jcobz28 Posted January 28, 2007 Report Share Posted January 28, 2007 Background Bought the car real cheap with a known major coolant issue - assumed the worst (head gasket/bolts). Finished tearing down the motor today... and I was right! I am kind of surprised that only ONE of the bolts pulled out the block threads, and that just one bolt caused all this damage. A few others had little slivers of aluminum in their threads, so maybe they were starting to go as well. I had lots of coolant in 3 cylinders on the rear head. Time to timersert the block and start putting it back together. Mug-shot pics of the offenders: Also, question about what parts I should replace while I got this bastard torn down. From my reading on here, I have gathered that the blower motors are a biotch to get to normally and commonly fail. How can I test this one while it is easily accessible? (white arrow) Also, the black plastic indicated by the red arrow was severely brittle from the heat of the exhaust manifold and cracked into a million pieces as I was dropping the motor. What are people doing to "fix" this? Leave it? Replace it with a new dealer piece? Other aftermarket/DIY solution? What other major things should I replace while everything is apart? Keep in mind I'm trying to flip this car and not spend $ on things that don't need to be replaced... but I want to do common sense stuff. I figure I'll do the water pump, t-stat, maybe O2 sensors, clean EGR... Comments? Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 28, 2007 Report Share Posted January 28, 2007 The blower motor can be removed while the engine is in the car, but you might want to replace the plastic HVAC cover it's about $100 I believe that is what cracked up on yours at the red arrow. Also consider replacing the two heater pipes that wrap around the back of the engine near the firewall, they rust. How is your positive battery cable? This is a good opportunity to replace the cable.. If you have aluminum thread in the bolts they were probably pulled, you were leaking in non contiguous locations so your head gasket was leaking in more than one spot. If you do searches, you will find that a lot of our members have timeserted their engines. Members that I know that timeserted their engines are KHE, Growe3 and jhall among others. Here is a link to jhall's excellent part and cost breakdown: http://caddyinfo.ipbhost.com/index.php?sho...amp;hl=timesert You must replace the head bolts. Its possible that you can buy a timesert kit here or on Ebay but you will need the inserts.. Good Luck with this and post pics and details if you can.. Mike Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted January 28, 2007 Report Share Posted January 28, 2007 Nice pics and thanks for posting. I wish I had the right skills to do this type work. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Poobah Posted January 28, 2007 Report Share Posted January 28, 2007 I'll bet you that coolant got into your cylinders when you broke the head gasket seal. Some of them look like they have enough liquid in them to hydro-lock. Also, when the engine is running the temperatures in there are hot enough to vaporize the coolant. A cause of head gasket failure, that isn't discussed much on this forum, is fire ring fatigue. After the engine has gone through many hundreds of thermocycles (heating up and cooling down), the metal fire rings around the cylinder holes can work-harden and become brittle. All-aluminum engines are hard on head gaskets. Tiny hairline cracks can develop along the metal surface at the edge of the gasket where it's exposed to the heat of combustion. (I know this can happen because the guru did an autopsy on my failed Eldorado head gaskets a few years ago and that's what he found.) Look very carefully at your gaskets and see if the fire rings are cracking (the cracks are very fine and hard to see). The pulling of head bolts very often happens on assembly and disassembly of the engine rather than during operation. While the engine is apart, be sure to check for obvious things like cylinder wall and cam lobe wear and cracking of the heads especially around the exhaust valve seats where they get the hottest. Good luck with your project! Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
Ranger Posted January 28, 2007 Report Share Posted January 28, 2007 I'll bet you that coolant got into your cylinders when you broke the head gasket seal. Some of them look like they have enough liquid in them to hydro-lock. I agree. That is a LOT of coolant in there. I would also agree with BBF. If the blower ain't broke, don't fix it, but that HVAC box is a must, and the rear coolant pipes if there is any sign of rust. When you get finished with it you may want to keep it. What year and model is it? Link to comment Share on other sites More sharing options...
MAC Posted January 28, 2007 Report Share Posted January 28, 2007 Background Bought the car real cheap with a known major coolant issue - assumed the worst (head gasket/bolts). Finished tearing down the motor today... and I was right! I am kind of surprised that only ONE of the bolts pulled out the block threads, and that just one bolt caused all this damage. A few others had little slivers of aluminum in their threads, so maybe they were starting to go as well. I had lots of coolant in 3 cylinders on the rear head. Time to timersert the block and start putting it back together. If you're thinking pulled head bolts caused the head gasket to fail I doubt your assumptions are correct. It's possible that "thermal fatigue" and/or neglected antifreeze caused the head gasket to fail. In fact, the older the Northstar the more likely head bolts will bond or lock with the aluminum block--The Guru (GM engineer) called this "galvanic activity." Poobah hit the nail on the head when he mentioned repeated heating and cooling of the engine (thermocycling) as a possible cause of a blown head gasket. I don't know about fire rings in particular but in general the head gasket would be the weak point not the head bolts. Thermal fatigue, however, is not an overarching concern. The Northstar cooling system is very efficient. One of the most important factors to a long lasting engine is maintaining antifreeze, i.e. change coolant at least as recommended and make sure thermostat is working properly. Link to comment Share on other sites More sharing options...
