: removing northstar engine AC COMPRESSOR question



jacks93STS
08-07-05, 01:03 PM
Hi, this is my first post, but i am pulling the engine on my 93 STS with the Northstar...i blew a head gasket, i am ready to pull the engine other then one small problem..the manual calls to unbolt the AC Compressor and move it out of the way...i can not find how to do this? i have unbolted the 3 outside bolts, but it will not budge, there was one rear bolt attached to a bracket i removed as well...the rest of the bolts i see hold in the AC compressor lines, which i have not disconnected because i think it will let the freon out...i have not done a conversion and i dont really want to, is there a way to move the compressor aside without drainging it or is it impossible? Any help would be appreciated, then i can get on with this project and timesert the headbolt threads replace all my gaskets and get on with my life haha

JSMeloche
08-08-05, 09:35 AM
I dont think there is a way to remove the engine from the car without disconnecting the A/C lines. A conversion is pretty common these days and simple. You probably will need a dryer, and a refill kit, I recommend having it refilled at a specialized place, where they can put dye and look for leaks etc...

If I recall correctly (search my post for a complete detailed A/C compressor replacement) there should be 2-3 bolts in the front of the engine and one on the side, behing the compressor. This one is a bit hard to get to. I finally got it with 2 long extension and sliding a ratchet from the front of the car

jacks93STS
08-08-05, 11:19 AM
i might as welll...it would make things easier i guess. as soon as this thing is out of my way i can lift the engine, everything else has been removed, i just didnt want to fork out any more money then needed. This project is already totaling well over a grand, but i guess its alot cheaper then the 10,000 cadilliac wanted for it (they said they wouldnt fix the headgaskets because of the headbolt threads, when i asked them if they timesert they said no, they just put new engines in) so im doing the job myself
thank you though, ive been stuck for a couple days

Jack Ammann
08-08-05, 01:30 PM
jack93STS....the only way I've ever seen an A/C compressor removed is from the bottom of the car. :bonkers:

kingphil69
08-13-05, 07:34 PM
hey... forget the conversion if you want... im in atlanta, and have R12 available. not the fake stuff either. if you want, let me know. kingphil69@yahoo.com we can figure somethin out. just say your from here, and a link to this thread if possible. thanks,.

growe3
08-13-05, 08:45 PM
You do not need to dismantle you AC, to remove your engine. Just remove both fans and the radiator and the AC compressor will just set on the frame, still charged.

Of vital importance is to get a set of the factory service manuals, or you will most likely not be able to successfully repair your engine, and/or will damage many components in the process of your repair attempts.

I have repaired both of my 93 STS's and although I have a lot of experience building engines and other auto modifications, the Northstar engine takes some special knowledge to repair properly.

With the factory service manuals and patience, you can do the job.

I repaired both of my cars by pulling the engine from the top; it can also be done from the bottom, with I feel, a higher level of difficulty.

To make it a little easier to control the engine, get an engine leveler to allow you to angle the engine when removing or replacing it.

Use an engine stand to do the TimeSerting and other cleanup on the engine.

Be patience, clean, use the manuals, post questions back here, and you should be able to get the job done.

-Good Luck, George

93sts100k
08-13-05, 11:24 PM
growe3 is it really easier to remove just the engine???????? ive only heard the opposite. please respond, im about to attempt and want to take the simplist route.

growe3
08-14-05, 12:17 AM
In my opinion, yes.

You might get a 50/50 response on this, but I definitely would do it from the top.

There are difficulties either way; mostly it is a tight fit in the engine compartment. Either way you have a lot of wiring and hoses to disconnect.

I personally don't feel comfortable removing all of my suspension etc., just to get an engine out, if there is another reasonable way to do the job.

Removing the engine from the top is easier for the home mechanic (I think), than dropping the cradle with suspension attached and then raising the car body high enough to slide out this heavy, unwieldy assembly.

Now in a fully equipped shop with a car hoist, dropping the engine cradle etc. would likely be a better way to do it. Most others and I, work out of a home garage or driveway, to me it just is a lot safer and easier to pull it from the top. No special tools or other apparatus to do the job, just conventional tools.

I do strongly advise getting the factory service manuals if you do not already have them. This engine is not that hard to work on out if the car, but,.....you must do the disassembly and reassembly according to the book, or you will damage items or have a miserable time trying to figure out how to deal with this engine. With the manuals it is pretty much follow the directions, and the job will work out fine.

No matter which way you decide, allow more time than you think it will take. Not having to rush will increase your chances for a good, long lasting repair job.

