HEAL-A-SEAL

[Cadillac Jim]

I wouldn't count the nitrous guy. Application of nitrous or supercharging to production engines without a teardown and careful purpose-driven build-up is a careless experient, IMHO.

Since it takes about seven years for a head gasket problem to become apparent in the older Northstars, then perhaps we shouldn't expect to have proof on anything newer than the 2002-2003 model year. We do know that at least 80% of 1993-1999 Northstars never have the problem, so I would concentrate on good maintenance, particuarly the coolant, cooling system, and avoiding low oil and low coolant.

Does anyone have any data or hard information on the Porsche 928, Infiniti, and others with an early production all-aluminum DOHC V8? My perception is that foreign manufacturers keep dealer parts and maintenance (what I call Integrated Logistics Support (ILS)) information to themselves and things like the sludge problems with Toyota four-cylinder engines and module problems with BMWs never come out, unless organizations of independent mechanics or aftermarket support people get wind of it. In fact, major end-of-life issues like the lack of a blowout plug in the DFI intake manifold of the Porsche 928 are often simply accepted quietly by owners of import cars; you just don't see many old ones on the road.

I think that the problem here is that nowadays we expect a car to last 20 years or more without a lot of teardown maintenance; I'm certainly looking at that with my Cadillac, although I've already replaced the engine and I'm willing to accept a transmission rebuild on that time frame. I think that the final solution to this problem is cathodic protection of the engine with replaceable zinc or other cathode rod in the head or block, to be replaced every few years with the coolant, like all hot water heaters that are guaranteed for more than two years. Perhaps it could be integrated with the coolant temperature sensor or the water pump, or the thermostat housing, or perhaps a separate device as part of the upper or lower radiator hose. Hey, I would consider something like that from an aftermarket source for my car. I would bet that cathodic protection of aluminum engines will eventually become as ubiquitous as surge tanks.

[MrEldo97]

“I think that the final solution to this problem is cathodic protection of the engine with replaceable zinc or other cathode rod in the head or block”

Strange that you mention that Jim; I ran a sacrificial anode in my Alfa spider (in the ‘80s) for years. This anode replaced one of the core plugs that were in the top of the head between the cams. I think it was called “Mag Plug” or something like that…? The purpose of the anode was to reduce the corrosion of Alfa head and block castings caused by a serious lack of cooling system maintenance (like no maintenance). In my experience I have seen Alfa Romeo block castings that were so badly corroded internally that they looked like they were full of sand and had been rendered unuseable. This anode would corrode in place of the aluminum. It worked; the anode would corrode over time (virtually no corrosion in a maintained system). I don’t think this “Mag Plug” has been available for years now because of the lack of a market. It should be searchable on Google if anyone is interested.

[Cadillac Jim]

I would be interested in one if it inlcludes my engine in its list of supported motors, it's reasonalbly accessible to the DIY person, and it's replacement period is at least a year. How about JC Whitney? They once were the absolute best for aftermarket support of older cars.

[MrEldo97]

I would be interested in one if it inlcludes my engine in its list of supported motors, it's reasonalbly accessible to the DIY person, and it's replacement period is at least a year. How about JC Whitney? They once were the absolute best for aftermarket support of older cars.

There are plenty of historical references to the “Mag Plug” on the web but no current suppliers. I really don’t think it’s been offered for sale for 15 years or more. I found that as long as you changed your coolant regularly (green every 12 – 18 months) the “Mag Plug” was minimally effective and really unnecessary.

In the top of the 4 cylinder Alfa cylinder head there are 3 or 4 core plugs. You removed one of them and installed the “Mag Plug” in its place. The “Mag Plug” was made in 2 parts; an aluminum hex of about 30mm across and a separate sacrificial anode (round, flat end, 3/8 dia x 1 inch long approx.) made from magnesium (?) – kinda looked like a sensor with a huge hex. I think they were also mounted in the V-6 blocks in a similar fashion. In any case their use proved to be unnecessary in maintained cars and they were eventually removed from the market.

[Cadillac Jim]

Hey, I found something from J.C. Whitney that fits my car, a zinc cathode device, that goes in the radiator cap hole and grounds to the radiator cap. If that is grounded, it will do the trick. Link:

J.C. Whitney Cathodic Proection for 1993-1999 Northstars

Price is advertised as $15. Thoughts, anyone?

NOTE: Caveat at the bottom says "not for radiators with plastic tanks" but the photo shows a brass radiator; I suspect that this is because those radiators don't necessarily ground the radiator cap. You might need to add a ground line to the Cadillac surge tank radiator cap flange, and I would run this ground directly to the engine head or block if I did it.

[MrEldo97]

Hey, I found something from J.C. Whitney that fits my car, a zinc cathode device, that goes in the radiator cap hole and grounds to the radiator cap. If that is grounded, it will do the trick. Link:

J.C. Whitney Cathodic Proection for 1993-1999 Northstars

Price is advertised as $15. Thoughts, anyone?

