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39K views 42 replies 23 participants last post by  96ConcoursJim 
#1 ·
The first step should be obtaining the factory manual and reviewing it to save time and know what you are doing. This is some additional info and is not meant to replace the manual.

Power wash as much of the engine area as possible.

Don't pull the hood or the intake.
Do pull the battery,air intake tube, brake calipers(hang to the inner fenders),radiator(A/C condenser comes out with it),exhaust at rear of engine.wiring harness that goes to the computer(underdash) and end that goes to elect section on drivers side fender,struts at the top,steering shaft to rack coupler(it will seperate when you raise the body),disconnect A/C hoses .
The wheels/tires stay on but with the struts not connected at the top it drops to the ground so block it up near the corners.

Tools) You'll need fuel line disconnect tool, 2 floor jacks, engine hoist to raise body to clear cradle or tall jackstands+wood or something(don't use hollow cement blocks...I had one disintegrate and it didn't get impacted, just shattered!) to give you enough lift to get body to clear cradle,Timesert kit, Metric Allen head sockets(male), special gauge to torque headbolts(Checker/Shucks/Kragen or Azone loan a tool?),1/2in drill, and a factory manual!

Go over the engine replacement section in the manual. It keeps going past the point you stop at because it's replacing the engine, you stop that section and go to pulling the heads.

1) Following the manual disconnect what is necessary to seperate the cradle, keep jackstands under the body. Block the cradle up from the floor (jackstands or wooden blocks to keep it from going to the floor), remove the 6 attaching bolts, raise the body.
Using a jack in front and a jack in the rear manuver the cradle out from under the body. We used a 4X4 under the radiator support with a tow strap wrapped around them. eehoepp made a metal bar with chains on the end and lfted from the strut towers but that means pulling off and realigning the hood

2) you now block up the cradle to work on. Remove the wiring harness as necessary, various brackets, intake manifold etc. I use cheap plastic dishpans to store the parts. That way you can keep the parts for each side/section seperate. They are easy to see and the dishpans keep the dirt and grease contained. Get about 6 (maybe at a dollar store,I got mine on sale for $1 each).

3) The timesert kit comes with simple instructions and is easy to use. There is a locating pin for the hole you are inserting, bolt down the plate and remove the locator pin. Drill out the old threads, tap the new threads(we used ATF as a cutting oil,just need a little), clean out the threads with brake clean or carb cleaner. Make sure you have ALL the oil out. Turn in the insert with just a small amount of loctite on the bottom threads. We used 3 small drops.
We used strips of rags rolled up and pushed into the coolant passages to keep chips out. We taped the timing chain openings.
We got a technique using a good shop vac to virtually eliminate chips flying. One person does the drilling, the other keeps the vacuum nozzle next to the drill and tap. This worked really well but you have to carefully work together. We also rigged a tip with a piece of plastic tubing to get to the bottom of the hole.

Here's an article with some pics. He says it was a waste...Wrong...we had 6 stripped and those were obvious,more may have been damaged. He is also doing a very new engine.

http://caddyinfo.netgetgoing.com/howto/nsrepair.htm
 
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#2 ·
This is additional info from Lawrence.

In addition to Zonie's list you'll need a 4" three jaw puller for the crank pulley, a pulley puller for the water pump pulley (I got one at Harbour freight for $10.00), a 12mmX85mm (correct me here if I'm wrong) bolt to re-install the crank pulley, the allen socket Zonie mentions is a 10mm hex bit drive, you'll need alot of long 3/8 drive extensions and/or wooble extensions for getting the exhaust bolts when removing/installing the engine, and if you don't already have one make sure you get a good telescoping magnet (invaluble for the torque converter bolts). Also if you buy a used Timesert kit, make sure you have Loctite 266 and cutting oil on hand for the job. Don't use anything else. Also have some high quailty harness tape on hand as you will likely need to repair/redo the wiring harness.

The Northstar is as easy as any engine I have ever worked on and so is the Timesert process, as Zonie said. The valve timing is about idiot proof, no problems there. Just line up the timing marks on the crank and intermediate sprockets, install the inner (left chain ?) first by lining up cam sprocket timing marks 90 degrees (straight up) to the head (valve cover) surface. On the exaust cam make sure the "E" is up, on the intake cam the "I" is up. Either way the camshaft to camshaft sprocket "locating pin" is up. Make sure all marks are lined up with the chains tight. Thats all there is to it.

