: 4.6 Prevention and maintenance for longer life IE head gaskets.



Rodney_98
08-23-09, 11:05 AM
I've read the sticky on replacing the head gaskets and repairing the pulled threads on the N* engine blocks. I found this very interesting and at the same time was thinking... what have I gotten myself into! I didn't realize the potential and serious failure to these engines and cost beyond what my investment would be worth.
Unless I missed the information else where my questions are what is the best prevention a person can do to keep the head gaskets from failing.
The obvious is to not let the engine get hot.
What is too hot?
My 1998 d'ville temp runs just below199* and will climb to 204* in slow driving with the air on. I turn the air off and the engine cools down to the 190's.
The car runs strong with no leaking that I can detect. The radiator appears to have been replaced, I see two oil cooler ports on the passenger side on the tank that has nothing going to them so I would guess it was an after market part. The trans cooler lines are on the drivers side. I was concerned after seeing that no lines ran to the open ports but after looking at another 98 D'ville it had nothing running to the right tank either {no ports either}.
I have no history of the car so I don't know if the engine has been apart in the past.{I would have really like to known this now}

After talking with a mechanic who seems to be aware of the N* issues, he will be changing the coolant in my car this next week. He said all of the right things that gave me some confidence so I will have him do the job. I could do this but for 100$ he will drain and flush the system and install new Dex-cool to the system after he checks the hoses and as he said give it a good looking over. {sounds like a fair price to me}

Is there anything else I should ask him to take a look at while the car is in the shop?

With 127,000 miles on the car should I consider replacing the head gaskets now rather than later to prevent the potential issues.

Can a person use one of those little cameras that Snap on sells to look in the cylinders to see of a potential problem? I would guess the view a guy would need was from the cooling jacket area which may not be accessible.

Thanks for any input on my questions.

hendrob
08-23-09, 11:10 AM
Change the antifreeze every 2 years a least , best prevention you can do.

Rodney_98
08-23-09, 11:41 AM
Thanks
I pulled a spark plug out this am to see if they may have been replaced, what's installed are autolite double platinum
Is this an oem plug? I'd guess not, I discovered that no dielectric grease or never seize was used so I will be pulling the wires for now and grease the boot but so save ware on the threads I will not pull the other 7 plugs unless I need to. The gap on the plug I pulled was .045 which looked a little wide but I left it alone for now.

CadillacSTS42005
08-23-09, 11:56 AM
pull those POS Ford plugs and put in some delco plats
your car will run WORLDS better

N* gap is .06 or .05 (ones the gap for my LS1 the other is for the N* i always mix them up), the proper gap is on the id tag in the bay

Ranger
08-23-09, 01:16 PM
Normal operating temperature is 205-215. The fans don't even come on until 224 (except when the A/C is on).

Regular coolant changes is all you can do.

Why spend the money changing head gaskets that are not causing a problem? Why spend the money fixing a problem that may never happen? Cross that bridge when and IF you come to it.

Ditto on the Autolite plugs. Use A/C Delco 41-950's. (gap to .050)

Bore scoping the cylinders won't tell you much.

Necrosan
08-23-09, 02:05 PM
And you aren't supposed to use anti-seize on the threads of the plugs in Northstar engines.
Good way to send the plug back out the head.

Rodney_98
08-23-09, 04:47 PM
Sounds good to me I'll change the plugs for OEM and no anti seize tho I've used it for years on my Indy heads, Harley's ect.
My machinist will be interested to know it's not recommended..

I'll be interested to see how dirty the coolant is when it's changed.
thanks.

osu411yamaha
08-23-09, 08:28 PM
In my opinion its the acidity of the coolant that increases with time that is more detrimental to the coolant eating up the head gaskets than how dirty it is.

jcresciSTS
08-23-09, 08:32 PM
I just got my coolant flushed at the dealer at the beginning of August for $150 since I had no record of it being done. I also had an ATF Exchange done at the same time.

How's your Tranny fluid looking?

Ranger
08-23-09, 09:08 PM
Coolant doesn't get dirty. It will "look" just like new (unless it has sealant tabs in it. Then it will look a little muddy).

Rodney_98
08-23-09, 09:58 PM
Oh yes so true I'm thinking of an iron block {been working on old mopars for 30 years}
Owning an aluminum engine auto is new to this guy.
I'd guess the coolant in my car has been mixed with the green stuff, it looks like rusty brown
The trans fluid should be changed to since I don't know when it was last services.
thanks again.

Destroyer
08-23-09, 10:04 PM
With 127,000 miles on the car should I consider replacing the head gaskets now rather than later to prevent the potential issues.