NOTE: Caveat at the bottom says "not for radiators with plastic tanks" but the photo shows a brass radiator; I suspect that this is because those radiators don't necessarily ground the radiator cap. You might need to add a ground line to the Cadillac surge tank radiator cap flange, and I would run this ground directly to the engine head or block if I did it.

For 15 bucks, sure...? You could try it for the s**ts and giggles factor. As I've "been there done that" I'll just continue to change my coolant regularly.

[Cadillac Jim]

One opinion, and not a surpising one for a J.C. Whitney gadget, and, yes, it seems that keeping OAT (red) coolant in the car and fresh is necessary in any case. I suspect that abusing the cooling system and allowing parts of the engine to run hot (running with low coolant, running with low oil) can eventually be damaging and that situation won't be helped by cathodic protection -- good maintenance is the best preventative. But, if you don't use distilled water, and the coolant does become conductive...

Anyone else?

[OynxSTS]

I wouldn't count the nitrous guy. Application of nitrous or supercharging to production engines without a teardown and careful purpose-driven build-up is a careless experient, IMHO.

Since it takes about seven years for a head gasket problem to become apparent in the older Northstars, then perhaps we shouldn't expect to have proof on anything newer than the 2002-2003 model year. We do know that at least 80% of 1993-1999 Northstars never have the problem, so I would concentrate on good maintenance, particuarly the coolant, cooling system, and avoiding low oil and low coolant.

Does anyone have any data or hard information on the Porsche 928, Infiniti, and others with an early production all-aluminum DOHC V8? My perception is that foreign manufacturers keep dealer parts and maintenance (what I call Integrated Logistics Support (ILS)) information to themselves and things like the sludge problems with Toyota four-cylinder engines and module problems with BMWs never come out, unless organizations of independent mechanics or aftermarket support people get wind of it. In fact, major end-of-life issues like the lack of a blowout plug in the DFI intake manifold of the Porsche 928 are often simply accepted quietly by owners of import cars; you just don't see many old ones on the road.

I agree that maintenance it critically important, My 2002 is now on its 4 batch of Dex...

But... and its a big but...

The numbers just don't support your hypothesis (that this is a coolant maintenance problem) How many times did BBF and other "in the know" board members "over maintain" their coolant only to have the head bolts fail? And why the HUGE drop in problems reported between 1999 and 2000... The Guru said they would start to fail at rates similar to the pre 99 models after they had been soaking in Dex long enough... But this just hasn't happened. The 2000's have been soaking for 9 years now and their failure rate is still a fraction of the 99 and earlier... Take a look at the "overheating" posts on this forum... the 99 and earlier out number the 2000 and newer something like 20 to one.

It also doesn't explain why the all aluminum LS1/2/3/4/etc engines are immune to this problem... They have been soaking in DEX for almost as long as NorthStars and the number of Head-gasket failures on stock engines is ZILCH. Oh and it gets worse... If you pull a head on a NorthStar for ANY reason you MUST timesert the block or you risk a future failure... How often do people timesert the LSx engines? Almost never... I know I guy down the street with an LS6 powered Vette and he has pulled the heads 3 times... ZERO time serts required.

This is not corrosion, this is not coolant related... this is either a bad casting or hardening process (i.e. bad blocks) or its the short fine pitched bolts that don't have enough meat to bite into.

[jock82]

I have a 1994 Concours that I have had for 15 years and it was maintained very well, the coolant changed on a regular basis by the Cadillac dealer, it has 102,000 miles on it and about 3 weeks ago I had a head gasket failure. I don't think it was the coolant that caused the failure.

[Texas Jim]

One opinion, and not a surpising one for a J.C. Whitney gadget, and, yes, it seems that keeping OAT (red) coolant in the car and fresh is necessary in any case. I suspect that abusing the cooling system and allowing parts of the engine to run hot (running with low coolant, running with low oil) can eventually be damaging and that situation won't be helped by cathodic protection -- good maintenance is the best preventative. But, if you don't use distilled water, and the coolant does become conductive...

Anyone else?

For 15 bucks...I vote to go ahead and use it.

It may not help anything...but just in case it DOES HELP...thats cheap.

I don't really see a down side...except spending the 15 bucks.

Make sure it is grounded good.

I have a cousin that works on barges on the Mississippi River.

They use big cathodes down in the bilge (bottom) of the barges where water collects and sits...sometimes for years.

Periodically they replace the cathodes.

Dirty, nasty job.

[BodybyFisher]

I have a 1994 Concours that I have had for 15 years and it was maintained very well, the coolant changed on a regular basis by the Cadillac dealer, it has 102,000 miles on it and about 3 weeks ago I had a head gasket failure. I don't think it was the coolant that caused the failure.

You would not know that until the engine was torn down, coolant leaking into the bolt threads would weaken them

[Cadillac Jim]

The reason that it's good practice to Timesert any Northstar that has been pulled down is that the factory uses thread lock and sealer that can't be replaced by a mechanic, and that often when this breaks loose it brings some aluminum with it. Early dealer instructions were not to Timesert head bolt holes where aluminum wasn't observed on the head bolt threads, but this doesn't account for the fact that the head bolt threads aren't sealed anymore on that bolt.