Do use OEM head gaskets, about $45 ea which includes the head bolts. Make sure the gasket and mating surfaces are clean and dry of oil before/while installing. As a personal addition I used RTV around the bottom of the head bolt washer. The top of it is factory sealed. I noted oil down the head bolts when I removed them.

Also as George recommened to me, plan on replacing the HVAC cover while the engine is out. It deteriorates from the rear exaust manifold. I also had to do the inner metal box as well. And while there clean/service the AC evaporator. They get plugged up and can't be done with the engine in the car.

I personally would recommend all new lower oil seals as well. That one got me and I had to pull the engine again. Don't worry much about the valve cover seals, or any other seals that can be replaced later with the engine in the car unless they are obviously bad. On mine I had to replace the intake manifold gaskets as they were shrunken and dried out. At least the ones that contact the head.

One other thing. To be safe, prime the oil system before starting the engine. Do this by pulling the smaller of the two connectors on the drivers side of the coil pack. This cuts power to the ignition. Make sure the battery is fully charged. Crank the motor for two or three 60 second sessions. Reconnect the plug, start the engine and watch the DIC for a low oil pressure warning.

Good Luck
 
#6 ·
97BlueDeville said:
I'm about done with my Northstar Head Gasket Replace / Timesert job. I too would rather put my finger in a meat grinder...

Clint
Careful now. They may wind up in someone's Wendy's chili and then there will be a lot of explaining to do.

I hope I never have to do the headgaskets on my '01 DTS. Frankly, if they were to go bad I'd push it to the end of the driveway and put a FOR SALE sign on it.

Jim
 
#8 ·
Is it really that hard to do????....I dont understand why you would do all that take repair the gasket. Why cant you just take the manifold off and repair it with the engine inside the car still :confused: . I'm not a mechanic so please let me know why you have to do all of this.
 
#9 ·
The head gasket is under the cylinder head, not the manifold. The front could easily be done in the car. The rear could be done with great difficulty (Bbob did it once) but overall it is easier to drop the cradle and do it outside of the car.
 
#11 ·
caddydaddy said:
After all the hard work you put into it, you'd give up like that! I'd keep the thing forever! Get your moneys worth out of it!
Yeah, I'll probably keep it forever. Just couldn't stomach another big project right now. Maybe in a month or two ;).

The car runs fine, though. Almost to the 1,000 mile mark since the reconstruction. I would think if there was a major problem it would've made itself known by now. I do still smell antifreeze under the hood but I can't see it. The level isn't going down so it must be a very small leak.

Jim
 
#12 ·
turbojimmy said:
Yeah, I'll probably keep it forever. Just couldn't stomach another big project right now. Maybe in a month or two ;).

The car runs fine, though. Almost to the 1,000 mile mark since the reconstruction. I would think if there was a major problem it would've made itself known by now. I do still smell antifreeze under the hood but I can't see it. The level isn't going down so it must be a very small leak.

Jim
Heater core or the surge line?
 
#13 ·
slk230mb said:
Heater core or the surge line?
It's not the heater core. If I switch the HVAC to recirc it goes away. The HVAC system is drawing the smell from under the hood. It might be the surge line (you mean the tube to the overflow tank, right?). It was leaking before but I thought I fixed it.

Jim
 
#16 ·
Dam, I really hope my dhs doesnt blow a head gasket. Is there any way to prevent it? Is it just me or do sevilles have more head gasket problems then devilles? Also I had a coolant leak, so the machanic put in the pellets, but there is way too much coolant int the system, he told me to leave it like that, is he right? Can it cause a blown gasket if theres too much pressure in the cooling system?
 