-George

93sts100k
08-14-05, 12:26 AM
thanks for the advice. im going to look at it and try to make a decision as to what is best for me. i have chilton's andthe haynes manuals but in your opinion i still need the shop manual? was it hard getting to the transmission bolts?

growe3
08-14-05, 12:44 AM
Chiltons is a good manual, for blocking the door open, but that is about it in regards to the Northstar engine.

Get the Helms service manuals, they are the one that Cadillac uses. Aside from the engine information they contain a wealth of information on the rest of your car.

These manuals are getting harder to find, I located a set on EBay.

I recommend snapping them up with the "Buy It Now" option.

These are offered at $55 (my cost was $90 for a new set).

1993 Cadillac Manuals on E-Bay (http://cgi.ebay.com/ebaymotors/1993-Cadillac-Eldorado-Seville-Factory-Shop-Manuals-Set_W0QQcmdZViewItemQQcategoryZ34212QQitemZ7992485 509QQrdZ1QQsspagenameZWD1V)

growe3
08-14-05, 12:05 PM
Regarding the transmission bolts, they were not particularly hard to remove. Just note that the rear bolt is shorter then the other three bolts. There is a ground just above the rear transmission bolt that is awkward to get at. Be sure to reattach this ground as soon as you can when putting the car back together. It gets buried real quick, and then is very hard to get at.

The hardest bolts to remove and replace were the exhaust pipe to exhaust manifold bolts. You need to spray them thoroughly with penetrating oil (preferred) or WD-40 and let them set overnight. It will take a couple of long extensions to be able to reach them. Although they are all the same diameter bolt, two of them have smaller heads (10 mm), to give a bit more clearance for the socket.

I would advise taking lots of pictures of the engine compartment before removing anything. The area around the throttle body is of particular importance, due to the many wires and tubes in that area. Whenever you can during disassembly, take pictures of areas that look complicated, to aid you on reassembly.

After you get the engine out and apart, if there is anything that needs replacing in the engine compartment now is the time to replace it. Inspect the heater barrier cover, on many of the earlier cars it becomes very brittle and will literally crumble in your hands. It will cost about $80 or so, but it cannot be replaced with the engine in the car.

Use only OEM parts and gaskets. The head gaskets are very special material; almost all of the rest of the gaskets and seals are special material with raised silicone beads or silicone gaskets. This engine sees heat that would cripple most engines, on a daily basis, so using cheaper aftermarket gaskets would be a big mistake.

I bought all of my OEM parts from GM parts Online. They are about 35% - 40% cheaper than going to a local dealer. Very helpful counter people.

GM Parts Zone Online (http://www.partszoneonline.com/Frameset/frame.php?link=4)

This link is to my web storage, there is an Adobe .pdf at the bottom of the list,that contains a list of what I had to replace. I would expect you to have similar needs. You may find a few of the other files of interest also.

Headgasket Repair Parts List (http://f2.pg.briefcase.yahoo.com/bc/growe3@pacbell.net/lst?.dir=/1993+Cadillac+STS+Information&.order=&.view=l&.src=bc&.done=http%3a//f2.pg.briefcase.yahoo.com/)

-George

Pjs
08-14-05, 01:28 PM
I recommend dropping the cradle. I know a few have done it through the top but knowing everything the has to come off, motor mounts, wiring harness and such I think having the engine sitting open on the cradle affords you great access which allows you see exactly what your doing. As far as the suspension as Growe mentioned, all you have to remove are the 6 stut tower nuts, calipers and linkage and the suspension will stay with the cradle. Word of caution though, once the car is lifted up, Tie a rope from the top of one strut to the other to keep the CV joints in line. Failure to do this will allow the axle to drop far enough to pull the CV boot loose and the joint will separate. If this happens you have to take great care in realinging the joint. It's not a big a deal as it sounds but definitely something to watch for.
I ended up making a cradle dolly from 2X4's, lag screws and large wheels. I picked up an engine hoist on sale @ Pep Boys for $125, which I've had several occasions to use and have definitely gotten my money out of it.
Here is a thread from when I first pulled mine w/ pics...

http://www.cadillacforums.com/forums/showthread.php?t=23672

Lining up the cradle for installation isn't that difficult but you should mark the rubber insulators position where it rests on the body because if your not dead on when you reinstall it you'll have to a realign the front end .

It took me 3hrs to have the cradle down the first time and less then 2hr the second time.

Which ever way you decide to tackle this is up to you. Good Luck :D

zonie77
08-14-05, 03:32 PM
I also feel it's easier to drop the cradle. This is the was GM designed it. The only reason to pull it out the top is if you have limited room to work. Do it the way you are comfortable.

