: 98 northstar cooling system



JonnyO
06-07-05, 02:10 PM
my 98 SLS northstar is running hotter than in the past. Normal operation was always mid point on the temp gauge, now it runs to the right of the middle hash mark...sometimes all the way to the next mark.
The cooling level is normal, no signs of over heating or coolant loss.

114,000k on the car. Will a sytem flush help?

Also, I have noticed that the needle on the gauge will move quickly at times...when it is in between the middle and right hashmarks on the gauge.

EcSTSatic
06-07-05, 02:16 PM
Well it is getting warmer out.:D

A flush might help. When was the last time the coolant was changed? There are some instructions somewhere on the board to change/flush properly. Are your fans coming on like they're supposed to?

The jerky needle could be your gauge sticking. Not a serious problem yet.

JonnyO
06-07-05, 02:21 PM
10-4 on the warmer:rolleyes:

The fans do work properly. I am having the system flushed tomorrow...did look at the info on the site. Looks like adding the lubricant is important.

mtflight
06-07-05, 03:19 PM
The supplement is actually preventive for leaks (CANNOT be added to reservoir--must be to rad hose).

What's really important is that the coolant is replaced because of its anti-corrosion additives--they wear out over time (max 2 yrs with green, max 5 with orange Dex-Cool). Check the water pump tensioner and drive belt.

oldgamer
06-07-05, 04:12 PM
I don't think flush will help until you have wrong mix (it should be 50/50). Check the belt tensioner.

jupiter57
06-07-05, 04:24 PM
My, My, My! This thread is nearly 2 hours old and not even a single "You Need New Head Gaskets" Post! LOL

Seriously, I would explore and correct anything and everything that is not functionally perfect. It seems that these Northstars with higher mileage are prone to run a little hotter than normal due to some small deficiencies in the entire cooling system.
A few things to check: (Search through the "Overheating" threads to learn more)

1. Check your coolant purge lines for flow.
2. Check water pump tensioner and drive belt, as mtflight said above,they tend to stretch with age.
3. Check your radiator/Condensor fins for obstructions.
4. Check your pressure cap, a new one is cheap.
5. Carefully check ALL hoses and clamps. Replace any Factory "squeeze"type clamps. (Even a tiny pinhole can give you major headaches, any leak on a Northstar is a big issue.)
6. Replace your thermostat, they do get old and sticky.
7. Check your radiator for proper flow, mine was almost totally clogged.

Be very careful with your cooling system, one major overheat could kill your head gaskets, and I wouldn't think that would be good.

JimD
06-07-05, 04:32 PM
10-4 on the warmer:rolleyes:

The fans do work properly. I am having the system flushed tomorrow...did look at the info on the site. Looks like adding the lubricant is important.


Take the time to re-think the "flush" unless you really mean drain as much as possible and refill with the proper coolant mixture.

A flush implies running lots of water through the system which just about guarantees you will lose control of the desired antifreeze to water ratio.

Lubricant?

Ranger
06-07-05, 07:48 PM
Well it is getting warmer out.:D

FWIW, mine actually runs warmer (213) in the winter than in the summer (206). I think Bbob actually said that this is normal when I questioned it. Had to do with A/C fans running and thermostat opening more I think.

mtflight
06-08-05, 01:02 AM
Well mine can get hot in idle rush hour traffic here in Texas... I've seen the digital readout go up to 224... it cools back down when I begin to move... it's just not fun seeing it in the 210s and up. I wonder if I should try that "water wetter" or whatever it's called?

when cruising at a steady speed on the hwy (70-75 mph) I am around 196 - 201.

Concourson20s
06-08-05, 11:36 AM
You need new head gaskets. :D There it has been said.

powerglide
06-08-05, 03:47 PM
The supplement is actually preventive for leaks (CANNOT be added to reservoir--must be to rad hose).


I've been thinking....if you buy the powdered type, add it directly to the fresh coolant container, shake it up and mix it well, then add the mixed coolant to your reservoir during a coolant change, wouldn't that do it too?

BeelzeBob
06-10-05, 02:07 AM
I've been thinking....if you buy the powdered type, add it directly to the fresh coolant container, shake it up and mix it well, then add the mixed coolant to your reservoir during a coolant change, wouldn't that do it too?


Yes, that will work pretty well, also. It would certainly be better than just dumping the coolant supplement into the surge tank. I would still put it into the radiator hose, though, given the choice.

mtflight
06-10-05, 02:13 AM
Yes, that will work pretty well, also. It would certainly be better than just dumping the coolant supplement into the surge tank. I would still put it into the radiator hose, though, given the choice.

I just added "Water Wetter" to my pristine 50/50 distilled/DexCool mix.

I did so by removing an ~equal amount of mix with a turkey baster, and then pouring in the "Water Wetter" which is a clear orange/pink liquid (almost fluorescent). Normally I would not invest in such, but read many good things about it from forum members (hope it's not the placebo/Amsoil/Turbonateor effect).

IS there enough flow in there, to eventually fully mix-in the system?, or will the bulk of it remain in the reservoir forever?

Thanks.

Ranger
06-10-05, 11:43 AM
Alex,
Is this stuff liquid? If so there is a contant flow from the purge line so I would suspect it will easily get flushed through the system. The problem with putting the sealnt tabs in the tank is that they are not liquid and settle to the bottom. The flow is not strong enough to carry them out.

