: N* Head Gasket repair



zonie77
02-15-05, 12:17 PM
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

zonie77
02-15-05, 12:19 PM
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

zonie77
03-03-05, 11:16 AM
In the original thread there are a few pictures. I couldn't move the pics here easily so I'm putting the link in case anyone wants to see the rest of the info.

http://www.cadillacforums.com/forums/showthread.php?t=5052

illumina
03-13-05, 01:41 AM
I've done a Northstar head gasket job before. I prefer grinding my fingers in a blender...Good information by the way...

97BlueDeville
03-31-05, 02:05 PM
I'm about done with my Northstar Head Gasket Replace / Timesert job. I too would rather put my finger in a meat grinder...

Clint

turbojimmy
03-31-05, 02:22 PM
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

caddydaddy
03-31-05, 03:47 PM
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!

starfox86
04-05-05, 06:59 PM
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.

zonie77
04-05-05, 11:09 PM
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.

starfox86
04-06-05, 12:58 AM
Ohhhh...got it...sweet .. Thanks a lot!:thumbsup:

turbojimmy
04-06-05, 07:20 AM
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

slk230mb
04-06-05, 12:05 PM
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?

turbojimmy
04-06-05, 04:35 PM
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

slk230mb
04-06-05, 04:48 PM
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

Yea, the line from the overflow tank.

cbellpeanut
05-08-05, 06:49 PM
What All Parts Are Needed To Replace Head Gaskets?do Anyone Think This Is Due To A Bad Egr Valve? I Thought Dex Cool Was Good For 5yrs.#$^(&*

dhs
06-01-05, 12:46 AM
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?

cbellpeanut
06-05-05, 01:18 AM
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

dhs
06-05-05, 02:36 AM
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?

youngvic812
09-03-05, 08:48 AM
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.

white97deville
09-16-05, 08:45 AM
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.

ToolnDie
09-27-05, 10:51 AM
94 Eldorado 87,000 head gasket not an EZ job but well worth it in the end. Replaced everything as needed body mounts engine mounts all gaskets and steel lines O ring's A/C assem. Car run's great now. What ever you think in time to do double it.

JaxxMan
01-12-06, 10:59 PM
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.

zonie77
01-13-06, 01:29 AM
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.

Geraldius
02-12-06, 08:22 PM
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:.

Playdrv4me
02-13-06, 07:07 PM
Geezus what a friggin NIGHTMARE!

ramdge
02-15-06, 02:30 PM
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.

N0DIH
02-16-06, 03:46 PM
So if you found a N* with a blown gasket, what price would you pay for it?

What price on the car would make it worth it?

ramdge
02-17-06, 06:44 PM
I paid $1500 for my 1995 STS. I thought that was a really good deal. It was
still driveable but only for 10-15 miles before it started getting hot.

I think it depends on whether you can fix the car yourself. If you have to
pay to have it fixed your are probably looking at 2000-4000 dollars which
makes it not such a good deal.

If you have the time and money to fix it, I think cost wise it will be
about $1000 or less.

That makes my 1995 a good deal at $2500 total.

A word of warning though is that car problems can always turn out to
be more costly to fix than anticipated because the damage can be more
severe than you thought. For instance, if the timesert process doesn't
fix the block then you will most likely have to buy a complete used
motor.

I'm hoping my repair will fix mine but I won't know until I get it back
in and running.

N0DIH
02-17-06, 08:08 PM
Hmm, wonder if I can fit an LT1 or a 5.3L LS1 into a STS..... They are dirt cheap in comparisson.

JaxxMan
02-19-06, 12:30 PM
I just started this job I need help! I forgot my service manuals at home. (Yes I really own a pair)

1.)I'm stuck around the ABS module, mine seems to be wired directly to the harness. Also it is in the way when I lift the car.

2.)The wiring harness itself in the same area as the ABS. How the heck do you get in there to remove it ?

