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1983 Cadillac Seville
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7 Posts
Discussion Starter #1
My Cadillac (83 Seville 4.1) has a blown head gasket (passenger side), so naturally I am changing both.

I don't have the money to fix it, and was going to finally bid it goodbye. My friend's dad (who restores cars for a living) said he'd help out.. I just needed to get some info.

1) I've heard both ways as far as bolts go. Do I need to replace the bolts? I understand they get pretty messed up when removed. I guess it's better safe than sorry the small price they cost.

2) What are the torque settings for the heads and intake manifolds. I can't find it online.



Thanks for your help!
 

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'85 Fleetwood FWD
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728 Posts
Don't want to scare you, but you need a factory manual (ebay is a good source) if you get into that engine. The cylinder liners are sealed at the bottom of the block, and the water jacket area is open on top, and there is a fixture that holds them in place with the heads off, so that they don't get un-sealed etc. The bolts in the aluminum block may be a problem with threads coming out. There is mention on another post about thread inserts, called time-certs, which can be found online with a search, in case you need some to repair a bad thread in the block. Haven't heard about replacing the bolts.
 

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Super Moderator
2010 DTS
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87,547 Posts
When I replaced the head gaskets on my 4.1 many moons ago I DID have a FSM but was unaware of the holding fixture so obviously I did not use it and had not problems. I DID reuse the bolts. There where a few things as I recall that I would not have known or done with out a FSM. I'd strongly recommend one. I also recall some very brittle clips or such on the rocker arm shaft. If you start at one end and start removing the bolts, they will snap. I had to replace several. I was much more careful on installation. I worked my way down one turn at a time and then started over so as to slowly tighten it down evenly.
 

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'87 SDV
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1,296 Posts
You're going to get varied opinions on the wisdom of this project. Back in the day, Cadillac recommended against replacing the head gaskets, they just replaced the engine (a LOT of them). If the car is in great shape, it's worth a try, but be prepared to accept failure if things go wrong. Here's some of what you're up against:

1) The old HGs may have been leaking internally for some time, allowing coolant contamination of the oil. This could have caused flattening of cam lobes, scoring of cylinder walls, and excessive crank bearing wear.

2) Cracking open a mixed metal engine always presents a risk of warping the block once the stabilizing pressure of the head bolts is released. If that happens, serious machining is required to get a seal. Problem is, you won't be able to tell if it warps until you've finished the job.

3) The cylinder head bolts must be torqued exactly to spec, twice (38 and then 68 ft lbs respectively), and in exactly the correct order, or you WILL strip a bolt hole. Here's the sequence from my '87 DeVille manual, yours may be slightly different:



The intake manifold is a bit more complicated (16 bolts in 4 different lengths), and you'll need the Factory Service Manual for the proper torque sequence. You should not need to replace the head bolts - that's only required on Northstars - but it's not a bad idea to do it anyway.

Go into it with your eyes open. It's a time consuming job, and your chance of success/failure is probably 70/30 with the help of a good mechanic. In your shoes, I probably would think about a reman engine or just kissing it goodbye and finding another car.
 

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Registered
1983 Cadillac Seville
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7 Posts
Discussion Starter #5
Don't want to scare you, but you need a factory manual (ebay is a good source) if you get into that engine. The cylinder liners are sealed at the bottom of the block, and the water jacket area is open on top, and there is a fixture that holds them in place with the heads off, so that they don't get un-sealed etc. The bolts in the aluminum block may be a problem with threads coming out. There is mention on another post about thread inserts, called time-certs, which can be found online with a search, in case you need some to repair a bad thread in the block. Haven't heard about replacing the bolts.
Thanks! Can you link me to these time-certs? I'll do my best to look into them as well.
 

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1983 Cadillac Seville
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7 Posts
Discussion Starter #6
When I replaced the head gaskets on my 4.1 many moons ago I DID have a FSM but was unaware of the holding fixture so obviously I did not use it and had not problems. I DID reuse the bolts. There where a few things as I recall that I would not have known or done with out a FSM. I'd strongly recommend one. I also recall some very brittle clips or such on the rocker arm shaft. If you start at one end and start removing the bolts, they will snap. I had to replace several. I was much more careful on installation. I worked my way down one turn at a time and then started over so as to slowly tighten it down evenly.

Call me ignorant, but what's an FSM? (I'm horrible with abbreviations, lol). Thanks for the tips!
 

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Registered
1983 Cadillac Seville
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7 Posts
Discussion Starter #7
You're going to get varied opinions on the wisdom of this project. Back in the day, Cadillac recommended against replacing the head gaskets, they just replaced the engine (a LOT of them). If the car is in great shape, it's worth a try, but be prepared to accept failure if things go wrong. Here's some of what you're up against:

1) The old HGs may have been leaking internally for some time, allowing coolant contamination of the oil. This could have caused flattening of cam lobes, scoring of cylinder walls, and excessive crank bearing wear.

2) Cracking open a mixed metal engine always presents a risk of warping the block once the stabilizing pressure of the head bolts is released. If that happens, serious machining is required to get a seal. Problem is, you won't be able to tell if it warps until you've finished the job.

3) The cylinder head bolts must be torqued exactly to spec, twice (38 and then 68 ft lbs respectively), and in exactly the correct order, or you WILL strip a bolt hole. Here's the sequence from my '87 DeVille manual, yours may be slightly different:



The intake manifold is a bit more complicated (16 bolts in 4 different lengths), and you'll need the Factory Service Manual for the proper torque sequence. You should not need to replace the head bolts - that's only required on Northstars - but it's not a bad idea to do it anyway.

Go into it with your eyes open. It's a time consuming job, and your chance of success/failure is probably 70/30 with the help of a good mechanic. In your shoes, I probably would think about a reman engine or just kissing it goodbye and finding another car.

Thanks a lot!

For the last month the car was running on water/coolant and the last two weeks on water... I'm sure it did it no good, but my mechanic said since the damage seems minimal (very little white smoke, almost no bubbles, and the car doesn't overheat) that there's a chance the oil wasn't contaminated. We did check the oil and it didn't show any signs... I hope all is good. :)

As for the torque settings, are these the mentioned settings for the Ht4100? Also, where can I find a manual fast? The only place near me can only get me a manual after next Saturday and that's the only day that I can get my friend in to help out.

I hate time rushes and limited funds... but I want this done right.
 

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1983 CADILLAC COUPE DEVILLE
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5 Posts
FACTORY SERVICE MANUAL, Sounds like a pain in the @%!!, i would opt for reman motor if you have the money to do so!
 

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1983 Cadillac Seville
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7 Posts
Discussion Starter #9
Thanks, but I don't have the $$ for a new motor. My friend who's helping me has done this several times, not with this engine, but other PITAs out there.
 
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