View Full Version : Help With My 99' N* Hg Job

08-16-07, 09:43 PM
The head gasket job on my99,000 mi 99'STS is about to begin. Having A.D.D. its hard for me to "skate" aroud this site to obtain all the tech info. I've been thru most, but its hard to remember where to go to re-visit. I thought it would be helpful to me and others, to be able to go to one thread to obtain the info that is needed. There also seems to be some descrepencies regarding certain aspects of the job, and maybe some final conclusions as to the best approach will be found.
This is a brief description of where I am at, and what I have concluded by visiting this site.
I'm dealing with a 99' block, the last year before the block casting methods were changed. Porosity is common on the blocks prior to 2000. It seems the majority of opinions, even with the 99, in to insert all the head bolt threads. I have decided to do all, and am leaning towards the NORM's NS-300L inserts. Opinions on these inserts is welcome, especially for the 99' block. I'm open as to which headbolts to use, stock GM or aftermarket such as ARP. Advise that I read somewhere, was to use Fel-pro HG's, as they were superior the the stock GM gaskets. Even tho not recommended by fel-pro, I received some advice somewhere, to use the copper head gasket sealer. ??
. A back disability is standing in the way of doing it myself, but having chose a local "smalltime" mechanic to do the job, it will still enable me to get my hands "dirty" , and monitor the job. More than likely, I'll be doing the inserts as well as alot of cleaning and gasket replacement, that typically would not be done on the normal HG job. Following reccomedations on this site, we will be "pulling" the cradle to do the job.
Although my mechanic has never done an N*, his experience with other 32V interference type motors, SVT Cobras, Jags, and others, I have full confidence in his abilities. Personally, I'd prefer to open it up, check things out and replace all the bearings, but because of my disability, but pocket appears to be empty. Upon advise I receive here, I may look at doing some addtiional work, if it is reccomended. It appears as if an extended warranty company has concluded that this repair fall into thier "covered repair" class, but they refuse to have any part in helping with any insert costs. I think they will eventaully have to give in, as they also want the repair shop to warranty the work for 12,000 miles. My local Caddy dealer won't touch it without doing them all, so hopefully this will put some added pressure on. Maybe someone has some "choice" wording for me to use on the x-warranty people.
Hopefully this thread is appropriate, as I am fairly new since having this HG problem. I commend you "guys" and this site, for the wealth of information it has. Have at it....pick me apart !!

08-17-07, 10:46 AM

As you mentioned, a lot of advice is opinion, and does not eliminate another process.

Norms inserts look to have an advantage. They are longer which I liked, plus they have may have a better thread. That doesn't mean timeserts are unacceptable. Timeserts have worked in lots of engines without a problem. It comes down to preference and cost. I have a timesert kit available to me so I'm only paying for inserts. I'll stick with timeserts at this point.

The same with gaskets...I used GM and had no problems. I decide based on cost and availability. I used to use various products to help seal the HG's. I haven't lately (years lately).

If the mechanic has any OHC experience he should have no problems doing this job.

Opening the bottom end was not recommended. The "guru" that used to be on the board said if you look at the bearings you had to replace them. They tend to spin if the tension was released. The rotating assembly should last 200K + with any decent oil changes.

I assume you mean dropping the cradle. Definitely the easier way to do it.

You may want to change the half case seal but that means separating the engine from the trans and would be more work. I think it can be done on a lift easier. One of the pros can chime in on that.

Here's a writeup after the first one I did. I never did part2.


08-31-07, 12:15 AM
Well, got an update on my car...mechanic called tonight and he removed the front head as the x-warranty people wanted him to do. He said all of the bolts were tight, but could see where the gasket was leaking in #4, as that was the cylinder that I had diagnosed was leaking into the cooling system. He seemed to think all of the threads were ok and just the gasket failed, but I am going to do a thorough check in the morning. If they do appear fine, I'm really confused at what to do at this point. Before, I was convinced and had decided to do all 20, using the Norm's inserts. I thought maybe that if they visibly appear ok once I have them cleaned up, that I would try a new, uncoated bolt in the holes, to check for any distortion. Then again, maybe I shouldn't worry about "wherther" they are distorted, and just go ahead an insert them all like I had originally planned. Advise ??

08-31-07, 05:45 AM
If it was mine.... and I had it apart, I would MOST DEFINATELY put the inserts in it.