Growe3 likes pulling it from the top, some of drop the cradle. It can be done either way.

There are good instructions either way.

93sts100k
08-14-05, 05:55 PM
Man!!!!!!!!!!! You guys are really a big help to me. I know its still going to be a challenge, but with all the info you all so freely give, my options are more open and im more confident.Im in the process of trying to find a shop manual on ebay. Im still not sure which way Ill try to pull it but if I come out the bottom Ive got to build that contraption that Patrick built(pjs). Zonie77, Growe3, Pjs, I really appreciate the efforts to help make this job easier for me. Thank God for the computer because you dont find many people willing to help w/out expecting something in return.

93sts100k
08-14-05, 06:07 PM
Growe3, I tried to open the link, Headgasket Repair Parts List, and I kept getting can not find server.Is there another way to access it? I looked at those exhaust bolts,and they do look extremely hard to get to, but i guess not impossible. The wiring harness to the right doesnt show where it disconnects?????????????Am I missing something? I almost forgot how long did it take you pulling the engines out the top??????

93sts100k
08-14-05, 06:18 PM
:banghead: I know this is 3 in a row but what do you guys think about this. There is a machine shop here in town (shreveport,la) that will timesert the engine for me w/guarantee for 500 dollars.theyll have it ready same or next day. they will only take the block. if i come out the bottom i will still have to take the block off the trans. there is a shop in dallas that said they would timesert it on the cradle for 1000(out of the question) the kit cost 411 i hear so i thought 500 was good and if theres a problem theyll big sert the problem free. im barely leaning toward coming out the top(scared of tight spots, have big hands so barely) definetly leaning toward taking the block for 500 . When I stopped by they had 2 waiting to be picked up and they looked good. they say they havent had any come back.

zonie77
08-14-05, 07:15 PM
If you are buying a new timesert kit the cost is pretty close. If you are gonna pull the block out of the cradle I'd do the block seals (tiered block) right away, even if it's not leaking.

If the block isn't leaking and you get a used kit (that you can resell) I'd do it myself. It isn't hard to do, just tedious. If you set up right it goes pretty fast.

What kind of location do you have? If you have both sides of a 2car garage I'd drop the cradle. If you are gonna pull the engine apart (more than the heads) it's a little closer.

zonie77
08-14-05, 07:23 PM
If we're talking the same harness, it unplugs from the computer, under the glovebox. The newer ones seperate in the engine compartment.

93sts100k
08-14-05, 07:50 PM
Ill be doing it at home. behind my house ive got asphalt and a cover about 10ft high, open on all sides but large enough for about three cars. I was talking about the harness that comes out under/near the master cylinder. After youve done all this work does the car still run as strong as it did before. i hate even having to touch it.

zonie77
08-14-05, 11:42 PM
The two we did ran good before, just overheating and coolant loss. They probably ran better after but the difference wasn't that great.

After you could drive anywhere without worrying about getting there and back!!

93sts100k
08-16-05, 10:15 PM
my car was running hot and loosing coolant, but still ran really strong. ive been cranking it everyday, but today it was hard to crank. it turned over once gave a hard pause and then turned over several more times before it cranked. i noticed a nice amount of water out the tail pipe, and now water is in the oil. do you guys think i messed the gasket up worse than what it was, or does it sound like i cracked a head?????? it seems as if water was in a cylinder when i cranked it. what damage could that cause????????????

zonie77
08-16-05, 11:13 PM
It is possible to hydrolock an engine. That can cause connecting rods to bend. It doesn't ssound like that happened though.

It is also possible to ruin the bearings with water in the oil. This is much easier to do. If you see water in the oil it is way past time to replace the oil.

I thought you were in the process of disassembling it?

Mark Bunds
08-17-05, 12:24 AM
my car was running hot and loosing coolant, but still ran really strong. ive been cranking it everyday, but today it was hard to crank. it turned over once gave a hard pause and then turned over several more times before it cranked. i noticed a nice amount of water out the tail pipe, and now water is in the oil. do you guys think i messed the gasket up worse than what it was, or does it sound like i cracked a head?????? it seems as if water was in a cylinder when i cranked it. what damage could that cause????????????

It's time to stop driving that car if you don't want to replace the entire engine.

93sts100k
08-17-05, 10:23 AM
i am waiting on the shop manual. i have just been cranking it everday and letting it run a few minutes, didnt know it would hurt. i guess ill find out when i open it up if anything else is hurt.how would i know if i hydrolocked and bent connecting rods?

zonie77
08-17-05, 11:24 AM
Don't run it anymore you are only damaging the engine. Drain the oil to get the coolant out of the bearings.

