My turn to do the at home Northstar headgasket repair - with a twist!

[ejguillot]

Well, I bought this 2000 STS three years ago, with 91,250 miles. Now at 140,400 miles, I have conclusive proof that the headgaskets are failing. Most everything else in the cooling system has been replaced in the last 2 years:

Radiator (cracked side tanks)
Water pump (Leaking through shaft and seal)
Coolant crossover gaskets
Thermostat (got stuck open)
Radiator cap (plastic piece broke, wouldn't hold pressure. This was installed last month.)
Main radiator hoses (This was a precaution. Old ones looked fine).

And now I'm getting coolant bring forced past the radiator cap. The final piece of evidence: I take the radiator cap off after an overnight cool down, put my nose to the radiator cap, take a deep breath, and smell coolant... and engine exhaust.

Spoke to Jake at Northstar Performance, and he agreed: It's the headgaskets.

Here's the twist: My 4T80E transmission is flaking out too! 2 problems for the price of 1! Symptoms there are:

Fluid has gone from bright red (complete fluid change at 102,000 miles, not a flush. Did it the old fashioned way, and to get the rest of the old fluid out detached a trans cooler line and pumped out the old fluid while adding new until new fluid came out) to red/brown in 39,000 miles.
Increasingly hesitant to engage torque converter lockup, takes longer to engage than usual.
Twice in one week, missed the 1st to 2nd shift at WOT (normal shift at 6400, engine bounced off the rev limiter at 6500-6600 2-3 times before shift was completed, with an abrupt bang. No more WOT shifts until this is fixed.

[jubjub]

hello I pull these engines out the top all day long. I work as a tech for a cadillac dealer and yes its easier to drop it out but i dont have a lift at home. once the motor is out put it on a stand and go to work. with the motor out the trans can be snatched out. check your driver side axle seal at the channel plate. these 4t80 will leak out of that seal and its a sure sighn of a worn 3rd clutch housing faliure in the trans. this will cause all kinds of wierd trans problems

[Pete315]

how much more easier is it to remove engine from bottom? since you pull them out from the top all the time, what is the hardest part? any tips? I'm thinking of pulling it out the top also. steps (not all of course) listed would be great.

[Ranger]

Yeah, if you have a procedure for pulling them from the top, a write up in the Tech Tips section would be nice.

[cooncat]

So Edwin,
Have you decided to keep the Caddy then and fix her. I do love her and she is beautiful. I have always loved that body style.
Keep me posted.

[Krashed989]

I pulled 1 from the top, but it was so long ago I don't think I would be able to make a decent write up. After that I dropped the cradle every time. Pulling it from the top was about 20x harder than from the bottom. Simply put, it's not made to be taken out the top. You'll find that none of the bolts are pointed in the right direction. Unbolting the exhaust Y pipe was one of the hardest parts (I had to actually lower the cradle to get to the bolts).... One of the benefits of pulling it from the top though, is that you can leave the A/C virtually untouched.

[ejguillot]

So Edwin,
Have you decided to keep the Caddy then and fix her. I do love her and she is beautiful. I have always loved that body style.
Keep me posted.

In this case, it's cheaper to keep her.

Have to go talk to my credit union, as there's a chance I can get a loan to pay for the repairs. The loan amount would be added to to my current car loan at my current interest rate, so I would just have to make 7-9 more payments, depending on loan amount. Best way I can find to pay for this, since I don't have the cash on hand.)

Does anybody who has done this have a list of the other parts/gaskets they bought?

For the transmission repair, I have to buy:

Replacement Trans ($350-400 + tax locally)
New torque converter clutch solenoid
Dexron-VI fluid

For the Headgaskets:
SG102 stud kit from Northstar Performance ($549)
Gasket kit (Jake told me that Fel-Pro has a kit with all the top end gaskets I'll need. Looking for a part #)

Might do the half case seal too, so:
Bottom half gasket kit (I think Fel-Pro makes a set too)

For the removal/reinstall of the cradle, I do plan to drain the A/C freon, so:
Rent vaccum pump from Autozone
Rent A/C manifold gauge set from Autozone
2lbs of R-134 Freon
Don't think I'll need new PAG oil
New orifice tube (might as well inspect the one I have and see how the compressor's doing)

Other items I'll need:
Dex-Cool coolant
5W-30 oil and filter

Tools I have to buy/rent:
Engine hoist (prefer to rent)
1/2" torque wrench (I currently have a 3/8" torque wrench, 75 lb ft max) from Sears: $30 (buy)

All, feel free to add on to this list!

