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Discussion Starter #1
So I have a 98 cadillac sls, now showing small signs of blown gasket(s). I need advise to tip the motor forward to access the rear head, due to me not having enough room to either pull the motor from top (which I have seen done) OR pull the whole cradle from the bottom. I'm not gonna get rid of it or have someone else do it. I'm the 4th owner with 102xxx on the dash. I suppose anything helps.
 

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It takes a very healthy dose of persistence to take the engine out the top. I know. I have just done it. It sounds like you want to do the repair in the car. That would rule out using Northstar Performance Sure Grip studs. Inserts would be indicated therefore.

Very difficult what with having to lean over the car and do all sorts of wrenching and drilling and tapping, etc. Get a large bottle of your favourite pain medicine and hope it keeps your back muscles from killing you.

Access for the stuff between the engine and firewall is tough. I got just enough access by taking the valve cover off first. But I didn’t move the engine at that time.
I discovered during reassembly of those components that a person could tilt the engine up and forward by loosening the front and driver’s side engine to frame mounts, taking the nuts right off the right side mount, and jacking up the engine/trans unit from under the oil pan. The exhaust down pipe needs to be off to allow it to move freely, as well as both front dog bones. This gives enough room to get the heater pipe supports off, as well as the engine to trans brace.

I think that getting the right/rear exhaust manifold off with the engine in the car would be next to impossible. Since I never tried it, I can’t comment any further on that.

I hope it goes well for you. It’s great that you are keeping another Cadillac alive!

Bjc789
 

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Discussion Starter #3
I really appreciate it! I'm not trying to tackle it anytime soon honestly, I'm still kinda taking it in that I blew it. I'm just trying to sit and get a game plan ready before anything. The car is in to beautiful of condition to just let sit or part out so of course I have to keep it alive! Cadillacs run in blood!
 

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My first two questions to you are:
How old are you, and what are your engine rebuilding skills.
Younger guys may want to tackle this job in the car, but not old farts like myself.
Setting the cam timing in the car is not easy
BJC is being kind by saying it takes persistence to pull the motor out the top.
Dropping it out the bottom is the only way I've done it, and I think I've got one more to do before giving it up.
 

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Discussion Starter #5
I'm 24 but I don't see why that matters? Iv done alot to motors, would I consider it being rebuilt? Probably not no. First time pulling the motor or what I'm trying to do which is tipping it forward yes. but I do want to tackle this myself. I have the factory service manual and I'm dead set and ready to go. Oh and I have messed with timing before so that isnt my going to be any different.
 

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EVERYTHING about Cadillac and the Northstar is DIFFERENT!

We just want you to understand what you are contemplating and whether it is a reasonable undertaking for you.

Have you read up on all it takes to install inserts? No small matter in itself with the engine OUT. Then there’s an almost endless list of ‘everything else’ to know about and contend with. It is good that you want to have a solid game plan in place ahead of time. That will take a lot of reading.

If you approach this with nonchalance or overconfidence it will go poorly.

By the way, YOU didn’t blow the engine, it just happened because they are pre-disposed to fail in this way.

I hope you are as competent as you state. It will take everything you have to pull this off successfully.

All the best.

Bjc789
 

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Discussion Starter #7
When I said I blew it I was talking about the gasket(s) not the entire motor. This is what iv done thus far. Iv replaced tensioner and belt, the engine cooling temperature sensor along with the the pig tail. Replaced the reservoir and all the hoses, the water pump and water pump housing to replace the seals. Checked my fans they are working just fine. nothing is leaking outside but everytime I got something new added to it I always drained and flushed it.
 

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-Administrator- 2002.5 F55 STS 2014 FWD Explorer
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You've probably never been into a timing setup with 4 cams, 6 sprockets, and 3 chains. Follow that GM/Cadillac/Helm service manual to the letter.

What "small signs" - please list exactly what's happening - of a bad head gasket (due to failing cylinder block head bolt hole threads) ?

Purge line and hollow bolt/nipple clear and flowing a steady stream at idle ?

This is a 2000 and later water crossover and parts - but close to your 1998.

Water crossover assembled.gif
 

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I'm 24 but I don't see why that matters?
You will understand in about 40 - 45 years. What Harry was getting at, is it takes us old guys longer to straighten back up after bending over the engine than it did for us to do the job. The "golden years" suck!
 