There has got to be an easier way to remove the harness then what I am doing. My brother thought we could dissconnect it at the firewall but it doesn't look like the connector can come apart there.

Anyone have some tips they can pass along. I really want to get the engine out today.
TIA JaxxMan

onecad
02-19-06, 04:56 PM
If anyone has directions/steps as to what needs to be done to replace headgaskets while the engine is still in the car I would appreciate it, i dont have room to have the chassis and body separated so i would like to consider doing it the "hard" way. I have all the tools ( well most, except to disconnect the fuel line if need be) to do this, just not the space. Thanks
for your reply's. And if you yourself have done this how much time did it take?
-O

zonie77
02-21-06, 12:04 AM
This is the Tech Tips section. It's a FAQ type section. If you want questions answered you ought to be posting in the Northstar section.

Jaxxman...the 94 wiring is a PAIN! You have to disco it at the computer under the dash. It's been a couple of years but the ABS module can stay in the car. I don't remember the details of the wiring though. It seems like we unplugged it. It is not easy to disco the wiring...they changed the wiring and a 96 is much easier.

onecad...the recommendation is do not do it in the car. If you do it you can write up a tips thread on doing it that way. Geraldius just posted he did it, maybe he will see this. He did put a few hints in his post.

JaxxMan
02-21-06, 02:33 PM
I tried to send a PM to thank you Zonie but it said I can't until I have 50 posts. I found what I needed in volume 2 of the Factory manual for the ABS wiring. A lot of good stuff in volume 2 should have spent more time there.

Will be back to my brothers shop tomorrow night to finish getting the motor out. Thx Again. JaxxMan

Geraldius
02-27-06, 12:33 AM
A tool to disconnect the fuel lines can be made quite easily. I used a short length of 3/8" polyethylene tubing with a slit down one side. Open the slit to slip it over the fuel pipe and then slide it into the receptacle on the fuel line to release the locking tabs. Then the fuel line slides right off.

faustfamily
03-14-06, 09:29 AM
I opted to try the mechanic in a bottle. I used the Bar's Leak Head Gasket repair formula in the Silver bottle, (about $9.00). Anyhow, it took five tries as I had to remove the plugs in each leaking cylinder per treatment. All of my leaks where in the 1, 3, 5, and 7 cylinders. This makes sense as those cylinders are in the back and have little airflow for cooling.

The car is a 1996 Deville and it has 163K miles on it. After reading about the cost and difficulty of fixing the head gasket leak, I chose to try the easiest method first. I love the car and I did not want to dispose of it as it still drives and runs great. It is hard to believe that it runs so well with a leak.

Back to my experience with the additive. After five tries it appears to have worked. I have gone 2K miles now without problems. It took over a month as I had to do one cylinder at a time on each weekend, but it was worth it. Each time takes about two days as you have to run the car and then let the engine cool for the next step.

I know there are a lot of individuals out there with similar problems on their Northstar. I just wanted to let other know of my experience with the Bars Leak product and I'd have to say that it has worked for me.

white97deville
10-06-06, 08:13 PM
Here is a pic of my Nstar coming out from under the car. I worked slowly and took breaks but it took 3-5 hours for me to get it out of the car and about the same to put it back in. I had it on the floor of the garage for about 2 months though as I had to work on it as I had time available. An air compressor is an invaluable tool when doing the drilling/tapping for the timeserts to keep all the shavings blown away from your engine and out of the holes you are drilling/tapping.

willbr1
04-20-08, 04:30 AM
Just finished my head gasket repair on my 96 STS with 170,000 miles. Just a few observations that might help others:

Order a Time-sert kit direct from Time-sert. The kit with 20 inserts will cost $450. I only saw one headbolt hole with the thread coming out, but while fastening the jig in place I found 3 more that were definitely stripped. Make your life easier in the long run and Time-sert all 20 whether you think you need to or not. Who would want to do this a second time?

