: cracked block issue, common??

01-29-10, 08:35 PM
I have a 2000 Deville that I was doing the all too common HG replacement and after everything was put together I noticed that the block was cracked. The crack was near the bottom of the outer bolt holes and went the entire length of the block. I found another block the same year and looked at this one and it also had the same crack. Was this a common thing for 2000? What other years of blocks can I use? Can I use an older block or what are the issues with doing that or is that a bad choice? I need some help/advice, 2 blocks and still looking. Thanks


01-29-10, 09:32 PM
While not entirely unheard of, it is very rare. I don't think you can use a pre 2000 block.

01-30-10, 08:14 AM
Anyone know how new of a block I can use? I saw an 06 for sale, just wondering if it was still the same block. Thanks

01-30-10, 12:12 PM
Ewill would be the guy to answer this. I'll PM him and ask him to have a look here.

01-30-10, 01:16 PM
'06 uses a lot of new hardware, I doubt you can swap parts on that with a 2000.
'00 to '05 should be okay.

Odd that you saw a crack in both engines, are you sure it was a crack and not a casting mark or something?

01-30-10, 04:25 PM
no such luck, it was a crack. Die casting don't get veining like a green sand mold, this block is die cast correct, I thought I read that somewhere. Will a 98 or 99 block work? Thanks

01-30-10, 06:23 PM
98 or 99 won't work. I think mounting points are different.

02-01-10, 08:36 AM
No there are some big differences between 99 and 00, you'll have to go newer.

I have seen some casting flash and imperfections on blocks, if it is leaking something then obviously it is cracked.

02-02-10, 05:08 PM
I have 24 2002 block castings- BRAND new never been used. Factory honed. Send an email to info@northstarperformance.com -

And yes the odd 2000 block has exterior cracking going on, the 93-99, the cylinder walls (mainly from hydrolocking).

02-02-10, 05:12 PM
Ewill - there's a car I just did the HG's on that I believe has an experimental engine in. The grooves in the block for the half-case seals are chamfered on a 45 degree angle- I've never seen this before- have you? I'm used to these grooves being straight like this : |_| and not like \_/. There are some other wierd differences.

My 2004 GXP - the half-case seal grooves don't even reach the rear main seal. They leave a gap where oil can seep out. Poor modification if you ask me. Thank goodness for good RTV sealant.

02-02-10, 05:34 PM
Thanks 97, I may be calling you, I found 1 more core that I am picking up tonight. This is number 3 so hopefully it's a charm.

I do have a good question though. I will be putting insets into the block. Since the inserts are locked in can I use oil on the bolts or do they still need loctite as well? Just wondering what others thought on this, not trying to bring up an insert debate.

Also would anyone feel comfortable using bolts over that were torqued and never ran, I had the heads torqued on and that afternoon the block cracked, I took the bolts out the next day. Just looking for opinions/experience. Thanks

02-02-10, 08:36 PM
I believe you are not supposed to reuse the bolts. They come from the factory with some type of thread locker on them, but see what others say. Not sure if that holds true in your case or not, but DO NOT put oil on them. That will through the torque settings way off.

02-02-10, 08:46 PM
97, I don't do much engine work these days. My hands are wearing out from years of abuse, we have a dedicated department to handle these issues.
I hadn't seen the groove but I wouldn't be surprised if they changed it.
I would have to check but I am not sure they even use the slip in seals anymore, I think they just put RTV in there nowadays.
Don't take my word for it though.

I know our guys use new bolts, not sure if it is a threadlocker issue or a torque to yield issue...I am not really well versed in HG servicing for the reasons I mentioned above.

02-03-10, 12:18 AM
I don't blame you Ewill. When I was really really busy - working 5am-11pm (I kid you not) my hands had to have a few days off once in a while. These Northstars have a lot of sharp aluminum edges too, some like a razor.

The seals were still used in my '04- that's the newest one I've worked on. I can tell you one thing- I will never regret switching to the GM RTV sealant. That's the best stuff I've ever used. I still use rubber seals in the oil pans, but follow that with a bead of RTV. When I tore down a warranty engine today, that little bit of RTV around the outside of the oil pan seal held it down like crazy clue- I had to carefully pry the pan off. Shoot I don't even need bolts anymore :histeric: I'll never use any other RTV sealant again as long as ACDelco sells this stuff.

onestout - if it doesn't work out with that other block, I'll sell you a block (upper and lower) for $900 shipped (UPS ground). Since the threads will be new and installing inserts would be a "very bad idea" IMO, I would go with new bolts and forget about inserts. Sorry but I'm not going to give you advice that I feel may result in failed head gasket sealing. Either new bolts and original factory threads (new block only) or studs, nuts, and washers. I'm sorry if you didn't want to hear that but I will always say this, nobody wants to do the job the 2nd time around.

To date I've had to remove two engines that I had already had out and re-installed. One was for a nick in a cylinder head that I had missed and another was a camshaft that jumped out of position. Oh- and I have to rebuild a 2nd engine for a customer who's engine had been run dry. Of these instances one was almost entirely my fault (so I fixed that at no cost), the second could have been avoided if the customer had taken my advice, so I charged him parts only, and the third, appears to be a lack of oil. I still hold over a 99% success rate. I consider this very good, but even still, doing something the second time around is simply no fun. I don't want this to happen to anyone. Do it once, do it right, and be done with it. I'm learning with my mistakes and if I can help anyone with my experiences, I will be more than happy to pass that info on. I'm learning a lot from these forums and its members as well.

