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Just finished a Northstar case-half reseal, with pictures


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Hi All,

Years ago this board really helped me out with a P039 torque converter code problem. Now I finally have an opportunity to contribute something. I know that oil pan and case-half leaks have always been a popular topic, so I figured that I would share my pictures of the one that I just completed. I did my first one a couple years ago on a '94 Seville SLS, and just finished up my second on a '93 Seville STS. I sold this car real cheap on ebay a little while ago, figuring someone would buy it for a drivetrain donor, but instead it's new owner is putting it back on the road. I had disclosed the oil leaks in the listing, but the buyer was not familiar with the cost of the procedure. I offered him an unbelievable-super-good deal on repairing the leaks, and since there aren't any decent mechanics where the seller lives, he had me repair alot of other issues on the car. The car has certainly come a long way. The dash used to be lit up like a Christmas tree with warning lights, and the message center was constantly scrolling an endless stream of trouble messages. The only warning that wasn't on was the air bag. Now I'm down to just "low washer fluid", which I'm assuming will stop when I fill the reservoir.(I left the easiest for last). Sometime next year I'll be installing a '95 SLS drivetrain in my '94 STS. I've learned quite a bit about these cars and many of the subtle changes that they made from year to year, and I know I'm going to run into a few issues with the swap, but not the obvious ones that first come to mind. Well, that's enough chit-chat, here's a link to the pics:

http://rides.webshots.com/album/573977369awUtwy

Jeff

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Very nice job Jeff!, you pay lots of attention to details.

Did you replace the main bearings? How did they look? Did you keep the main bearings in their respective places by marking them, if you didnt replace them?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thanks guys for the compliments.

I did replace both the main and rod bearings. I couldn't find any info on how to read these newer aluminum bearings. When a traditional bearing insert is down to the copper, you know it's time for new ones. The thrust side of the bearings were worn through the dull coating, and looked like shiny aluminum to me. I mentioned this to the buyer, and he decided to go for new bearings, which weren't cheap, about $250. You run into a dilemma on the Northstar if you wish to check bearing clearances: The main bolts and rod bolts are torque-to-yield. How many times do you want to stretch them out without replacing them? The mains are a pain because they don't have individual caps, just the lower case half. I plastigaged all the mains, and one rod on each crank throw when I installed the new bearings. When I did this, I only tightened the rod and main bolts to about half their final torque value, to avoid extra wear on the bolts. This may not have given me a 100% accurate reading, but it was good enough to let me know that there weren't any major problems with the new bearings. Before I took the engine out, the bottom end would give a good rattle when you first started it up, and I was hoping that the new bearings would eliminate this. Unfortunately, it still does it, and I think it's just the nature of the beast. The oil passages that feed the bearings are cast into the lower case half, and they are HUGE. I suspect that they drain down when the engine is off, and it takes a second to pressurize these passages when the engine is started. The old-technology electric motor idle control, that guns the engine when you first start it, probably doesn't help things either, especially since these engines have a very short crank time before they fire. I would bet that the '96 and up Northstars with the air bypass idle control don't rev up so high when first started. I know that these engines have some piston noise too, but this one quiets up to fast to be that. Other than the initial second after starting, the engine sounds great. It's almost silent when it settles down to base idle.

Jeff

Edited by bigmoparjeff
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how long did it take you to do this????? I would like to have mine resealed and stuff but there is no way I could do that Plus I don't have the tools required... How much would you think that would cost say cadillac dealer and non cadillac person just a good machanic.... which would be the best route for me to take... I only say this becasue I just like my rides to be 100% or as close to it as I can get.... Also what is the process to taking out the air compressor could you advice me on the steps I need to take to accomplish this....?

Thanks alot...

By the way VERY NICE JOB ON THAT CAR YOU REALLY KNOW YOUR STUFF..... IF YOU ARE CLOSE TO LANSING, MI OR MISSISSIPPI i would let you do mine that way also....

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Thanks for the accolades! To do the reseal in a meticulous way, it takes me about 30 hours for the whole job. This particular car took a lot longer because I had to find and recondition another subframe, plus it got many additional repairs while the engine was out and things were easy to get to. From what I've heard, book time to do the job is around 24 hours, which equates to $1700 to $2400, depending on the labor rate of the shop, plus about $500 in parts. Cadillac dealers were charging around $3000 to do it, and many of them were not removing the engine from the car, which in my opinion, compromises the quality of the repair. It may take some searching to find a private shop that is willing to take on a Northstar case-half reseal. Many shops won't touch a job like this, because if anything goes wrong and it has to come back apart, they stand to loose all they made on it and more. Simple work like brake jobs and front end repairs have a much higher profit margin, so unless a shop is hurting for work, it's just good business sense to steer clear of big, difficult jobs. I could do the reseal for $1000, plus parts. I'm booked solid through the end of the year, but will need to line up new jobs for winter 2010. I'm near Philadelphia, PA, so I'm not close, but not terribly far from Michigan. If you're interested, you can e-mail me directly: moparjeff@aol.com

The A/C compressor is not too hard to remove on cars without an oil cooler. It's a tight squeeze with the oil cooler lines in the way. The older STS's had oil coolers, SLS's did not. I don't know if they still used separate oil coolers after the 1998 re-design. If you decide to have the engine resealed, the A/C can be done at the same time, since the system has to be discharged, and the compressor removed to repair the engine. To remove the compressor, the system needs to be discharged first, then the belt removed. The hardest part is loosening the bolt that attatches the lines to the back of the compressor. You may not be able to get a socket on it until after the compressor has been unbolted from the engine. There is a bracket on the back of the compressor that is attatched to the engine with one nut, then there are three bolts on the front of the compressor that attatch it to a mounting bracket. They can be seen by looking straight at the front of the compressor, through the wheel well. When free from th engine, the compressor comes out through the open space in the wheel well. It just fits through on an SLS, the cooler lines may be an obstical on an STS. If it won't fit through, the cooler lines will need to be disconnected, or the right front corner of the sub-frame dropped down to provide the required space. The older Sevilles had a small access panel on the radiator support that unbolted, to give you a little more working room. I don't know if the '98s have this feature. If the old compressor failed mechanically, the system should be flushed and the orifice tube replaced. The accumulator should be also be replaced when installing a new compressor. Before the system is recharged, it needs to be evaccuated for a half hour with a special pump. And my final tip: Be wary of remanufactured A/C compressors and Chinese-made new compressors. They are both of dubious quality. Genuine GM is your best bet for this job.

Jeff

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