[ponyboyt]

not sure how much different a 2000 is from my 97 but...

I didnt have to touch my A/C. (i did touch it, but figured out after i coulda left it). Can just unbolt the compressor and prop it.

Inch pound torque wrench.

Borrow a pump truck from someone, nice to have to move the entire cradle around.

Take a GOOD look at your ABS pump and brake lines before you start. You can do the pull and only remove 2 lines, and prop the pump up somewhere in the body, unless some of them are in rough shape at which point they will probably break. I got lucky and only lost my front drivers side line, the shortest line on the car

Don't be afraid to raise and lower the car a few times with the cradle held in place so you can get at some tough areas. I lifted mine probably more than 10 times jsut to get at the exhaust and some hard to find plugs. M engine compartment was very dirty and greasy, making it hard to spot some wires and connectors.

Good luck! And have fun with it, it can get frustrating but when the solution pops up it feels great.

Edit:

I've seen this argument lots of times. Pull it from the top or bottom? This is my conclusion:

People have found a way to get it out the top, but each person probably has their own ways of getting at certain things. We can say its been designed to to come out te bottom, and there are detailed instrucions on how to do it. Every nut and bolt that has to come off can be gotten to with a socket and ratchet. Some times it looks like you can't get one in there but i promiss you, you CAN. There are little gaps and holes everywhere to do so. Once the cradle is out just standing there looking at it, you can SEE how easy it is to work on everything. Taking it out the top, i can see the need for a lot of wrenching and scraped knuckles. Take my conclusion with a grain of salt, i've only done this once But thats just my 2 cents.

[cooncat]

I am happy you decided to keep her. I hope that after all this, you should be okay for a long time. As I said before, she is a beautiful girl. I hope to see you at more of the Caddy events.

[Krashed989]

...Take a GOOD look at your ABS pump and brake lines before you start. You can do the pull and only remove 2 lines, and prop the pump up somewhere in the body, unless some of them are in rough shape at which point they will probably break. I got lucky and only lost my front drivers side line, the shortest line on the car ...

On both my 94 and my dads 99 I never had to mess with the brake lines. On the 99 there is a line running on top of the front of the cradle that I had to unclip from the cradle, but all of the brakes stayed intact and with the car while the cradle came out. I was able to leave the A/C intact on my dads 99 as the cradle came out, but it started leaking freon so I can't say it was untouched.


Another major issue on removing the engine from the top is the wiring harness. You have to unplug pretty much everything which is a pain (literally and figuratively) when the engine is in the car.

[zonie77]

here's something that will answer a lot of your questions:

http://www.cadillacforums.com/forums...ir-part-i.html

http://www.cadillacforums.com/forums...et-repair.html

[zonie77]

If you pull it out the top you need an engine hoist. If you drop the cradle you need an engine hoist...not a lift. You are lifting the body (which is surprisingly light) off the cradle.


You do not have to remove any brake lines. Cover the ABS module so it doesn't get wet.

I disconnect the AC because I can easily recharge. Some people say you can leave it in.


Harbor Freight has/had an engine hoist for $99.99 recently. Resell it on Craigslist.

People think dropping the cradle is soooooooooooooo hard. It isn't!!! If you are only planning to do this once, dropping the cradle is the easiest way.

[ejguillot]

I do plan on dropping the cradle. Car is still driveable if I stay out of the gas, so I'm lining up all the parts so I can have most everything I'll need before getting started.

If all you're doing is disconnecting the A/C lines from the compressor, do you still need to replace the PAG oil?

[zonie77]

If all you're doing is disconnecting the A/C lines from the compressor, do you still need to replace the PAG oil?

No, cover or plug the open lines to keep moisture and dirt from accumulating in the system.

[chubbyranger]

Might do the half case seal too, so:
Bottom half gasket kit (I think Fel-Pro makes a set too)

Current GM procedure is to use liquid gasket sealer. When I had mne done they found a set of regular gaskets, I think the set was ~$350.