Lots of people have tried stuff on them. There's lots of plugging products out there. Do they work on a Northstar ? Sometimes, kinda for a short while. But the real fix is to send the engine out to a real rebuilder who can fix the real issues. The head bolts and holes which stretch out and strip the threads. It's more complicated than just adding some "junk" into the cooling system. Lots of posts on it everywhere. Google is your friend.

Steve

 

I've read all that and I know the real fix is to just fix it lol Is it really worth it possibly having to pay upwards to 3000 just to get that covered. I payed 1400 for it and the body and interior are in very good condition and it seems it's been well maintained? I guess is more question.

 

Is it really worth it possibly having to pay upwards to 3000 just to get that covered.

That's a question only you can answer, but it is the only option IF you want it to last. Dumping any repair-in-a-bottle snake oil in it will be a temporary fix at best.

 

I see that you're in Michigan. Talk to Joe Blau at Midwest Cadillac Repair in Palatine, IL - just NW of Chicago. He is the resident expert on Northstar head bolt repair problems.

As posted, don't use temporary fixit magic goop. It just makes future engine repairs tough or impossible.

If the rest of the car is in good shape it's worth the engine repair cost.

I need to ask the operative question: Have you checked the coolant purge line for flow?

 

I suggest you read about the various products (miracles in a bottle) out there. Pick one, then follow instructions carefully. A miracle is worth trying for 1/100th the cost, $30 vs $3000. (Just going off the price listed on this thread no experience personally).

As a side note:. "I just got it a week ago" motivates my recommendation...

 

It's been parked since it Overheated and I haven't checked the lines yet was going to do so before I did any big money repairs and I also read about the coolant resavoir having to be replaced and the purge lines as well because of getting clogged was thinking on doing that as well first.

How do I know or find out if someone has used such goop before on this engine any tell tale signs? Before I go any further with anything I guess that is a good question as well.


And also motivates my questions lol it is what it is I got it cheap and don't have 3000 to drop on it right now

 

Sealant use - muddy coolant in the surge tank, slickery brown goop in the coolant hoses.

Check out the purge line and the water pump drive belt tensioner pulley.

Rent an exhaust gas block tester from a parts store, go for a drive, come home and do the block test. You're sampling the airspace over the coolant to detect exhaust gases. That's the yes/no head gasket bolt hole failure test.

Stupid question........ What was the indication of "overheat"? What happened and where was the temp gauge needle/bar?

 

Ok thank you I'm going to do so!

 

I edited my last post to insert a question ............

 

Well it came across my dash shut engine off high temperature and the low oil and low coolant lights came on At that point I pulled over checked the tempature it was reading only 220 so I popped the hood seen a little bit of steam coming from the resavoir so I shut it off. Let cool down for twenty minutes so I could check the resavoir. When I turned the car back on it was still reading low coolant and the oil turned to zero oil life. I have not tried to drive it or have I tried looking at the purge line yet since then because 1. I don't know squat about this car or motor and 2. I'm scared of what I might find

I did smell gas in my resavoir

 

"smell gas" ............ exhaust fumes or raw gasoline? Raw gasoline would be practically impossible in the coolant.

Correct coolant level is 1/2 full, cold.

An engine overheat sets oil life to 0 and a coolant loss sets the coolant low message.

Is the water pump turning?

 

I'd say exhaust fumes.I do have a hole in one of mufflers as well. Water pump is turning.

 

I'm having similar isuses on a 96 DeVille ... debating the same thing ... my repair quote was $3200 ... I had already changed the theromostat, oil, coolant ... purge line is flowing ... haven't done resevior yet ... I have my own thread gong on ...I've seen a guy use it on a Caddy on Youtube ... but it was a 2005 .... Bars .... my car will drive mostly fine for 25 minutes ... then start rising up in temp ... sometimes it "runs away" to 255 , other times it goes to 236 and drops right back down to 206 or so ... the most recent advice was to take out my thermostat (even though I changed it already) and run it without one for awhile .... I ordered my chemical test online so I am still waiting for it ... it sucks doesn't it ... I can drive locally for the most part ... but can't trust it ...

 

======================
the most recent advice was to take out my thermostat
removing the thermostat will GUARANTEE overheating in a Northstar motor -

I can drive locally for the most part ... but can't trust it ...
easy to explain -
the amount of stress on the engine at idle is near ZERO -
driving around town also creates VERY little stress on the engine -

hard acceleration creates a LOT of stress on the engine -
and cruising at highway speeds creates "medium" amount of stress -

the more stress - the more exhaust gasses are pumped into the cooling system -

under low-stress conditions -
the purge line is able to keep up with the production of air in the system -

under high stress -
the purge line is overwhelmed with exhaust gas and simply can't purge it all out quick enough -

finally - there is so much air in the system that the water pump just can't move the coolant -
the result is a spike in engine temp = overheated -

by idling the engine - or shutting it down for a few minutes -
the trapped air gets purged out -
coolant begins to flow again -
the engine cools down to normal operating temp -

 

Hell yes it does. Because I was really liking how it was driving and then bam

 

..Has anyone mentioned to check the coolant fans? smaller comes on at about 222-224 - l;arger 236-238? Both should run all the time with A/C on ....

