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What is normal engine temp for the northstar?

39K views 19 replies 16 participants last post by  Submariner409 
#1 ·
My car is a 96 deville concours

Its been running around 212' - 227'
Is this normal? :hmm:
 
#3 ·
:confused: I have been struggling with similar questions .... in normal moving traffic I stay at 196F ... but in crawling traffic I watch the temp go up to 222F before the fans kick in full, and then temp drops to 197 and the cycle continues ... I really don't like this and would like to be able to activate the fans full when I am in traffic and I see the temp go thru 200F. I am positive that constant 25 to 30 degree cycles cannot be good for the car .. and I fear pulling studs out of the block??? Anyone have thoughts on bypassing the full speed fan switch manually??? Thanx Vytas524
 
#4 ·
vytas524 said:
:confused: I have been struggling with similar questions .... in normal moving traffic I stay at 196F ... but in crawling traffic I watch the temp go up to 222F before the fans kick in full, and then temp drops to 197 and the cycle continues ... I really don't like this and would like to be able to activate the fans full when I am in traffic and I see the temp go thru 200F. I am positive that constant 25 to 30 degree cycles cannot be good for the car .. and I fear pulling studs out of the block??? Anyone have thoughts on bypassing the full speed fan switch manually??? Thanx Vytas524

Perfectly normal. Quite worrying. Better yet, turn off the temp gauge so you don't want to watch it all the time.
 
#5 ·
I've noticed this too. It is easy sometimes to get a "piece" of data...like a slight (but perfectly normal) spike in engine temp in traffic, and make a mountain out of a molehill by fixating and worrying about it...the way I look at N* engine temperature is this: The engine is designed to run without coolant if need be in "camel" mode. Therefore, if it gets to 250 degrees in traffic once in a while, no engine damage will occur...I just have to be aware that it doesn't boil over. I don't know what the boiling point would be, but under pressure, it's a lot higher than 212. dave
 
#7 ·
This post was informative and I have been wondering the same thing. I have a 94 Eldo and it works fine but I live in Phoenix where the temp can reach 120 F. Even on cold days it seems to sit at 216 to as high as 223 when I stop at lights for a minute or so. I am new to the N* engine and would like to know what the normal operating Temp should be. Not what the aceptable operating range of the Vehicle is. It is great that it can work under such Temp range and in my experience in Phoenix is that a car that is running such high temps will be suseptable to overheating once the ambiant temp increases to + 110 f. and you are stuck in rush hour traffic.
 
#8 ·
Jaimarti : I also have a 94 Eldorado and my temps are usually around 208-214 if i'm doing a constant speed over 30mph and if im just sitting it usually is at 225-234.. 234 being the hottest its ever gotten. Your car is fine up to 250 even, if you have the proper 50/50 mixture of coolant in system, it is made to handle up to 265 which is the boiling point. Even in the hot summers you describe everything should be okay as long as everything is functioning as it should (water pump, radiator cap.. etc), oddly enough you might notice your car runs cooler in the summer than the winter since your cars fans are running more often, my car hit 234 recently while its been cold.. if you do a search, ********* covers this subject thoroughly. Enjoy the eldo!
 
#10 ·
jaimarti said:
This post was informative and I have been wondering the same thing. I have a 94 Eldo and it works fine but I live in Phoenix where the temp can reach 120 F. Even on cold days it seems to sit at 216 to as high as 223 when I stop at lights for a minute or so. I am new to the N* engine and would like to know what the normal operating Temp should be. Not what the aceptable operating range of the Vehicle is. It is great that it can work under such Temp range and in my experience in Phoenix is that a car that is running such high temps will be suseptable to overheating once the ambiant temp increases to + 110 f. and you are stuck in rush hour traffic.

Nothing to worry aobut. Believe it or not, GM tests cars all summer in Phoenix so your Northstar was seeing those summer temps years before it went on sale to the public. Drive out to Mesa one Sunday afternoon and go south on Ellsworth road and see the GM Desert Proving grounds which has beena fixture in the desert southwest for decades.


You have to realize that the coolant temp is dictated by the thermostat control point in the engine , the air flow thru the radiator and the ambient temp. Just because it gets to 223 sitting at idle on a cool day does not meant that it is goint to go up another 40 degrees when the ambient is 40 degrees hotter. What you are observing is the system sitting there with no air flow and no cooling fans. It creeps up to 225 and then the cooling fans turn on. The cooling fans are not even needed or turned on until the engine temp is at 225....225 is "cool" to an engine cooling engineer and the engine is perfectly fine at that temp. It is designed and clearanced to operate at that temp.

With a fresh charge of 50/50 coolant/distilled water and a 15 PSI pressure cap on the system the coolant will not boil until 265 degrees F and, even at that elevated temp with all the warnings and chimes going off, the engine will be fine, protected and undamaged.