For all you know the head gasket issue may have already been fixed on your car. :D

Ranger
08-23-09, 10:25 PM
I'd guess the coolant in my car has been mixed with the green stuff, it looks like rusty brown
That is most likely sealant tab residue causing that color. It's normal and nothing to be concerned over.

Rodney_98
08-24-09, 08:37 AM
That's good1 I'll still get the fluids changed and when its up on the lift see if I can take a look at the under side and see if I can find a rattle on the right front area, I also hear a click noise when turning at very slow speed from the same corner of the car.

blb
08-24-09, 09:44 AM
Since the failure mode is the headbolts pulling out of the block, there is really nothing you can do. Normal maintenance like changing the coolant is always a good idea, but it won't prevent the bolts from pulling out of the block if that's what's eventually going to happen with that particular engine. Not all Northstars fail in this manner, but many do. Not worth losing sleep over. If you are that worried about it, but really like the GM V8 FWD platform, unload it now and buy an '06 to '09 Impala SS with the LS4. It's much quicker, much more reliable, and gets better fuel economy.

Rodney_98
08-24-09, 10:02 AM
Since I got into the car for less than 3k I'll do some maintenance on her and enjoy what miles she has to offer.
I've seen re manufactured 4.6's offered for $3-4 k, if it dose come to fixing it that may be the way to go.
I'll cross that bridge if I come to it.
We do enjoy the car and worth some investment to keep it around.
thanks

ponyboyt
08-25-09, 10:05 AM
not sure im remembering right.... naw im pretty sure.. i was quoted a price a lot less than 4k (canadian) for a N* with studded heads.

anyhow, i'd like to know the proper way to check my head bolts. I assume i cant just unscrew one and screw it back in to specified torque. I want to see what size they are, as the engine was purchased in 2002. (for a 95)

Ranger
08-25-09, 10:46 AM
:tisk: If it ain't broke, don't fix it. Leave those head bolts alone and let sleeping dogs lie. They have a thread locker on them. Many times just removing them will take some threads with them. ONLY remove them if the heads are going to come off and the gaskets replaced. When doing that, a good thread will snap loose with a crack sound. If it doesn't, then the threads are bad for sure.

Rodney_98
08-25-09, 10:53 AM
I'm pretty sure that information is Here (http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/133429-root-cause-head-gasket-failure-fix.html).

Rodney_98
08-29-09, 11:39 AM
Update on my maintenance:
The mechanic drained the coolant, pulled hoses and thermostat flushed the system to remove all of the ugly old coolant replaced all of the hoses and reinstalled what he said was a new 195* thermostat replenished the Dexcool with new. I also has him service the transmission, all looked good but the fluid was defiantly ready to be changed and suggested it be changed every 24,000 from now on. I don't think $195 was a too much for what he did and it was good to have another set of eyes give the drive train a good look.
I have a clunk on the right front side which we discovered the sway bar bushings needing to be replaced, I'll do that once I get the parts.
The cooling temp now runs a solid 196* most all the time when 90* outside, I am pleased and will now enjoy our new Cadillac, they sure are nice riding cars.
Thanks for the advice all. :)

Submariner409
08-29-09, 01:55 PM
Right where the temp should run. The thermostat is set to begin at 188 and be fully open at 206, so most Northstars run (in all weather) with the thermostat about 75% open, especially when any A/C mode is set, as the fans then run in slow all the time. You will see the temp creep up to 224 in traffic with A/C off, then fans go to slow, cool down to about 210, then turn off until the next cycle.

Destroyer
08-30-09, 09:41 PM
There is a way to prevent the H/G issue on the N*. Surprised nobody has figured it out yet. :cool:

jcresciSTS
08-30-09, 09:46 PM
Let me guess...dont buy one?

osu411yamaha
08-31-09, 12:13 AM
Always interesting when Destroyer makes a post. I can relate to him as he isn't afraid to go against the grain and speak out on his opinions. There is a way to prevent it and it is not to buy an 04 or older northstar. I can promise you the head honchos at GM have had their materials engineers design something else major that will fail at 100k on the 05+. Mark my words....... We wont know until around 2012 and after until the warranties start expiring though. I dont care what anyone says. I studied engineering and I know if parts can be designed to NOT FAIL for certain time periods then they can JUST AS EASILY be designed TO fail after a certain time period. I have said it before and I will say it again. Why would GM want to build a car that will run forever. Its in their best interest for your car to fail right after the warranty expires so they have a better chance of you purchasing a new car.......

