, I really suggest putting int the metal one.

Never saw this write-up before but it is great for all the 95'ers on here! Good job Andrew.

wow! very awesome wright up man! good thing i seen this cause im thinking of now changing my plastic elbow to something more sturdy and this is one of my fears, it breaking( knock on wood) so ill def keep up with this post so in case this happens ill have an idea what to do. thanks!!!!!

BMD wrote:

Never saw this write-up before but it is great for all the 95'ers on here! Good job Andrew.

CHURCH!

More thanks for this thread. This is now added to my list!