Coolant Temp

97d'elegance · #1 (**permalink**) 04-12-04, 09:48 PM

Okay .. I know I have posted before asking about safe temps for my 97 deville but I have to ask again. Yesterday I drove to my parents house for Easter .. left around 10am but it was already warm and humid and the A/C was on AUTO and 71 as usual. It was a little more than 80 degrees outside and very humid. I was moving along at around 75 or so and I decided to speed up ... I nailed it and was going about 97 when I noticed the coolant temp raise steadily from 206 up to 233 ... this happened in about 20 seconds time. I slowed down a lot and it went back down to around 217 and hung there most of the remaining trip. I drove about 60 miles one way to my parents. I didn't go over 75 or so after that happened and was scared it was developing a problem. There was quite a bit of stop and go traffic (which I drive in on a daily basis). I have driven 97 and much faster many times before and never saw the temp get close to that. Last evening when I left for the trip home it was about the same temperature outside and still humid. The temp ran around 217 again for a lot of the trip .. I was in stop and go again and it spiked up to 230 this time ... I was only going around 60mph this time. It then went back down to around 212 until I got home. Traffic wasn't as heavy this time and I was moving most of the time. The coolant level is normal and the oil is full. It was hot again this afternoon and I took my regular trip down I-4 in stop and go to and from work. It never went about 206 today. I do NOT understand this car. I know I seem to worry a lot about this but I am totally paranoid that it will run hot and I will blow a headgasket. Is this normal? What signs should I look for before stopping (other than the warning lights). I guess what I want to know is what is the highest temp I can drive at before I pull over and idle to cool down? Thanks again Everyone!!

Anthony Cipriano · #2 (**permalink**) 04-12-04, 10:24 PM

Quote:

Originally Posted by 97d'elegance

Okay .. I know I have posted before asking about safe temps for my 97 deville but I have to ask again. Yesterday I drove to my parents house for Easter .. left around 10am but it was already warm and humid and the A/C was on AUTO and 71 as usual. It was a little more than 80 degrees outside and very humid. I was moving along at around 75 or so and I decided to speed up ... I nailed it and was going about 97 when I noticed the coolant temp raise steadily from 206 up to 233 ... this happened in about 20 seconds time. I slowed down a lot and it went back down to around 217 and hung there most of the remaining trip. I drove about 60 miles one way to my parents. I didn't go over 75 or so after that happened and was scared it was developing a problem. There was quite a bit of stop and go traffic (which I drive in on a daily basis). I have driven 97 and much faster many times before and never saw the temp get close to that. Last evening when I left for the trip home it was about the same temperature outside and still humid. The temp ran around 217 again for a lot of the trip .. I was in stop and go again and it spiked up to 230 this time ... I was only going around 60mph this time. It then went back down to around 212 until I got home. Traffic wasn't as heavy this time and I was moving most of the time. The coolant level is normal and the oil is full. It was hot again this afternoon and I took my regular trip down I-4 in stop and go to and from work. It never went about 206 today. I do NOT understand this car. I know I seem to worry a lot about this but I am totally paranoid that it will run hot and I will blow a headgasket. Is this normal? What signs should I look for before stopping (other than the warning lights). I guess what I want to know is what is the highest temp I can drive at before I pull over and idle to cool down? Thanks again Everyone!!

Relax. Sounds perfectly normal. Spend more time watching the road instead of the coolant temperature. Better yet, turn off the DIC coolant temperature reading. There are plenty of automatic warnings if things should get too hot. Relax and let them work. The system can go to 245 or 250 degrees with no problems on a high demand, heavy load situation. It's designed to work that way. With a 15psi pressure cap and 50/50 coolant mixture in the system the system will not boil until 265 degrees. So you're a long ways from any sort of "over heat" situation. Besides, the Northstar engine has a "loss of coolant' limp home mode that will activate automatically long before you get any thing hot enough to damage a head gasket or anything. The loss of coolant limp home mode is so effective that it's been proven time and time again to run the engine for 50 miles at 50 MPH without any coolant in the system without any engine damage. So you (and your engine) are protected even in your worst nightmares of an overheat or something. It will allow you to drive to a safe place even with all the warnings and chimes going off without any risk of damage.