 

Both fans run

 

... I recently have been asking what the possibilities of buying a new thermostat that was bad out of the box were, 1 person said "not likely" but two lifelong mechanics said absolutley ... they have seen it numerous times ... that's when the one told me to run it without one for awhile ... which I am going to try soon. I have zero signs other than the overheating ... no white smoke (although people here will say Caddy's won't have that sign) no milky oil ... no ticking ... no loss of power ... but one guy told me pretty adamantly DO THE BLOCK TEST ... like 1,000 times ... I think they got tired of my bitching

 

======================
I recently have been asking what the possibilities of buying a new thermostat that was bad out of the box were,
1 person said "not likely" but two lifelong mechanics said absolutley ... they have seen it numerous times ...
it DEPENDS on what BRAND you bought -
that's why I always recommend either ACDelco - Stant or Gates - and that's all!

that's when the one told me to run it without one for awhile ... which I am going to try soon.
DO NOT RUN A NORTHSTAR MOTOR WITHOUT A THERMOSTAT - EVER - FOR ANY REASON -
in the "old days" removing the T-stat was not an uncommon thing to do -
the Northstar cooling system works differently and REQUIRES a T-stat

but one guy told me pretty adamantly DO THE BLOCK TEST ... like 1,000 times ..
come on - don't exaggerate - it was only 100 times -
and the REASON is that the BLOCK TEST is the DEFINITIVE test for failed head gaskets in the Northstar motor -

the test is fast -
takes only a few minutes -

the test is cheap -
you can "rent" the test kit for free from most auto parts stores -
you just buy a bottle of the blue fluid - around $8 -

the test is 100% accurate -
the ONLY way exhaust gas gets into the cooling system is due to failed head gaskets -

if you do the test correctly -
and there is absolutely no color change at all -
you do NOT have a head gasket problem -
HOWEVER -
ANY change in color IS a POSITIVE result -
lighter blue - clear - green - yellow -
the stronger the color change - the more exhaust gas in the coolant -

 

I know you can test themostats by throwing them in boiling water and seeing if it opens it's good if not it's bad

 

I read if you do that test you can't let the thermostat touch the pan ... have to hold it with plyers ... I know it's a stretch but what if the stat only acted up every so often or stuck on occasion ... who knows ... I do electric work ... I've seen plenty of things happen you wouldn't expect and no expert would have thought of ... I kinda figured the guys here wouldn't like the idea of "snake oil" and they don't ... I paid $4800 for my DeVIlle over 10 years ago ... 165k miles now ... drove it to upstate NY from Cincy 5 years ago no issue at all ... one day the battery was dead so I left it idling to charge the battery and walked away and forgot it ... 45 min later came back to it overheating .... pinhole in upper hose ... big mistake ... changed hose but then it's been running hot after 25 moinutes of driving ... sometimes overheats ... sometimes comes back down ... maybe one of us can be the guinea pig for the other ... whoever tries BARS first?

 

Lmao I'm thinking I'm going to pull my coolant tank and purge line replace them. And replace my muffler. I don't have white smoke or burning oil smell,my oil cap doesn't have milky oil on it and only other indicator I have at this point is exhaust smell or fast smell in my resavoir. I'm wondering if the catalytic converter might be bad and caused it to overheat maybe?

And I have a hot radiator hose with pressure

 

Lmao I'm thinking I'm going to pull my coolant tank and purge line replace them. And replace my muffler. I don't have white smoke or burning oil smell,my oil cap doesn't have milky oil on it and only other indicator I have at this point is exhaust smell or fast smell in my reservoir. I'm wondering if the catalytic converter might be bad and caused it to overheat me with pressure

I used Bars Leak on my 1999 Deville about 6 or 7 years old. I would not do it again unless I planned on keeping the car. My Deville is an excellent condition mechanically. It is in good condition cosmetically. I have had this car since 2003. I have replaced a lot of parts through out the years. It still has a smooth ride. I had the heads redone by a gentleman near Warner Robbins, Ga I found on eBay and this site. I have had no overheating problems in at least five years after the head job. After he did the heads, I changed all the parts that involved the traveling of radiator fluid because of the Bars Leak. Once I changed those parts the temperature stays around 203 degrees regularly. It was always about 210 to 218 degrees after the head job. I figure the Bars leak had clogged up my radiator and heater coil. His information is on this site if you can find my old posts.