02-03-10, 08:34 AM
The only complaints I hear from heavy duty are when they do timeserts and an extended warranty company will only pay for the ones that are stripped instead of doing them all.
Without fail (or perhaps with fail) when they install the heads more of them start to strip.
Again, sorry I don't know the details.

Years ago I used my fists as hammers to install hubcaps, and I'd snap tissue in my wrists because I was too stupid to walk to my toolbox to get an oil filter wrench.
Now I am paying the price. I use air tools or electric tools for all the mechanical work I do because of the wear and tear and I try to stick to things more electrical and diagnostic oriented. I do OnStar and entertainment systems for the most part, and I back that up with pretty much anything needed on the CTS-V's that come in and all the XLR work you'd think a guy could handle. Not sure how many more of those gas tanks I can take out though, it's tough work.
I spend most of my time staring at my computer looking for electrical issues in the schematics actually.
... but I digress.

If I get a chance I'll ask some of the questions that I see brought up here and see if I can get some answers. ;)

02-03-10, 08:54 AM
Those extended warranty companies are causing themselves problems. If they must use time serts they should at least do every hole.

Ewill - I take it you also test drive those CTS-V's to ensure the problems you fixed are gone? That's a very important part of the job....:D

02-03-10, 10:54 AM
I usually only road test cars when a concern requires that it be driven. I used to goof off a little when I worked for Chevy in the Vettes but usually only in stock units, not customer cars.
If I have the express permission of the owner of the car to give it the juice I'll give it some gas now and then but otherwise... I guess I am getting old.
The new V is really intimidating because there is no concept of how fast you are going and it is really creepy to look down when you feel like you are going 40 and realize that you are... well... not.
That car just has a rediculous amount of power and you really have to be respectful of it or it will bite you.
I really haven't had much opportunity to drive one but when I have... I don't usually do it for long.

02-03-10, 12:34 PM
97- Do you use oil on the nut or loctite for your stud install?

02-04-10, 09:33 AM
Ewill - I was just teasin you - I know we have our professionalism with customers' cars- but that would definitely be the fun part of the job. I had my '04 GXP up to 90 MPH yesterday and I sure didn't feel it- at all - and that's only a Pontiac. I worked with a guy who used to work in the Corvette assembly plant - he said the drivers who brought them to the lot and to the truck would burn the tires right off the line. I find that a bit hard to believe, but when I worked at Cami (where they build the Equinox and Torrent) they sure didn't take it easy on those vehicles at all. WOT right down the parking lot.

onestout - - I personally don't use thread locker on the nuts. The nuts are fine thread and with the torque applied, they will never back off. I do suggest to my stud kit customers that they do put a few drops of thread locker inside the nut to be on the safe side- but it's really not that necessary. The studs stretch just a hair when you torque the nuts down and they are made from an alloy that acts like a bit like a spring and has a memory effect. They stretch to create the correct torque/load and once the torque is removed (upon disassembly) they will be right back to the original length, no stretched threads. I've tested these beyond 90 ft. lbs. and the threads were still not stretched. Basically the stud pulls the nut tight against the washer and keeps it from turning.

Oh - and I never use oil on the nuts- the torque readings would be a lot different.

02-04-10, 11:19 AM
The last SAE paper I read (many years ago keep in mind) required lube (oil or loctite both lube) or the torque numbers needed to be increased by 30%. On the other hand if you have a system that works don't change it. Kinda back where I started. I may have found the design change that has caused my cracking, I'll post pics later if it's as I think it is, I'll be working on it tonight some more.

02-04-10, 12:50 PM
The 1970 Olds 455 GM overhaul manual says to dip the head bolt threads in 30 weight engine oil at installation but that's a cast iron block and cast iron heads. I do not use thread lockers when I stud an Olds 455 or GM 454 block.

Northstar head bolts are supplied with sealant (not thread locker) already "installed", so there's no additional oil or Loctite needed.

Studs are normally inserted finger tight in the block - not torqued in, so there's no additional stuff there, either.

As Jake stated, thread lockers and oils are normally not used on stud nuts. If you use Loctite on the nuts, there's a good chance that the stud will back out of the block if you have to go back into the engine.

02-05-10, 06:23 PM
Actually Sub that is a really good point, Onestout you also caused me to realize something. I'll be changing my instructions. No threadlocker. I haven't had a nut back off yet and if properly torqued, they never will. I've considered locking nuts too but that would also play with torque readings and make disassembly difficult. The taller than average fine thread nuts that I use will be fine, and without thread locker.

02-05-10, 07:09 PM
No such luck in locating a difference in the castings. I did see some cold flow lines on the middle oil drain back passage near the bottom of the block where both other cracks formed, there are a lot of things that could contribute to that and they may have changed things during production without a changing revision. I was able to get the head torqued on that side without a crack forming, so I'm half way there. I also did use the bolts that I had torqued on before, they did not stretch and were the same length as new ones (and I used thread sealer that I typically use on bolts that go into water passages).

02-07-10, 01:32 AM
I had a cracked block in my 00 Eldo @ 85K, a few months and about 3K miles after a time sert & reseal. Believe it or not, this happened exactly 1 day out of warranty. Cadillac had no problem in honoring the warranty, can't same the same for the dealership.

02-12-10, 04:05 PM
Nobe, you have me worried again. I'm putting the engine back in the car tomorrow, hope all goes well. I guess only time will tell if the block will stay together.