Trust me, it was designed to operate in those ambient conditions and even in hotter ones. The best thing that you can do if you are concerned about cooling performance is to make sure the water pump drive belt and tensioner is in good shape, that the system is filled with FRESH 50/50 coolant/distilled water and that there are no leaks in the system and that the radiator and condensor fins are clean and unobstructed. If so, it will be fine.

I have been in those cars in Death Valley with trailers in 124 degree ambients and they were fine. The coolant temps in those conditions will run upwards of 250F...which is hot....but fine....and what do you expect for 124 degrees...???
 
#18 ·
Nothing to worry aobut. Believe it or not, GM tests cars all summer in Phoenix so your Northstar was seeing those summer temps years before it went on sale to the public. Drive out to Mesa one Sunday afternoon and go south on Ellsworth road and see the GM Desert Proving grounds which has beena fixture in the desert southwest for decades.


You have to realize that the coolant temp is dictated by the thermostat control point in the engine , the air flow thru the radiator and the ambient temp. Just because it gets to 223 sitting at idle on a cool day does not meant that it is goint to go up another 40 degrees when the ambient is 40 degrees hotter. What you are observing is the system sitting there with no air flow and no cooling fans. It creeps up to 225 and then the cooling fans turn on. The cooling fans are not even needed or turned on until the engine temp is at 225....225 is "cool" to an engine cooling engineer and the engine is perfectly fine at that temp. It is designed and clearanced to operate at that temp.

With a fresh charge of 50/50 coolant/distilled water and a 15 PSI pressure cap on the system the coolant will not boil until 265 degrees F and, even at that elevated temp with all the warnings and chimes going off, the engine will be fine, protected and undamaged.

Trust me, it was designed to operate in those ambient conditions and even in hotter ones. The best thing that you can do if you are concerned about cooling performance is to make sure the water pump drive belt and tensioner is in good shape, that the system is filled with FRESH 50/50 coolant/distilled water and that there are no leaks in the system and that the radiator and condensor fins are clean and unobstructed. If so, it will be fine.

I have been in those cars in Death Valley with trailers in 124 degree ambients and they were fine. The coolant temps in those conditions will run upwards of 250F...which is hot....but fine....and what do you expect for 124 degrees...???
Bob you're good...Purchased a 1999 El Dogg with 117,932 .I'd love to chat with you about my 99 Eldorado and the correct temp in which the fans should kick on. The gauge sits at 12:00 consistently as I live in the Bay Area. Just got a check gas cap with a service engine light today...now I'm worried. Any solutions?
 
#12 ·
Thank you for the info. It was even more informative than I had hoped for. I feel more confident now and will take a trip down to the proving grounds. Coming from the cast iron era it is hard to believe an engine can run at what I would consider such extreme heat conditions I have also read alot of info on this site and I believe this is a good forum for information exchange and the folks that pass on knowledge to us less knowledgable folks deserve :worship:
 
#17 ·
chadillac said:
One day I was checking the coolant level and didnt put the cap on tightly and most of the coolant ran out and the low coolant chime came on. I filled the res tank with hose water now its been running warmer then normal. 212 before/now at 214-222.
Regardless of operating temperature... if you still have hose water in it, I would recommend that you have it drained, and supervise that they put in dexcool and distilled water (50/50) as well as the GM tablets OR two Barsleak tubes.

You do not want hose water in your cooling system!

-Alex
 
#19 · (Edited)
650, Welcome to CF !!! The post you quoted is 15 years old and the OP has not logged in for over 10 months - and is essentially an inactive member.

Your 1999 Northstar uses a thermostat set to begin opening at 188 and fully open at 206. The engine, with the cooling system in good condition, will run at 190 - 210 all day 24/7/365. Change the coolant every 3- 4 years religiously. Fans operate two ways - with an A/C compressor function set thy run in SLOW all the time to insure airflow over the condenser in front of the radiator. With no /C compressor function set the fans go to SLOW at 224 degrees and FAST at 236 degrees. The engine cools to 213, fans turn off, the cycle repeats - and this is in really hot weather or heavy, slow traffic. Fans don't run at over 30 mph - not needed.

Your gauge corresponds to mine - same number of tick marks, same temp sender.

Auto part Speedometer Gauge Measuring instrument Tachometer


The SES light is in response to an emissions fault - the gas cap message. It's part of the EVAP system. Here's a line diagram of the parts. You're looking for a slight vacuum leak in the system. Check the test port green cap - near the brake booster. Then you're into the charcoal canister rubber lines.

Your car has its own built-in code scanner. You use the correct model/year group of instructions in the sticky thread "How to pull codes".

Text Diagram Parallel Line art


Did you ever go back to your first post on the "overheating" question ?

 
#20 ·
This resurrected thread has a lot of good Northstar info in it - it's worth a full read.

There is a ton of later info in the sticky threads (marked with a push pin) in the Engines; Northstar forum.

This article also has necessary info, primarily for the pre-2000 Northstar owner. It was written by a CF member who was a GM/Cadillac Northstar Systems powertrain engineer.

 
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