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6K views 30 replies 15 participants last post by  chazglenn3 
#1 ·
I just found out from the Cadillac dealer that my 1996 Cadillac Deville (Northstar 4.6) head gasket needs to be replaced. The car drives beautifully and only has 72,000 miles. I was told that the repair is quite extensive and will cost $4500. I recently bought my car for $5000 when it had only 66,800 miles on it. I came across a product called THERMAGASKET and I wanted to know if anyone had a good or bad experience with it. I will either sell this car for $3000 or I will attempt to use THERMAGASKET to see if this can repair a bad head gasket. DOES ANYONE KNOW OF A BETTER PRODUCT ON THE MARKET THAN THERMAGASKET? PLEASE HELP
 
#4 ·
Doesn't 4500 sound a little high to you guys. Aren't they usually 2800 - 3000 or so?
 
#7 ·
I second the remanufactured engine. I highly recommend Custom Innovations. They sell their engines through eBay. I bought mine for $2899 and shipping was $99. Now labor was a whole different story...but you may be able to get the motor bought and installed for around the price the dealer is quoting you for a head gasket repair. Check around. Here is a link to their last auction...call Dave and tell him "Charles from Seattle sent ya!"

http://cgi.ebay.com/ebaymotors/93-9...8QQihZ003QQcategoryZ33615QQrdZ1QQcmdZViewItem
 
#9 ·
I think it's been stated that the mileage, per se, has nothing to do with a HG failure that is caused by coolant loosing its protection ability. The question to ask is, "has the coolant ever been changed?" and if so, WHEN? It's very possible, with such low milage, that he's still got the factory Dex in there, and I don't care what the mileage is, after 11 years, it's probably due for a drain, don'tcha think?
 
#11 ·
That was a little sarcasm Jim. The dexcool and the milage. If you havn't noticed, in the past, I've always said I can't understand why anyone would run the coolant more then 2 years, dexcool or green to save $20. And also that lately, it always seems to be a 96 & up N* with headgaket issues. Dexcool??
 
#12 ·
That was a little sarcasm Jim.
Ahh...sorry - I guess I didn't get the the nuance of your inflection.. :) :bouncy: :rolleyes:


You're right, though - 20 bucks every two or three years, it boggles the mind how some people just don't even consider it. Coolant and oil are the lifeblood of these cars, and yet....
 
#13 ·
I just wanted to share my experience with thermagasket with the group. First of all I really appreciate the information found in this forum and have spend many hours reading the information that is presented here.
I don't believe in miracle in a can as a long term solution but I was given a 2001 Deville with about the worst case scenario. Coolant in the oil, clouds of white smoke headed out the tailpipe but yet the car ran decent still. In my experience if you have coolant in the oil you might as well call the engine done and put in another. Every engine that I have had this condition and tried to replace the head gaskets after the fact came apart internally especially on the crank mains and rod bearings. The car was driven by the last owner in limp home mode for a good distance.
I drilled two holes in the thermostat at the suggestion of the guy at RxAuto and flushed the system with the heater on full blast at least five times. Each time I got the air out of the system by removing the hose leading to the overflow. I ran the engine with that hose loosely connected until there was a steady flow from it. After I was 100% sure that the coolant was all out I turned my attention to the oil. Since I was running the engine with the fouled oil in it to flush the system I had added Marvel Mystery Oil to the mix to try to keep the top end lubricated. The last time I got the engine hot I put a large pan underneath and let it drain for three days. I also poured clean oil into the engine during that period until only clean oil was dripping. I also removed the filter and let it drip from there as well. Next it was time to add oil and a fresh filter to the engine. I left the oil a bit low just in case water started back into the crankcase. I added some CD2 and Marvel Mystery Oil back in and fired it up only getting it slightly warm. I poured in the Thermagasket into the top hose as water emptied out of the block. I admit I was skeptical. I again filled up with water and took the air out of the system. I turned the heater off before starting the car and started heating it up. Still saw clouds of smoke pouring out the pipes. I held the RPM's to about 3-4k for about 15 minutes and then turned the car off and let it cool completely. I do mean completely cold. I am surprised at how long it takes for these engines to cool completely. Took about three hours. I then got my cell phone and climbed in again this time to take it for a ride. Smoke continued to pour out of the car for the first few miles and then the average mileage started to climb. The range numbers did as well. After about 15 miles I pulled back into my driveway and almost all the smoke was gone. Now it was time to cool it down again. Had to wait another three hours. I was a bit concerned since I was hearing a slight noise out of the engine but by the third time driving it was running so good that I could not believe it. Each time the temp was steady at the middle mark. It should also be noted that the directions stated to run the car in third gear instead of drive. The only reason that I went through all of this was so that I could see if this engine was worth pulling apart and fixing or if I should just be saving up for a new engine. So far I have taken it just over 100 miles and plan to run it at least to 1000 before I am going to be willing to tear this thing down and put in timserts. The company says that this is a permanent fix however I have no way to tell for any certainty yet but will post up a result after I run this thing for awhile.
 