 

I read one post where dude said he was told both is catalytic converters were bad ... I wish I could remember the outcome of that one but I don't think he believed them. My thread is labeled 96 DeVille overheat , sometimes i can't even find my own thread , LOL ... I'm newer here ... sadly I think your car is in the dreaded 97-99 years ... mine is just outside it at 96 .... there is a chart somewhere that tells you the chances of the HEAD GASKET issue after you vote for yours ... sorry I am not much help as I am in your situation and I'm not sure I have it in me to rebuild a damn engine ... especially one this complicated ...

 

"no white smoke (although people here will say Caddy's won't have that sign"
When the head gasket in my 04 blew the car belched out whitish grey smoke/steam from the tail pipe that smelled like antifreeze.

 

Our 16 or 18 psi pressure caps result in a pretty hard hose as normal system pressure builds, and the upper hose gets HOT when that 188+ degree coolant starts flowing. The 'stat is in the lower hose so practically NO coolant flows through the radiator until the rest of the system is at design temp. Pressure is equal everywhere in the system - as it is in any hydraulic system.

Our cars have special channels and clips for the upper radiator hose to prevent chafing on the engine.

A Northstar with advanced coolant loss due to failed head bolt threads WILL put out some steam.

Use a candy thermometer and place the thermostat in the saucepan "face down" so the wax pellet brass chamber points upward.

The Northstar thermostat begins opening at 188 and is fully open at 206. Most Northstars run at 190 - 205 all day every day so the 'stat is never fully open.

The cooling system must have a 'stat installed to function correctly.

The temp gauge is highly damped from 188 - 215 because if the needle moves in response to normal engine operating conditions many owners go freako.

Northstars use the same temp sending unit so the large or small gauge ticks and digital bars correspond to this picture.

 

Considering 1997,1998 and 1999 were the worst years for head gasket problems why are you guys looking at every other thing but the head gaskets first. Do the damn block test first for $8 bucks and either confirm or eliminate the most obvious and important reason for overheating in these Northstars. Then you can play with the other 5-10 reasons for overheating if it is not the head gaskets.

 

This is the best product I have come across so far. I've known a few people that have used it with great luck so if you can't afford the engine rebuild I would give this a try:

Amazon.com: BlueDevil Head Gasket Sealer (38386): Automotive

Buy BlueDevil Head Gasket Sealer (38386): Gasket - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

You can also get it at a lot of automotive parts stores.

Roy

 

====================
NONE of that stuff works on a Northstar motor -
crack a raw egg into the radiator -
you'll get the same results -

just consider the nature of the problem -

it's NOT that the actual head gasket fails -

the head BOLTS get loose -
and the head lifts up off the block -

 

I'm making the car a project car now and will be getting it rebuilt and replacing bolts and getting the inserts it makes more sense to me if I actually want to enjoy the damn car lol thanks for all the input I am going to test the block to just for confirmation but I'm still doing the rebuild regardless if I put money into it it'll last me.

 

======================
I totally agree - if the rest of the car is in really nice condition -
it's well worth putting the money into a "permanent" repair -

what kind of a used car can you find for $3000?
a high mileage econo-junk -

 

If they make studs for the heads on those engines I would suggest that instead of using bolts. See if ARP makes any for it.

Roy

 

If they make studs for the heads on those engines I would suggest that instead of using bolts. See if ARP makes any for it. Roy

You haven't been into the Northstar engine discussions long enough to see this - long time member who makes studs - www.northstarperformance.com

ARP studs (Volkswagen section) are another option, screwed into BigSert or NS300L inserts.

.............why are you guys looking at every other thing but the head gaskets first. Do the damn block test first for $8 bucks and either confirm or eliminate the most obvious and important reason for overheating in these Northstars. Then you can play with the other 5-10 reasons for overheating if it is not the head gaskets.

Please see Post #8.

 

Had it a week, like the way it looks......some of these posts. Did you bother checking it over before you bought it? Buy it from a reputable source? I don't participate much here (mostly Benzes, including V12s) but on my 4.5 Allante and 4.9 Eldorado, both 20 and 40k cars, I've done plenty of work, but knew what I was getting into and inspected them and bought them right. I get a lot of "see the latest posts on the Cadillac forums" in my email, and subject lines like these just blow me away. A lot of kids playing Russian Roulette out there......

My answer would be flip a coin and try stop leak, then see if you can pawn it off on Carmax for a grand and be smarter next time.

 

I have used Bars Leak many times, and it works wonders. Don’t use the stuff that is in oil. Only buy the lozenges in a plastic case. There are 7 or 8 lozenges in the packet. A/C Delco sells them also. Use all the lozenges and get the engine up to temp, system under pressure before you shut it off. Leave it off for overnight for best results.

 

Sounds like what you are talking about is the Barsleaks sealant tabs. They are meant to seal small niusence coolant leaks. They will do nothing to seal or prevent a HG leak.

If you overheat the engine just once, it may warp the head and then you have a HG leak. Happened to me

More misinformation. The Northstar was designed and tested to run 50 miles without any coolant with no damage. They DO NOT warp heads when overheated.