JohnnyG Posted January 28, 2007 Report Share Posted January 28, 2007 Also, the black plastic indicated by the red arrow was severely brittle from the heat of the exhaust manifold and cracked into a million pieces as I was dropping the motor. What are people doing to "fix" this? Leave it? Replace it with a new dealer piece? Other aftermarket/DIY solution That piece of black plastic looks fairly two dimensional, but the pictures may not be showing me everything. If that is really the case, I'd consider making one out of sheet aluminum before I reinstalled the engine. It certainly can't be any worse than a piece of plastic that is cracked. If it appears to protect something from the heat of the exhaust, maybe some thin ceramic insulation can be mechanically fastened to the back of the aluminum before installation. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
KHE Posted January 29, 2007 Report Share Posted January 29, 2007 The HVAC housig can be purchased from the online sources for $62.00. I replaced mine when I had the engine out as every time I bumped the old one, more of it broke apart. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
jcobz28 Posted January 29, 2007 Author Report Share Posted January 29, 2007 Sweet! Do you have a web link? -Jacob The HVAC housig can be purchased from the online sources for $62.00. I replaced mine when I had the engine out as every time I bumped the old one, more of it broke apart. Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 29, 2007 Report Share Posted January 29, 2007 Try www.gmotors.com and www.rockauto.com Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Kelly92eldo Posted January 30, 2007 Report Share Posted January 30, 2007 nice pics but from what I've been learning here, shouldnt that coolant be orange? Kelly Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 30, 2007 Report Share Posted January 30, 2007 nice pics but from what I've been learning here, shouldnt that coolant be orange? Kelly Good catch... Dexcool (orange) began in 96...that certainly does look green Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
chazglenn3 Posted January 30, 2007 Report Share Posted January 30, 2007 Larry; The profile reads "1996 Seville SLS". Hmmm...tried to quote your question above...oh well. Charles Charles Link to comment Share on other sites More sharing options...
Ranger Posted January 30, 2007 Report Share Posted January 30, 2007 Right you are. Link to comment Share on other sites More sharing options...
jhall Posted January 31, 2007 Report Share Posted January 31, 2007 Hi Guys, It's been a while. Glad to see some of my older post info is helping. An update on the '97 Deville in which I rebuilt the engine. I gave this car to my Brother-in -Law as a Christmas gift / repayment for his many favors. He's in the Reserves and has been logging lots of hours thanks to the Iraq effort. His car was flooded during a bad storm a few months ago and the insurance company totaled it. Naturally, the insurance payment didn't come close to a replacement vehicle - unless you count a used Yugo as transportation. I tossed the title to him and said to take it. The cruise was not working, but he took a chance on a used module via an internet parts site, we installed it and ta-da!, it's running 100% again. He just got a rear window leak fixed that was another little bug. He's getting right at 26MPG on I-95 with trips from Norfolk to North Carolina when he returns to see the family. Not bad for a N* with 150K+ on it! As for me, I bought a 2000 Deville. My wife already had a 2002 Deville, so we're pretty much committed to Caddy's. I've enjoyed the quality and ride. Link to comment Share on other sites More sharing options...
jcobz28 Posted February 2, 2007 Author Report Share Posted February 2, 2007 I think the green coolant is from an uncaring or uninformed previous owner. There is evidence of some weird things being done to try and get it to cool, before they obviously gave up and sold it. The thermostat was "there", but all internals were gutted. It was basically just the little metal ring housing, like they gutted the t-stat internals with a pair of pliers or something?!? (why not just remove the t-stat if you're going that route?!?)... although removing it is a bad idea anyways. I saw no orange coolant anywhere in the system when I drained it, so looks like it had been flushed thoroughly and filled with green. I drained the heads of coolant before I broke the head gasket seal. There was no coolant gushing out when I lifted the heads. The front head was totally dry in all cylinders. That's why I think the rear cylinders really did have that much coolant in them! I don't see any bent valves or things like that from a hydrolock condition. Just got $200 in gaskets from Murrays yesterday. Already got my used timesert kit from another forum member. Now just waiting for 20 threaded inserts from timesert to arrive in the mail. Then the drill/tap fun begins. Link to comment Share on other sites More sharing options...
chazglenn3 Posted February 3, 2007 Report Share Posted February 3, 2007 The coolant in the cylinders certainly explains the very clean piston tops. Good luck on your repair! Charles Charles Link to comment Share on other sites More sharing options...
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