#15 ·
I recently had success fixing a head gasket problem (huge white smoke screen) on my 1999 Seville STS w/101K miles using Bar's Leaks Head Gasket Repair about $9 a bottle. Just like Thermagasket you need to flush all coolant first. Used 1 bottle and followed the directions. There was some improvement, but still smoking. After doing some web research, I found folks recommending leaving the product in and driving for up to 500 miles before flushing and replacing with the proper coolant mix. So I added a second bottle and drove it for about 2 hours. All visible smoke was gone. Bar's Leaks claims this is a permanent repair. I can't attest to that since I decided to trade it in. Just thought I would share another much cheaper option. Also heard good things about KW block seal ($7) used in the same manner.
 
#16 ·
Interesting reading. The concensus is that the stuff in a can seals it up for a little while. It's not good enough to put your wife and kids in the car and send them on a trip across the Mojave desert but good enough to sell it to a sap you don't know. Situational ethics at its best.
 
#17 ·
Here are some thoughts on your "Situational ethics" comment. In my experience no dealer has ever been honest with me. When I bought this vehicle, it had latent electrical problems that only I was able to fix after much research and troubleshooting. To the best of my knowledge the head gasket repair is permanent. I chose to purchase a new vehicle and accepted a trade in value that was far less (~ $3500 less) than the value indicated by various online sources (Kelly Blue Book, Edmunds, etc). I could have sold on ebay to an individual for much more, but I have empathy for the buyers. Judge not lest ye be judged
 
#18 ·
Here are some thoughts on your "Situational ethics" comment. In my experience no dealer has ever been honest with me. When I bought this vehicle, it had latent electrical problems that only I was able to fix after much research and troubleshooting. To the best of my knowledge the head gasket repair is permanent. I chose to purchase a new vehicle and accepted a trade in value that was far less (~ $3500 less) than the value indicated by various online sources (Kelly Blue Book, Edmunds, etc). I could have sold on ebay to an individual for much more, but I have empathy for the buyers. Judge not lest ye be judged
Not a bad idea. A dealer has a higher responsibilty to a buyer than a private seller. At least the next owner will have limited recourse to the dealer unless the dealer dumps it at an auction.
 
#19 ·
I have used block seal and other products with great sucess especially when an engine has sat many years before running it in the transplant car. I put a 1969 400 Pontiac Engine into my 74 Lemans using that product and the engine still runs to this day. I was planning to use a low cost product first and then try a more expensive one if that didn't work. The down side of Block Seal is that it does require several days to dry when in a humid climate and here it is always just that. On another note the same company makes this product which you can get from a local NAPA store. http://www.crcindustries.com/auto/content/prod_detail.aspx?PN=401232&S=Y
I was going to try this Nanotechnology product first but my wife suggested that I go with the more expensive product. Once I got it though I saw exactly what others had seen. The warranty states that you have to fix the car to get your 100 dollars back. As such I was going to make sure that it worked. True there are several reasons it won't work especially if you don't get all of the coolant out. The directions also state not to run your heater with the product in the car. I had a far worse problem with the coolant in the oil however. I have worked on many cars and never was able to save an engine in this condition. Initially I was planning to tear down the engine once I got some miles on it but now since it is running so good I have decided to just run it till it dies and start looking for another engine to put it. I have used this company many times in the past and have found their engines to be excellent every time. http://www.asapmotors.com/
I have one of their import engines in my Honda and it is now approaching 300k on the car 150k on the engine that I have put on plus whatever mileage it had when I got it.
You can buy a Northstar from them for $1895.00 plus shipping unless you live in Texas or are willing to drive to Houston.
 
#20 ·
Here is the problem with the Northstar engines, especially those made prior to about 2003 or so.

When the head gasket goes, the head bolts pull up through the block, stripping the threads. Dealer has a $1500 digital tool that most garages do not have. Your engine is essentially done. Cheaper to buy another CAR.

You would be hard pressed to find another 96 Northstar with 50 or 60 k miles on it. Plus labor to install engine. Buy a LeSabre. Almost as comfortable, and much less potential for significant repairs.

Some of the problems come from the second small fan belt that many garages and customers do not know about. When that breaks, water pump quits working. 250 degree temp.

Northstar engine was designed to limp home when it overheated. Cadillac originally advertised it that way. When was the last time you saw that ad????

Caddies are pretty and comfortable. In my opinion, if you want a good Caddy, go with a 93 with 4.9 engine. No such problems with that engine.

Ed
 
#21 ·
Where are you getting your information from?
Here is the problem with the Northstar engines, especially those made prior to about 2003 or so.

When the head gasket goes, the head bolts pull up through the block, stripping the threads. Dealer has a $1500 digital tool that most garages do not have. Your engine is essentially done. Cheaper to buy another CAR.
Head gaskets usually fail from poor cooling system maintenance.
Head bolt length & thread pitch was changed in 2000 to make them more reliable.
Pulled threads can easily be repaired with a Timesert kit.

What $1500 tool are you talking about?
 