Leave the wiring harness on the engine. Zip tie the fuse boxes that won't disconnect to the motor. The wiring harness will disconnect under the passenger side dash.

As others mentioned, hang the brake calipers on the inner fenders and the anti-lock brake system to the body. This means that you won't need to bleed the brake later.

Once the car was raised to the right height. I lowered the cradle on the engine hoist legs and it rolled right out. This might be easier than backing the car over the engine.

Thanks to all the previous posters for your help. You saved me a lot of time!

willbr1
04-21-08, 05:33 AM
A few more suggestions for Time-serting:
Go down to your local building supply store and get a roll of plastic sheeting. Cut off a piece big enough to cover the whole engine and transmission assembly. Place the Time-sert jig right over the plastic and run the bolts right through. This will keep most of the metal shavings out of the engine.

I prefer using a shop vac instead of compressed air to clean up the metal shavings. I want to remove the shavings rather than blow them elsewhere (like your eyes.) Use safety glasses. To clean the shaving out of the holes, cover the end of the shop vac with your hand slightly and place a plastic straw between your fingers. It will suck all the shavings and brake cleaner right out. I also used this straw technique in the cylinders before re-assembly to get any foreign material out.

Here is a Time-sert video link showing how they do the insert process on an N*.

http://www.timesert.com/html/gm.html

zonie77
04-21-08, 01:35 PM
The sheet of plastic is thinking out of the box!

We used the vac with a small tube attached also. It worked really well.

robshelby
06-18-08, 06:12 PM
Geraldius02-12-06, 07:22 PM
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


i am sooo stuck on the timing chain tensioner that i am ranting like crazy and my caddi has been sitting for a year. I can grab that little sliver of a release but always lose the tension when i try to put the chain on the sprocket. if the car wasn't so damn pretty i would have beat the heck out of it

deebaubles
03-04-10, 02:12 PM
I wish I was as experienced as you all. I wish I had googled replace head gasket on cadillac n* before i decided to fix this.

I have a 97 Deville. Great car, but it started overheating and leaking coolant (about 1/2 gal every 2 days). I have a mechanic I trusted - Had been working on my cars (including this one) for about 7 years. Like i said, I trusted him. Has always done good work cheap. He quoted me $750 (incl parts) and 3 days to change out my head gaskets.

I like the car, so I decided to go forward with the repair. Well, 17 days later (what happened to 3???) he says he is done with it.

He broke numerous other parts pulling the cadi appart. He ended up wanting $1250.

Problem is, car runs like CRAP! It is not overheating or leaking coolant (that I can tell) But while idolling, the car is very loud, runs very rough and feels like it is going to kill at any moment. There is also a pungent aroma while driving - slightly like rotten eggs?

So, googling this problem (which i should have done before agreeing to repair - but i thought he knew what he was doing - he has been a mechanic for at least 20 years) I see this. I have all of the reciepts for this repair and there is not a reciept for a timesert.

Do the above problems sound like a headgasket problem still? Will the car continue to run with new headgaskets but no timesert? He says the rough idol is due to a fuel or vacume problem... but now I dont trust him anymore and dont want him to touch the car - but all the same know I can not afford to put much more money into this thing.

Just looking for ideas of what I might be in for... Now Im paranoid that the car will just blow up and take me and my kid out with it.

Any thoughts/advice are appreciated!!!

Ranger
03-07-10, 11:36 AM
This section is for "TECH TIPS". You won't get an answer here. Repost in the Northstar forum.

96ConcoursJim
04-10-10, 11:11 PM
I am in the final stages of an engine in timesert {BIGSERTS} repair. And boys and girls, you should not attempt this if you have a weak stomach. A lot of hours and pain are involved. Not to mention the lack of room when trying to drill the back ten holes. Tiger would even have a problem with it. I'll post up some pictures when done in the album section soon. But I agree with robshelby, the car is too pretty not to hang in there and finish.