Rodney_98
09-02-09, 07:13 PM
Ok The engine is running nice and cool with the new coolant installed.
Now I have my GM service manuals for the car and have been reading on the cooling system flush procures. I read that they recommend P/N 36346321 cooling system pellets {3} to be added to the bottom radiator hose before filling the system with Dex-Cool.
My question is: should this be done every time the system is flushed or only on new engines?
If I should have had them put in with this flush is it that important to put them in the bottom hose? I really don't want to have the system drained again to do this.
Wish I had the service manuals before I had the system serviced :(
FYI I have a friend who has 170K on there 98 Deville had still running strong, with now major work done to the engine. I did suggest the cooling system be serviced soon!

Ranger
09-02-09, 07:58 PM
GM (and I) quit using them. Personally I would leave well enough alone. Read up on them in the sticky in the Northstar section.

Superjim
09-02-09, 10:07 PM
I dont care what anyone says.
I studied engineering and I know if parts can be designed to NOT FAIL for certain time periods then they can JUST AS EASILY be designed TO fail after a certain time period.

I have said it before and I will say it again.
Why would GM want to build a car that will run forever.

Its in their best interest for your car to fail right after the warranty expires so they have a better chance of you purchasing a new car.......


Well Mr. Engineer...
Your last statement...Thats the goofiest thing I have heard in a long time.

If all GM cars and trucks had a MAJOR COMPONENT FAILURE as soon as the warranty expired...NO ONE would EVER buy another one.
Including me.

I have been buying cars and trucks since 1960, and believe me, I have bought a bunch of them.
A very large percentage of them have been GM vehicles, for the simple reason that, at least for me, they give LESS trouble than other makes.

I currently own two vehicles and BOTH OF THEM are GM.
One 2006 Cadillac DTS and one 2006 Chevy Express van.

I had three 1999 Chevy vans before this one that I bought at the same time.

When I got rid of them..
One had almost 125,000 on it...never in the shop for ANY KIND of failure.

Another had almost 200,000 on it...never in the shop for ANY KIND of failure.

The third one burned in my garage fire in November of 2006, along with my 2006 DTS.

At that time it had almost 250,000 miles on it and had only been in the shop "ONE TIME"... and that was to replace a little vacuum line that makes the AC blow out of the dash vents.
I don't really consider the little vacuum line a "MAJOR COMPONENT FAILURE."

I replaced it with the 2006 Chevy van I am driving now.
It now has over 71,000 miles on it, and it has "NEVER" been in the shop for "ANYTHING."
It is "LONG" out from the factory warranty, which was 36,000 miles.
No MAJOR FAILURES...yet.

I replaced the 2006 DTS which burned and had 40,000 miles on it, with a new 2006 DTS that now has over 66,000 miles on it.

The DTS had a couple of minor electrical problems, when new, which were promptly repaired under warranty.
It has never had a "MAJOR COMPONENT FAILURE"... at least so far.
And yes...it is out from under the factory warranty, which was 50,000 miles.

In almost 50 years of buying GM vehicles, I can not remember EVER having a major failure as soon as the warranty runs out.

As long as I continue to get the great service from GM automobiles, like I have so far, "I" will continue to buy them.

"You" don't have to.

Texas Jim

ps:..maybe you can get one of math buddies to figure the statistical probability of me always getting a GOOD VEHICLE...that don't have major failures as soon as the warranty runs out.

osu411yamaha
09-03-09, 04:09 PM
Well Mr. Engineer...
Your last statement...Thats the goofiest thing I have heard in a long time.


"The exact contrary of what is generally believed
is often the truth."
-- Jean de la Bruyère

Superjim
09-03-09, 04:58 PM
"The exact contrary of what is generally believed
is often the truth."
-- Jean de la Bruyère


I don't understand what you mean.
I am not very educated.
I only finished the 8th grade.
Please explain the obtuse reference.

I was just saying that for me, and for a lot of people I know...we have had very little trouble from GM cars and trucks.

The DTS I have now is my 12th Cadillac.

My 1980 Sedan deVille, that I bought new and kept for over 20 years, had over 250,000 on it and was as trouble free of a car as anyone could ever wish for.
Same with the 1984 Fleetwood Brougham d'Elegance that I had for 17 years.

No one that "I" know, has ever had a major failure just as soon as the vehicle is no longer under warranty.

I interpreted your last statement in the previous post that I alluded to...to mean that major problems were very common, because GM actually engineered them to fail.

If I misconstrued your meaning...I didn't mean to...please enlighten me.

Texas Jim