Mark Bunds
08-17-05, 11:32 AM
i am waiting on the shop manual. i have just been cranking it everday and letting it run a few minutes, didnt know it would hurt. i guess ill find out when i open it up if anything else is hurt.how would i know if i hydrolocked and bent connecting rods?

If it cranked and started the last time, chances are you haven't hydrolocked it.

Hydrolock happens when enough coolent (or any other liquid) enters the cylinder and fills it enough to cause the piston to "crash" when it begins the compression stroke.

Because the intake and exhaust valves are closed during the compression stroke, any amount of fluid in the cylinder equal to or greater than the total headspace at TDC (actually less fluid can cause lock because only a certain amount of air can be compressed with liquid filling some of the volume) will cause the piston to stop suddenly because fluids are non-compressable.

The damage is negligible if the starter only drives the piston into lock, but if another cylinder fires first, the power could cause serious damage to the locked piston/connecting rod. If there is just enough fluid in the cylinder to lock the piston near TDC, the chances of damage are greatest because the closer to TDC the crank gets, the greater the forces it imparts to the rod because of leverage.

Usually, hydrolock acts like a seized engine with no damage, and can be relieved by removing the spark plugs from the affected cylinders. You can check for a seriously bent rod by using a micrometer depth guage to measure the distance from the top of the block to the piston head at BDC. It is very unlikely that more than one rod would be bent, and impossible for more than two to be bent. When you remove the heads, make a note of which cylinder/s was/were breeched by the blown gasket. Clean the block throughly. Turn the crank and measure the depth to the pistons at BDC of all 8 cylinders and number them. While doing this, remember to tap each piston lightly with a block of wood while at BDC before taking your depth measurement as this removes any slack between the connecting rod wrist pins and crank bearings.
Take the average depth of all of the cylinders that were not breeched; this will be your target depth. Compare the average depth measurement to the the depth measurement of the suspect cylinders. If the depth of the suspect cylinder/s is greater than the average, you have a bent rod.

93sts100k
08-17-05, 01:04 PM
thnks for the info. i will check that when i break it down. the engine did run after cranking with very light miss, almost not noticeable. hoping for the best, maybe the gasket blew out more, like more around the cylinder????? if a rod is bent how hard is that to fix and is it worth it?

zonie77
08-17-05, 01:41 PM
While it is possible to bend a rod I don't think you did by cranking it. Definitely check by verifying height. Mark gives you a good way, I would probably check at TDC but it's basically the same. Check to the center of the piston so you get a constant reading. A few thousandths isn't an issue as that's probably production tolerances but anything substantial is an issue.

It should be one of the leaking cyls that shows low if it hydrolocked.

93sts100k
08-17-05, 01:51 PM
i forgot to ask, is it possible i damaged the head ??????? cant wait to get my book, im sick in the stomach and cant sleep. should i start taking it apart what i know how to do, are is there any special prep?

Mark Bunds
08-17-05, 02:21 PM
thnks for the info. i will check that when i break it down. the engine did run after cranking with very light miss, almost not noticeable. hoping for the best, maybe the gasket blew out more, like more around the cylinder????? if a rod is bent how hard is that to fix and is it worth it?

Maybe this will give you some idea:

I have rebuilt my share of old-school Ford and Chevy engines, but never a Northstar so I don't know how much of the following is applicable.
If your engine has any major amount of mileage on it, you may need to install oversized rod bearing inserts to compensate for normal wear. If you do one, you should do them all. And if you discover more wear than the engine specs call for, you might as well do the crank mains as well. If you have the crank, rods, and pistons out, you might as well hone the cylinders, which means you may have to install oversized pistons, and you will have to resize the rings. This means that when you are finished, you will have rebuilt your entire block.

Once the heads and oil pan are removed, the mechanical procedure for removing and replacing rods and pistons is fairly easy if the piston will come out of the top of the block.
On higher mileage engines, normal wear can cause the cylinder to form a ridge right at the top where the rings stop on the upward stroke, making it impossible to pull the piston out of the top of the block.
This means that you will have to remove the ridge, or the pistons will have to be pulled out from the bottom, which is impossible if the crank is in the way, or if a ridge has worn there as well.
Once the crank, pistons, and rods have been removed, cleaned, and inspected, some technical details are involved in sizing the bearing inserts for the fit of the rod to the crankshaft.
The engine specifications will give you the optimal clearance necessary for the bearing tolerances, and you will need either an outside/inside mic set, or a plastiguage set to discover the right size inserts to use. These measuremants are critical; too tight and the bearings will seize; too loose and the rods will hammer the inserts to pieces resulting in catastrophic failure. The same goes for sizing the new pistons and rings; the dimensions are critical for long wear and proper performance.