With all I have heard, it wouldn't be worth it to take a chance on the threads.
The inserts themselves don't cost that much when you consider the cost of maybe having to do it over.

Jim from Texas

08-31-07, 11:51 AM
Do the inserts now, rather than in another 10,000 miles.

08-31-07, 12:25 PM
If it was mine I would do the inserts.

10-02-07, 03:43 PM
It has been a slow process because I have been so busy, and I finally got my part of the job done. Fortunatly, I've been working with a shop that is doing the HG job as part of an extended warranty, but they were willing to alloow me to do the inserts to help save some money. The inserts I chose were Norm's, and although the engine is not complete, the "sert" job is done, and it reasonably well. I found the Norm's system very easy and straight forward to use, and with the coase thread holding design, I don't anticipate and torquing or failure problems. I would definitly reccomend using them. Anyone out there know if there is a good online source, for the front motor mount ?
Thanks, Jim

10-02-07, 05:31 PM

10-15-07, 04:25 PM
HELP !! I'm about ready to throw in the towel. The Norms inserts were in, and thought we were down the homestretch. I left town for a week, and the plans were, that my car was to be done when I returned. WELL, it wasn't. My mechanic informed me that a couple of the inserts were crooked, and the headbolts wouldn't go in !
Even though I am disabled from a failed back surgery, and have to take morphine twice a day, I will still take the blame. I was working thru the radiator hole when I done the front bank because of the lack of room to slide the cradle completely out, which attributed to the problem . I still don't understand it, because I used the "tap block" that Norm's supplies, on every hole, and never had an issue at the time I tapped the holes. Anyway, all that aside, I need a solution. The rear head went on fine. A couple of the bolts seemed to be bent from trying to force them in, so I am certain I need a new set of bolts ?? It seems I should probably pull the inserts to check them also. To me, it seems the only solution at this point, is to open up the problem bolt holes in the head a little. I screwed the bolts in the block to check the alignment, and they are not off much. The factory holes in the head leave around .035 clearance around the bolt, and doubling that would take care of the problem. The 17/32 bit used for the inserts would be real close to that, and enough clearance would be achieved by opening them up,about half the way down toward the block (drill 1-1/2" deep) Am I dreaming or looking for an easy way out, or what do you guys think ? AJ....Have you ever had that problem ?? (Pulling my hair out!! Not much left !)

10-15-07, 08:02 PM
Are you reusing the original bolts? Not recommended although they may work. They are not TTY but have special coatings on them.

I don't think you can bend headbolts trying to force them in...they are pretty big. If they are bent you have an additional problem.

I'd lift the head off, insert the bolts in the holes with the HG on the block and see how they are positioned. If necessary I'd just enlarge the bolt holes that are out of position.

10-15-07, 08:05 PM
You said you inserted the bolts in the block...to clarify...

Did you have a HG on to check spacing?

Did you install all at once to check angle to the block?

10-15-07, 10:16 PM
Are you reusing the original bolts? Not recommended although they may work. They are not TTY but have special coatings on them.

I don't think you can bend headbolts trying to force them in...they are pretty big. If they are bent you have an additional problem.

I'd lift the head off, insert the bolts in the holes with the HG on the block and see how they are positioned. If necessary I'd just enlarge the bolt holes that are out of position.

Nope...not using the originals..it was a new set...and they definately bent. I scoped it out further since I wrote about the problem, and it appears as if there maybe 4 that are off a little. I plan to drill those 4 out ,half way down from the cam side of the head , and that should take care of the increased angle..about 1/16 off. There is about 1/32 clearance that done from the factory. I was super careful on the drilling. Norms' might need to think about providing a jig like Timesert for better alignment. Hopefully there is not a water jacket clearance problem, in driilling the headbolt holes oversize. My son looked it over and don't think there will be a problem. He is a former drag racer, with considrable experience in head porting etc. Any other info and opinions are surely welcomed !!

10-17-07, 12:52 AM
Hard to imagine the hole being drilled crooked with all the care in designing a tool to prevent that! Non the less, I might consider using ARP studs and drop the head down over them. If it drops to the block, fine, if it hangs, drill the offending head holes oversize. The offending crooked holes should be easily visible, with the straight studs providing a good reference to head orientation.
Removing the inserts will require oversizing the holes, not a good idea as block strength will suffer.

Good luck,

Jim in Phoenix