BTW, what is this "Water Wetter" stuff? What is it supposed to do? Sounds like a water softening agent.

mtflight
06-10-05, 12:22 PM
Hey Ranger,

Thanks for the reassurance. This "Water Wetter" is a clear orange/pink liquid that alleges to decrease the surface tension of water "by a factor of two", thus minimizing bubble size and increasing the surface contact of the coolant within the cooling system--and therefore heat transfer. It also alleges to have corrosion inhibitors beneficial particularly to aluminum engines.




This info is paraphrased from their "white sheet":
Dyno tests run by "Malcolm Garrett Racing Engines" showed a temperature 8 degrees lower than 50/50 mix on a 350 V8, over 3 hrs @7200RPM.


50/50 temp = 228F
50/50 with Water Wetter = 220F

The most significant improvement is when one runs just water (I'm not going there) vs water with water wetter... in which case it is:

plain water 220F
water with water wetter 202F

I have noticed "slightly" lower temperatures, but I can't say if it's due to the weather/humidity/temperature or driving habits.


I have not seen 224F again since I poured it in... but have gone as high as 219F... which is allegedly within the improvement expected...yet too early to tell.. and I dunno how fast it will blend into the system--or if it's still sitting in the reservoir and here I am experiencing some kind of placebo effect.

$8 at Autozone.:rolleyes2 (hope it ain't snake oil).

http://www.cadillacforums.com/forums/search.php?searchid=247032

davesdeville
06-10-05, 12:51 PM
I don't see why you'd bother adding this stuff. The northstars cooling system works fine, the fans don't even really come on until 225*F anyway I believe. I don't understand how this water wetter stuff is supposed to work anyway.

EcSTSatic
06-10-05, 01:21 PM
Well mine can get hot in idle rush hour traffic here in Texas... I've seen the digital readout go up to 224... it cools back down when I begin to move... it's just not fun seeing it in the 210s and up. I wonder if I should try that "water wetter" or whatever it's called?

when cruising at a steady speed on the hwy (70-75 mph) I am around 196 - 201.

This was a common problem on TurboCoupes. The guys in that forum put fan override switches under the dash to turn them on and prevent damage in situations like this.

Firewireman
07-12-05, 12:24 AM
I hear everyone talking about this "Dex-Cool" coolant. I did a google search and found Shell makes it as well as Pennzoil, is there a difference? Also, I see page after page of lawsuits being filed again this Dex-Cool stuff. If everyone in the forums thinks it's great, why are there so many lawsuits? :confused:

Ranger
07-12-05, 01:35 PM
http://www.cadillacforums.com/forums/showthread.php?t=35605&highlight=Dex-cool

Firewireman
07-12-05, 10:39 PM
Thanks, this helps.

phxmark123
07-14-05, 04:17 AM
My 97SLS has 143,000 and the only time the gage has read anything other than right in the middle was when I had a heater core problem, and then it over heated and ran terrible. I only drove it for about one mile like this. I read in one of these forums that Northstars have a air injection system that protects from overheating situations. How do I know this system is working correctly because there is no way I would have run my car 500 miles overheating like that, as reported you can do. Heater core fixed and the temp gage reads right in the middle again.

mtflight
07-14-05, 11:21 AM
...I read in one of these forums that Northstars have a air injection system that protects from overheating situations. How do I know this system is working correctly because there is no way I would have run my car 500 miles overheating like that, as reported you can do.

50 miles, not 500. The system is called "Limp Home." The engine itself is protected from damage, by shutting off 4 injectors and pumping air (this is why it "runs terrible" since it has basically half or less power); however, this does not mean your headgasket won't be roasted and you will have that repair to look forward to. It mainly protects agains terminal damages such as warping, rods melting, etc.

You are right, I would not use that system either--if possible, and turn the car off until a tow truck arrives.

mcowden
07-14-05, 12:26 PM
My 97SLS has 143,000 and the only time the gage has read anything other than right in the middle was when I had a heater core problem, and then it over heated and ran terrible. I only drove it for about one mile like this. I read in one of these forums that Northstars have a air injection system that protects from overheating situations. How do I know this system is working correctly because there is no way I would have run my car 500 miles overheating like that, as reported you can do. Heater core fixed and the temp gage reads right in the middle again.

The overheat protection mode you're referring to is called Limp Home mode. If it goes into that mode, you will definitely know it because it will have a lot less power, probably sound like crap, and there will be a message on the dash. If your car ever goes into Limp Home mode, turn it off as soon as safely possible. That system is not intended to help you get wherever you're going, and it's still possible something could be damaged as a result of the overheat. Don't take the chance if you can possibly avoid it. Turn it off and call a tow truck (or roadside assistance or the motor club, etc.) Don't just drive it the rest of the way to Grandma's house thinking everything is fine. It's not fine or it wouldn't be in Limp Home mode. Something probably needs to be fixed, and driving it further is only going to make things worse. Limp Home is only intended to keep you out of harm's way on the Interstate or Death Valley or Compton or wherever you might be that could cause you injury if you had to stop immediately.

BeelzeBob
07-15-05, 02:22 AM
In addition to the above information....the Limp Home "loss of coolant" protection system operates using the input from the engines coolant temperature sensor. It is nothing but software in the engine controller so it is always ready and available and it will work if the engine overheats. It only comes into play if the engine is overheating severely. You would know it by then because at least two warning lights would be on, the AC would stop working and a chime would be sounding an alarm. It doesn't prevent an overheat of the engine it protects the engine long enough for you to get to a safe place if the engine does overheat.

Dooman
07-26-05, 09:03 AM
I got three messages alright, one was COOLANT LEVEL LOW, then IDLE ENGINE and lastly, STOP ENGINE. Learned my lesson that day, do not try to drive even a mile home in this mode..