It is a time consuming and exacting job, but if you follow the steps for rebuilding, it really isn't hard.

Is it worth it? Well, when the job is done, and you know you didn't take any shortcuts, you can be certain in your heart and soul that it was done right; something you can never know with a short-block installation, shop rebuild, or used engine installation. Plus, you saved about $3000.00. And when it's all finished, and you turn the key, and that engine roars to life, well, there's no feeling quite like it, because you brought that engine back from the dead, and you are more intimate with it's inner workings than most of your friends will ever be with theirs.

Mark Bunds
08-17-05, 02:32 PM
While it is possible to bend a rod I don't think you did by cranking it. Definitely check by verifying height. Mark gives you a good way, I would probably check at TDC but it's basically the same. Check to the center of the piston so you get a constant reading. A few thousandths isn't an issue as that's probably production tolerances but anything substantial is an issue.

It should be one of the leaking cyls that shows low if it hydrolocked.

We checked 16 cylinder GM diesels used for co-power generation at BDC because we were inspecting the cylinder walls and ports at the same time. These things had the nasty habit of hydrolocking when an injector would stick open while the machine was in standby, usually because some dweeb did something stupid to the filters. TDC would actually be easier.

zonie77
08-17-05, 07:06 PM
Start taking it apart.

All the wiring necessary to remove the engine needs to come off. If you've never done this before an important thing to do is picture reinstalling it as you remove it. Is there only one way it can go on? Are all the connectors different? If there is any doubt start labeling things, if it can only be installed one way there isn't need to label. Take some pics as you go. If you have a helper assign one of you to picture duty.

If you read my thread I suggested getting a bunch of cheap plastic dishpans to seperate parts. Again, if you don't have a lot of experience, or if the project may drag, this is real important. My brother insisted on this and it really helped. No digging through 50 bolts to find the right ones. Each pan held one assembly or side of the engine. (Personally I missed all the cursing that went with all the bolts in one coffee can!)

I'm still recommending dropping the cradle. You can start taking things apart. You don't rally need the manual til you have it apart.

93sts100k
08-17-05, 11:27 PM
thats what ill do. i have done this before but on a 3800 v6 at about 175000 miles, its at 304000 miles now and still runs good. i will also use alot of containers because im positive it'll be worth it in the end. ill probably start tomorrow. after i get it going ill decide top or bottom. thanks again everyone!!!!!!!!!

Pjs
08-18-05, 07:14 AM
Maybe this will give you some idea:

I have rebuilt my share of old-school Ford and Chevy engines, but never a Northstar so I don't know how much of the following is applicable.
If your engine has any major amount of mileage on it, you may need to install oversized rod bearing inserts to compensate for normal wear. If you do one, you should do them all. And if you discover more wear than the engine specs call for, you might as well do the crank mains as well. If you have the crank, rods, and pistons out, you might as well hone the cylinders, which means you may have to install oversized pistons, and you will have to resize the rings. This means that when you are finished, you will have rebuilt your entire block.

The N* is not an old school chevy...I've rebuilt tons of them and I can tell you this one is way different. Sal Callizono said in a thread months ago that the design and construction of the N* is unconventional so it stands to reason that you can't use conventional knowledge to repair it...simply meaning that this engine isn't the typical run of the mill V8, another reason to have the factory service manuals on hand.

I'm really pressed for time this morning so I'm unable to go into any kind of real detail at this time, however I've added 4 links to past discussions pertaining to the rebuilding of the bottom end of my engine.

93STS, This is some good information for you to sort through before you start disassembling your engine, particularly if your going to get into the bottom end of the engine. These past threads deal with main and rod bearings, cyl wear, crankshaft, timeserting the bottom end of the block and timing gear setup. All of these posts contain dig pics that I took when I had a problem or needed input.
I hope this helps you :D

http://www.cadillacforums.com/forums/showthread.php?t=31791
http://www.cadillacforums.com/forums/showthread.php?t=24550
http://www.cadillacforums.com/forums/showthread.php?t=24842
http://www.cadillacforums.com/forums/showthread.php?t=26554

zonie77
08-18-05, 11:41 AM
Let me clarify. You can get the engine out without the manual. Do as much as you can while you are waiting. If you get stuck then wait or ask here. I wouldn't pull the bottom end apart anyway. If your engine was running well I wouldn't think about rebuilding it.

If you have bad head gaskets stick with that and possibly the lower block gasket only if it needs that.