: Cracked Block, exterior, 1997 Northstar

06-21-08, 03:07 PM
Hi Everyone,

I am a new member and really hope one on you graduates in the Northstar school of ownership and repair can educate me.

I have a 1997 STS, Northstar engine which started seeping antifreeze. My repair guy spotted a 2" crack at the front of the block that seeps about 1 gallon on antifreeze per month. I tried the guanteed fix em up chemical weld products but they did not work. My buddy says if its aluminium and not an internal leak, and we can get at it why not weld it. This is an external seeping leak only at the front of the block so it has semi easy access to weld.

Has anybody ever tried to do this and what type of perils did you encounter.

Thanks, Wayne Banks

06-21-08, 04:00 PM
Hey Wayne,

Welcome to the forum. This is just to post questions about the forum, you may want to try and post this in the "cadillac engine Technical discusson" forums. I don't know the N* but there are a few around here that know it well.

Good Luck!

06-21-08, 04:47 PM
welcome and please post questions in the proper forum for your vehicle

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06-21-08, 05:26 PM
It might be doable. Make sure you get someone experienced in heliarc welding and be sure to remove the ground cable.

06-21-08, 07:24 PM
I would take out your PCM just to be safe.

06-21-08, 07:57 PM
i dont see why it wouldnt work...

06-21-08, 08:53 PM
If you try a heliarc, make double damn sure the equipment ground is very close to the weld site, on the block, and not on some mount bolt possibly insulated from the engine. The LAST thing you need is a few hundred DC/AC volts dancing around in a module.

CTSV_Rob is right on target.

06-21-08, 09:51 PM
JB Weld!

(just kidding)

06-21-08, 10:20 PM
Thanks for all your advice, I think I am going to try and have the block welding and I will let you know how it turns out.

Wayne Banks
Toronto, Canada

06-21-08, 10:50 PM
:mad2: You can't weld it.

I have done it, but it took too much effort.
The coolant that was trapped inside the crack kept contaminating the weld. :annoyed:

The first attempt


06-22-08, 09:49 PM
I've welded hundreds of aircraft cylinder heads. You have to vee out the crack using carbide burrs in a die grinder and Pam spray to keep the burrs from loading up. It's best to preheat but if you can't, TIG weld short sections and peen the weld with an air hammer to control shrinkage, warpage, and recracking. You need at least a 300 amp welder with a foot operated heat control. I use a Lincoln TIG 300/300. After 20 or 30 trys it gets easy.