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1999 Cadillac SLS
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72 Posts
Discussion Starter · #1 ·
Ok. As most of you know, I just bought a 99 STS. Well, after being in the shop for a few weeks, the guys figured that it's a blown headgasket causing the overheating and they quoted us 6000 bucks to fix that. So, bump that, I'm taking matters into my own hands. The Northstar can't be that much harder then the 5.0 I took apart and put back together.

Anyways, are there any DIY write ups to fixing a blown headgasket? I do have the ability to lift the engine and all that. We have a lot of tools. Also, can someone please direct me to a good site where I can get all I'll need to fix it?

And what are common symptoms for a blown headgasket besides overheating? I don't trust these guys, I want to make sure.
 

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90 Eldo -SOLD-, 98 ETC -SOLD-, 86 XR4Ti Track Car, 07 Ranger
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clogged coolant system, damaged or broke thermostat, toasted waterpump, loss of coolant all of these can cause overheating but if you're constantly filling your coolant with no puddle under the engine, it has to go somewhere and it's almost definitely going into the cylinders. Now what they said is a blown head gasket is almost definitely not your case because if you had a blown headgasket you'd have no compression on one or more cylinders and the car would run like $hit. Instead you may have pulled headbolts which means a lifted head, where there's just not enough clamping force to keep the head on solidly and thus allows some small amount of coolant to enter the combustion chambers. This is what happened to me and it took literally 1 full year of hard driving to finally 'pop' the head up far enough so that I blew white smoke (i.e. alot of coolant was pouring into my cylinders at that point). A $100 test for hydrocarbons in the coolant system will confirm this, however realize you could also have a cracked block (VERY RARE).

If you've rebuilt a 5.0 (I'm assuming a SOHC iron block feel free to correct) you'll find this a bit more challenging because you have to be a bit more careful w/the aluminum, and the heads are a bit more complex but otherwise it's not rocket science, just buy a FSM, the whole rebuild procedure is there, or get an updated shop rebuild manual on the N*, there are a couple of kits you can use, either the GM approved Timesert kit or Norms NS300L kit. I have Timeserts in my block and 20k miles later they're holding fine, I've heard good things though about Norms kit (on ebay) and it's a helluva lot cheaper than a Timesert kit, if I'd had the time to do the repair myself I would have used Norms kit but hey that's just me.

Goodluck and keep us posted.

Oh if you have tools, Norms kit is $300, and all said if nothing else is damaged you may luck out and be able to do the job for well under $1k :)
 

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2010 DTS
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Whoa. You can certainly can have a blown head gasket and still have good compression.

Symptoms include overheating and/or loss of coolant.

I think there is a "How To" in the Tech Tips section.
 

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1999 Cadillac SLS
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Discussion Starter · #4 ·
Whoa. You can certainly can have a blown head gasket and still have good compression.

Symptoms include overheating and/or loss of coolant.

I think there is a "How To" in the Tech Tips section.
I'm not lossing coolant though. That's what's puzzling me.
 

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2010 DTS
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Notice I said and/OR. Do a cylinder pressure test. That will either positively confirm or rule it out.
 

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Eh, bummer. Just did this repair. Not at all fun, but if you have done major work on cars before, then you will be fine. Mine should start up tomorrow, just got it back in. Took me around two weeks to fix it and alot of that was parts. Search for the headgaket repair, Zonie77 did a guide.
 

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1992 STS / 2005 MB G500 / 2003 STS / 2006 XLR-V
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Whoa. You can certainly can have a blown head gasket and still have good compression.

Symptoms include overheating and/or loss of coolant.

I think there is a "How To" in the Tech Tips section.
Exactly what I was about to type.

A couple of things...

1. The headgasket job is expensive, but 6000.00 is absolute rape with no reacharound. Thats officially the highest number ive ever heard. You should be able to have the timeset kit done for 3000, or buy a new rebuilt motor and have it installed for 4000-4500 or so that includes timeserting and oil leak sealant around the case half (Custom Innovations on Ebay).

2. The "this headgasket cant be that bad" response is quite common to someone who is not familiar with them. Its a FWD engine which means the motor is mounted transversely rather than longitude-wise, so your first problem is its nearly impossible to get to the head on the backside of the motor (just ask JC316 about this one). Which means the next step is you have to entirely drop the front cradle... and so on and so forth. To give you an idea... the book states labor on for a Northstar head as about 18-20 hours.

Not saying it cant be done if you have some mechanical skills, but prepared to invest alot of patience into this project if you decide to do it yourself.
 

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1999 Cadillac SLS
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Discussion Starter · #10 ·
All I need is a quide. My dad and I will get it done in a weekend, as long as we don't break anything.xD
 

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'93 STS (sold), now looking for a CTS Wagon soon!!
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Buy the 2-book service manual. $80 Worth every dollar.

I believe a new GM Northstar with warranty is around $4,500. Give or take your shopping skills?

$6,000 for the repair? A rip-off.

( Take a weekend? - This isn't a small block Chevy )
 

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1996 Cadillac Fleetwood Brougham
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$6000 is too much and out of proportion .I think you'd better get a brand new engine for that price
 

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1997 Polo Green Cadillac Seville STS
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hell dude, one person on eBAy sells remanufactured Northstars for $3000 with shipping paid for a core return... These engine have several known Northstar problems addressed and fixed, such as the timeserts, piston rings, etc.... Swapping a new engine should be worth more than just trying to timesert a higher mile N* engine.....IMHO

Unless you're just looking for a mechanical challenge

Then ok.. good luck to you...:bouncy:
 

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1999 Cadillac SLS
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Discussion Starter · #15 ·
$6000 is too much and out of proportion .I think you'd better get a brand new engine for that price
My mom and I were just thinking about that. Would it be beneficial to just drop in a new engine?

It's a 99 STS, excellent condition with 91k miles on the current engine.
 

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94 STS, 04 Deville
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How much value to the car would a new engine add?
i wouldn't drop in a new engine if you plan on turning around and selling it to get a 540 or another sts because you wont merely make back all the money you just threw in it. If you plan on selling it as you said in the other thread just sell it "as is" as a buyer beware vehicle. But dont give up hope just yet i had the same problem in my sts and i replaced the theromstat and it never over heated again, it was all gooked up and gnarly and it took 30 minutes to replace and was like 25 dollars
 

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2010 DTS
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And how do I do this test?
Pull the plugs. Get or make an adapter from a spark plug. Drop a 16" wooden dowel rod into #1 cylinder so it is touching the piston. 16" may be too long, I am not sure. Just be sure that there is enough sticking out when at BDC so that it is still visible. You can shorten it as needed. Put a wrench on the harmonic balancer bolt and rotate the engine while someone watches the dowel rod. When the dowel reaches its highest point, stop and remove it. Put the adapter in the plug hole and connect shop air to it and pressurize the cylinder. If the air keeps running, then you are on the exhaust stroke. Remove the hose and adapter and rotate the engine again. The piston (and dowel rod) will go down to BDC and then rise again to TDC. This time it will be on the compression stroke. Now reconnect the adapter and air hose and pressurize the cylinder to 125 - 150 psi. Let it set for :15 min. or so while you watch the surge tank (cap removed) for bubbles. Repeat this procedure on all 8 cylinders. If bubbles appear, the head gasket is breached at that cylinder. If no bubbles appear from any cylinder, the head gaskets are good.
 

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that should be a sticky ranger so many discussions have been on how to test for head gaskets and such. nice job man. i might do it this weekend just for kicks lol
 
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