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Master of the Dark Art of Diagnostics
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BEFORE you start ripping stuff apart -
check the PURGE LINE for constant coolant flow -
AND - after a rigorous test drive - do a BLOCK TEST -

MANY Northstar motors have been falsely diagnosed with failed head gaskets -
when the ONLY problem was a clogged PURGE LINE -
 

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Discussion Starter #12
I definitely checked the purge line before I started replacing everything. I'm sorry I work the graveyard shift, didnt mean tonsound like a ass haha. I totally understand what all of yall are saying. I did the block test and it in fact did turn that yellowish tint. I dont wanna make it seem like I'm not doing my research when I am and dont always want to sit and write everything down. But as I stated before I do have the factory service manuals 1-3 and went through their list of checking stuff off and still having the same issue
 

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OK - thanks for the feedback. The yellow tint in the block tester fluid is NOT good news .........

Some DIY owners have removed the fans and radiator and installed all-thread bars, nuts, washers to replace the engine cradle bolts and used that setup to slightly lower/tilt the engine. Metric thread.
 

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Discussion Starter #14
Its would be nice to see something like that done in pictures. If I have to drop the cradle I have to drop the cradle. I guess I'm at that point now.
 

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Master of the Dark Art of Diagnostics
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Its would be nice to see something like that done in pictures. If I have to drop the cradle I have to drop the cradle. I guess I'm at that point now.
=====================
dropping the cradle SOUNDS like a LOT of extra work and a real pan in the a$$ -
BUT - the end result WILL be worth it - AND you'll actually FINISH the job faster -
 

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I did it successfully on a 96 SLS installing Studs.

  • Remove engine accessories, covers etc
  • jack car up (1st pair of jack stands)
  • Disconnect dogbones, exhaust and steering.
  • Remove radiator
  • loosen, remove side mounts
  • Disconnect rear engine mount
  • Loosen rear cradle mounts,
  • Remove front cradle bolts (yes, 2nd pair of jack stands) and lower front of cradle a bit
  • With properly placed 2x4, jack rear end of motor up an inch or two
  • install more permanent 2x4 straight to ground to hold rear engine up
The above enabled me to get a right angle drill into the area to drill of the rear head area. It also provided enough room to coffee the head onto the studs.

Next time, would probably go with threaded inserts. That would reduce the amount of clearing space needed , although some would be needed to get a right angle drill in.
 

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I did it successfully on a 96 SLS installing Studs.

  • Remove engine accessories, covers etc
  • jack car up (1st pair of jack stands)
  • Disconnect dogbones, exhaust and steering.
  • Remove radiator
  • loosen, remove side mounts
  • Disconnect rear engine mount
  • Loosen rear cradle mounts,
  • Remove front cradle bolts (yes, 2nd pair of jack stands) and lower front of cradle a bit
  • With properly placed 2x4, jack rear end of motor up an inch or two
  • install more permanent 2x4 straight to ground to hold rear engine up
The above enabled me to get a right angle drill into the area to drill of the rear head area. It also provided enough room to coffee the head onto the studs.

Next time, would probably go with threaded inserts. That would reduce the amount of clearing space needed , although some would be needed to get a right angle drill in.
I definitely checked the purge line before I started replacing everything. I'm sorry I work the graveyard shift, didnt mean tonsound like a ass haha. I totally understand what all of yall are saying. I did the block test and it in fact did turn that yellowish tint. I dont wanna make it seem like I'm not doing my research when I am and dont always want to sit and write everything down. But as I stated before I do have the factory service manuals 1-3 and went through their list of checking stuff off and still having the same issue

FYI
I also have a 98 SLS Northstar. I am not letting my Cadi go either. I bought it used in 2008. I think my engine may have been rebuilt before they sold it to me, thankfully. I never had overheating issues until this year. It did not overheat because of gaskets/stud issues. I diagnosed and replaced something every time it overheated. Every car will need some part replaced as the car ages. My overheat issue continued. And every time I worried that the problem was with the headgaskets/ studs. I WAS WRONG. The last thing I replaced was the Coolant Temperature Sensor. The car has not overheated since replacing the sensor

Lesson: all of the Northstars are not going to have the gasket/stud problems. These engines were designed to last long with regular maintenance and care. The car runs like I just drove it out of the factory. Overheating is the only issue I have ever experienced. My 98' has almost all the technology of new cars. Did you know the Northstar has built in ODB scan codes that can be read from the dashboard display without the need of a scan tool?
Photo attached. I think this model should be a classic.
FYI
 

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Discussion Starter #18
Iv done checked/replaced a bunch of stuff coolant wise on the car and and the last time I figured I'd have a look under the intake manifold and there was a nest of some sort under it next to the starter. I put everything back together and now I'm getting that terrible white smoke out of my exhaust. Probably not completely blown but probably has a small crack in the gaskets or something but before I did that there wasnt any smoke.
 
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