I've seen head gasket problems on these cars that I have owned that I remember casually: a Chevrolet 235 cid cold-water six, a Chevrolet 327, a 1986 Ford Escort, and a Northstar at 116,500 miles. I've seen aluminum corrosion problems on other people's cars including a Chrysler 440 (thermostat housing), a GM 3.4 liter V6 (intake manifold), and any number of aluminum radiator cores in the earlier days. I have not seen any such problems on big-block bowitie engines. All of these problems are seen after over ten years of daily driving and the vast majority can be traced to roots in poor maintenance, and an overheating event is nearly always in the recent history when a problem occurs. I have yet to see one in which a design defect is clearly an issue, other than very early AMC aluminum block inline six-cylinders (1961-1964 195.6 cid), which used conventional head bolts (not torque-and-twist) that would partially strip when the engine overheated badly.

Asserting that there is a dramatic difference in head gasket failures between the 1999 and 2000 models is premature in 2009 because we don't have enough time with the 2000-2003 models yet. One poster said there were big number differences; I would want to see those numbers, please, as they do exist as of now. A good comparison would be a plot of reported cases vs. numbers of posters who don't report cases, as a percentage. The percentage is important because the V8 has been losing popularity to the V6 since the late 1990s.

All BS and statistics notwithstanding, people who explode when any old car has a big bill are just not being realistic IMHO.

[KHE]

The reason that it's good practice to Timesert any Northstar that has been pulled down is that the factory uses thread lock and sealer that can't be replaced by a mechanic,

That is why NEW headbolts are required to be used when the gaskets are replaced.

All BS and statistics notwithstanding, people who explode when any old car has a big bill are just not being realistic IMHO.

I agree!

[OynxSTS]

Take a look:

Head gasket poll

1/3 of the reported problems between just 1999 and 2000... Hmmm me thinks me smells a rat.

And while we are busy reporting head gasket failures I had one go on a all cast 302 Ford Small block. That isn't the issue... The issue is NorthStars with short fine pitched bolts fail... NorthStars with long fine pitched bolts fail WAY less, and NorthStars with Course pitched long bolts DO NOT FAIL! You can't look at those facts and NOT point to the bolts as being the fundamental source of the problem.

I've been on this forum now for 5 years... If they are still around take a look at some of my historical posts... I noticed that everyone was complaining about problems with 97/98/99 engines about 4 years ago. The Guru said the problems will occur with the newer engines too... He is right, they do, but he is wrong, they occur at NO WHERE near the frequency of the 97-99 engines.

Look at that graph again... almost 75% of the failures occurred in the 97-99 engines. That isn't BS... that isn't statistical noise.

The reason that it's good practice to Timesert any Northstar that has been pulled down is that the factory uses thread lock and sealer that can't be replaced by a mechanic, and that often when this breaks loose it brings some aluminum with it. Early dealer instructions were not to Timesert head bolt holes where aluminum wasn't observed on the head bolt threads, but this doesn't account for the fact that the head bolt threads aren't sealed anymore on that bolt.

Interesting that this head bolt sealer issue, isn't an issue on the LS blocks... even though their bolts use sealer too... Half the time the LS guys reuse there head bolts with no issues...

[Ranger]

In the chicken or egg debate, I'm with Onyx 100%. You beat me to it posting that poll. Very unscientific, but speaks volumes none the less. There is also a "sticky" by a Cadillac mechanic in the Northstar section on the "Root Cause" of HG failures. He points to bad castings. Here it is.

http://www.cadillacforums.com/forums/north...ailure-fix.html

[MrEldo97]

IMO it's a number of problems - could be bad castings as well. I think that there is a tremendous build up of heat under the hood because of the front wheel drive and lack of space. This heat contributes to the breakdown of alternators and A/C compressors so why wouldn't it contribute to the head bolt problem? I suggest this underhood heat build-up greatly affects the rear head (my problem, the front was fine); that and headbolts that are too short with too fine a thread pitch and with miles and age we have failure.

Engineers screwed up on this one... Speculation to be sure, however...?

[Cadillac Jim]

deadlydeal -- if you are talking about Heal-a-Seal and other sodium silicate head leakage sealers, none of them are good for more than a patch. They work by drying sodium silicate into a leak in the head gasket when the engine shuts down, which then heats and forms a glass-like substance if it gets hot enough without being forced back out when the engine starts back up. If this can be managed, what you have is a weak or cracked head gasket shored up by what amounts to soft glass.

A few temperature cycles of gentle driving (one cycle?) and the seal is broken and the sealing process must be repeated. It may hold for some time in gentle driving around town if you stay at very light throttle and under about 35 mph. The first time you do a WOT exercise (i.e., pass a truck or deal with a difficult freeway on-ramp) you blow the whole thing back into the cooling system and start from scratch. The same will happen if you hold a steady highway speed for any length of time. This is true of any engine.

"This is no way to go through life, son." Or, to put it another way, I find this an unacceptable repair for my Cadillac.