#17 ·
the body of your car doesnt matter,its the n* engine.they say if u change your coolant every 2 yrs. u should be ok.and add the gm pellets. it seems they could make a stronger gasket.thats a couple of thousands or more $$$ repair for a $25.00 head gasket. i just done mine,and everything else i could do while the engine was out.hell to change the oil pan gasket i hear is about $2000.00. now that my engine is out i can see why
 
#18 ·
2000 just for one gasket? :( I feel like I'm going to throw up, I'm paying 700 a month and this car is now off the warranty. I really don't want to get rid of it, so should I try to take out an extended warranty? How does that work? Do they inspect your car before they let you buy the warranty? I'm really not looking forward to a gasket failure. Would you say it's just a matter of time before it goes?
 
#19 ·
Is there any positive feedback on those head gasket cures in a bottle. that stuff only cost like 150 compared to replacing the gasket all together which would cost me over 1500. i would like to install a new gasket myself but i think i would need physical help, ive only worked on my 87 5.0 mustang and that is way different then the northstar engine. I wish there was a video i can buy so i can just do it myself, i have a little time.
 
#20 ·
youngvic812 said:
Is there any positive feedback on those head gasket cures in a bottle. that stuff only cost like 150 compared to replacing the gasket all together which would cost me over 1500. i would like to install a new gasket myself but i think i would need physical help, ive only worked on my 87 5.0 mustang and that is way different then the northstar engine. I wish there was a video i can buy so i can just do it myself, i have a little time.

Nothing out of any bottle of snake oil will cure a failed gasket on your northstar engine or any other. All the information that you will need to know is on this website (use the search features). You will also need the factory manuals for your year car...not Chilton's or Hayne's. You can find them on Ebay or Helms website. Good luck.
 
#22 ·
zonie77

I'm about start this repair on a project car I picked up (finally) which already had blown gaskets. (Milky oil) I got the car very cheap.

Any thoughts on replacing timing chains & cam sprokets ? or other hard parts.
I understand new seals all round is a good idea, from what I've read here.
Car history not well known but has a new factory tranny.
It's a 94 with aprox. 124,000 miles

I am trying something different regarding the headbolts, after time-serting I plan on using ARP head studs. I put a post about the studs in the Tech Tips thread with part #'s.

Thx in advance.
 
#23 ·
The timing chains and tensioners should be lifetime. They may show some wear grooves but if there's nylon on the guide they're good.

Many of the gaskets are rubber and "lifetime". We changed most of them as they are pretty hard at 10+ yrs and why chance leaks. As you disassemble it inspect them and decide which should be replaced.

If the threads in the block are bad you have to timesert to repair them. If they look good then studs should work.
 
#24 ·
N* Head Gasket repair without engine removal

I'm just about finished doing the head gasket job on my son's '97 SLS, without removing the engine. It has been one of the most nightmarishly difficult repairs I've ever done.

We had no room to drop the powertrain cradle because the car had to be rolled in and out of the garage during the course of the many days working on it. Just writing this to affirm that it can be done. There are many tricks that need to be employed to pull it off.

* We Timeserted all 20 head bolt holes. This had to be done since at least 40% of the bolt threads were bad. The drilling for the rear Timeserts is done using a 3/8 drive air ratchet to spin the drill in the cramped space.

* The engine must be rocked forward to get enough clearance to do the rear head.

* You need slender arms and dextrous fingers to get into some tight spots and be able to work by 'feel'.

* Releasing the timing chain tensioners and holding them in the retracted position for reassembly is tricky. It can be done with some clever placement of a long thin welding rod wire.

* Since there will be no access to the internals of the engine behind the front cover, special care must be taken to insure proper cam timing and making sure the crank position stays with cyl #1 at TDC. Make some external timing marks on the crank pully and front cover.

* Its probably a good idea to change out the back HO2 sensor while the head is off and you have access.

* Don't drop anything inside the engine while working on it or you will be removing the engine after all.

* It is not a job for newbies or those with little experience.

* Be sure there is no one nearby who may be sensitive to hearing a lot of swearing :rant2:.
 
G
#26 ·
Geraldius,

I am also in the process of finishing up the timesert process on my 1995 STS.

I did drop the cradle and was able to do all the work with easy access to all
the parts. Even with the cradle out it was still hard to get to some parts.

I can't imagine the headaches that you ran into trying to timesert the heads
in the car. It's nice that you took the time to let people know that it can
be done and to let them know about the tricks that you used.
 
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