#22 ·
Well I figured I might as well see how long this stuff really lasts. So far I have along with my wife put on just over 4500 miles on the engine and it runs great still. The only residual effect I have seen so far is that the check coolant message never went away. In working on other cars I suspect that the sensor in the overflow tank is bad and likely as with other cars the entire tank must be replaced. No overheating at all. I will get a good idea of how good this stuff is when temps here in TX reach over 100 for extended periods.
 
#23 ·
Theres been about 757,848,465,849 posts about head gaskets, but here we go again. Make sure its the headgasket, dealers are alot of bullshit, take it to a well known shop and ask for a cylinder leak test. Or check for coolant in the tailpipes and milky oil. You are playing with fire putting that crap into your engine. Its kind of like putting a single band aid on a 6 inch cut. There's a couple ways to go here. First you need to decide if you want to keep the car, chances are this is only the begining of repairs, at least it was in my deville. If you do want to keep the car either stop driving it, or order a new or remanufactured engine. My experience with pour in fixes is that they usually do more harm then good. Besides the fact that they pretty much clog anything in your cooling system, the stop leak is only a temporary fix, if that. When your head gasket does blow, and your engine gets up to about 250 or 260, you really run the risk of damaging alot of crucial engine parts. Has your engine gotten this hot? If it has you really need to change the oil, because it got baked by the heat. If you decide to repair your current engine, 4500 dollars is rediculous. I paid 3500 and that was with timeserts, and my mechanic usually is working on vipers and other exotics. Personally i think you are better of replacing the engine or do what i did, get rid of it.
 
#24 ·
I am not a shop and I have built almost every car I have ever driven. This car was given to me because of my skills. If you looked at my past post I gave a link to a company that sells engines at a reasonable rate which I am planning to use to replace this engine in my car eventually. I have installed and drive a car with one of their engines and have had excellent results. I have all the tools and skills to do this work, and I realize that most who drive newer Caddies do not. I have no intention of getting rid of the car no matter what happens even if I end up towing it home as an end result. I am running this experiment to see how well this stuff holds up. I am giving the engine hard and taking it up to decent RPM's to see what will happen. Since the car is already going 80 MPH at just over 2250 RPM's I can't really take it much higher than that on the highway but I enjoy the sound of this V8 as I get it over 3k from a standstill. If you run the heater with any kind of additive in the system then you are just asking for trouble. The directions with Thermagasket makes this clear as well. They claim it is permanent and I want to see just how well it holds up. I was very meticulous in the way that I applied this product because to get your money back you have to get the car fixed by a shop or have the bill to present to them. I didn't want to tear it apart yet since I have several other cars I am building and wanted to drive the car. As to any doubt on the head gaskets there was none. I did however neutralize the acid that forms when the coolant and oil mixed and was sceptical myself on whether this would work or not. Now since it did work I am trying to see how long it will last. I have gotten lots of technical information from this forum and appreciate the insight that others have given me.
 
#26 ·
Here are the results of driving the car hard after using Thermagasket. I got just over 5k miles without any overheating. Just over this the car again overheated but this time without the oil and coolant mixing. I drove it hard as if thought nothing was wrong with it to really put this stuff to the test. Now it's time to fix it right. I got just enough time to really like the car and now to want to fix it right. The result again affirms what I knew and others here attest to. No product in a can will fix a nothstar for good.
 
#27 ·
I have a 94 with N*, it wasn't the gasket that went but the head bolt threads. I put in new timecerts, new gaskets for abt $400.00. It's not a job for the timid, pulling the heads and drilling the block with the engine in is difficult but not impossible. Car ran great until my wife accidentally put the car in netrual at around 80MPH and spun a bearing!!
 
#28 ·
5k for a pour in product is better that I ever expected, im impressed. Never thought it would go tha long. You are replacing the engine it that right? Yea I am not sure why women have the uncanny ability to destroy a perfectly good car cosmetically and mechanically, almost like a superpower id say. Good luck
 
#29 ·
Strange, the flat rate on cylinder heads or the engine is 17.5 or 17.2 hours, even if you add another 8 hrs for "extras" you will never come up to $4500 even at $100 per hour cause I sure dont believe the parts cost no $1000 bucks (but I may be wrong)plus.
sounds fishy.
From what I heard/read/saw you simply unhook all relavant connections to body and drop the front sub out of car and make repairs as needed.
From what the aftermarket horrodders tell me that out of the car the heads come off in couple hours or less and according to what I was told by 3 Caddy techs the cars sit for a day so as to make the job look longer as most have them completed for the most part in one day. This being the fact that if they do drop the sub they would have to realign the car(max 1hr).
and mopst i would say would have car in afternoon before removal to drain fluids and start disconnection process.
As a flat rate tech I understand the price but $4500 seems way high.
I would have figured abot half that and for such a low miles car it would be a fine investment as after doing headgaskets and timeserts would pretty much have it ready for the rest of the life of car. You can also address any oil leakes if it had any in lower crankcase.
As for swapping the engine hech its barely broke in but it would be a good thing to sell to a hot rodder (depending on core charges).
 
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