Really, forgot what used to be normal for coolant temps on older cars. The systems are more efficient at cooling running at the higher temps, the engines are happier and are cleaner (for emissions and internally), get better fuel economy and last longer running at the higher temperatures. The cooling fans are only activated at 225 degrees or above so anything below that is considered ice cold by the engineers that designed the system. There is no need to slow down, pull over and idle or do anything out of the ordinary regarding the cooling sytem. Drive it and quit worrying.

Just service the cooling system every 5 years or 100K by draining and refilling with fresh 50/50 DexCool/distilled water to keep the corrosion inhibitors in the coolant fresh to prevent any internal corrosion. That's what causes blown head gaskets. Lack of cooling system maintenance over the long haul.

If you search using "coolant temp" or "DexCool" or "coolant" or things like that there is a ton of info in the archives of this site that should set your mind at ease.

julio · #3 (**permalink**) 04-12-04, 10:34 PM

I have bad gaskets, the tell tell sign is in cold weather when you leave the white cloud, in warm weather all you can do is wait for the low collant level. The northstar is aluminum if you're not loosing water then no worry, Check the belt on the waterpump, not knowing you engine or the last time you've changed the belt might be time for a new one. The other thing to look at is having the termostat changed, I 4 is orlando or Tampa, I'm in Jax I notice ,y temp guage running slightly over 220 in 85 +weather. make sure your fans are running. The other things that screw you up is if the computer is getting a good reading but the presentation is screwed up(the guage is broke) it's not worth tearing the dash apart and ask your service rep if he can test for a bad gage without raping you in the process.

Julio

97d'elegance · #4 (**permalink**) 04-12-04, 10:46 PM

Thank you Anthony! You put my mind at ease. First thing in the morning my DIC is going OFF! Thanks again!

Anthony Cipriano · #5 (**permalink**) 04-12-04, 10:51 PM

You'll be fine. The same sensors that send the coolant info to the DIC control the limp home mode and other coolant temp functions and that sensor is backed up by the onboard diagnostics for checks and remedial action if a failure is detected so there is little or no worry about the automatic system warning you if there is a problem. Unless red lights start coming on the system is fine. Even then it will protect the engine.

RLLOVETT · #6 (**permalink**) 04-13-04, 12:53 AM

(Stop me if I'm repeating myself, but...) My 94 had a 'limp-home' episode a few weeks ago and is using coolant without leaking it. The distinctive odor of ethylene glycol seems a little more pronounced each day. The dealer won't touch it ("too many miles"/129k), no independent mechanics will touch it ("I theenk it's intake gasket")...but I'm just wondering if the more noticeable odor is something that would keep me from adding coolant and driving it till it quits? Also, for a while, the 'low coolant' message would appear but not anymore--blown sensor? tired of repeating the same old story?

Olds3.5 · #7 (**permalink**) 04-13-04, 10:26 AM

I think that you are observing the "heat soaking" effect of the cooling system. When you are running, say at 75 mph, the combustion heat is in equilibrium with the performance of the cooling system. If you suddenly get caught in traffic or something similiar that causes you to slow down, the heat in the engine suddenly has to be dissipated by a cooling system with less air flow and slower circulating coolant (lower rpm). The temp may rise sudddenly temporarily at that point and this effect is called heat soaking.

Anthony Cipriano · #8 (**permalink**) 04-13-04, 12:17 PM

Quote:

Originally Posted by RLLOVETT

(Stop me if I'm repeating myself, but...) My 94 had a 'limp-home' episode a few weeks ago and is using coolant without leaking it. The distinctive odor of ethylene glycol seems a little more pronounced each day. The dealer won't touch it ("too many miles"/129k), no independent mechanics will touch it ("I theenk it's intake gasket")...but I'm just wondering if the more noticeable odor is something that would keep me from adding coolant and driving it till it quits? Also, for a while, the 'low coolant' message would appear but not anymore--blown sensor? tired of repeating the same old story?

Dose it heavily with the GM coolant supplement pellets/BarsLeaks "golden seal" powder (installed in the radiator hose not the surge tank) and drive it. Keep it full of coolant and it will be fine. I have heard of one Northstar in particular with symptoms like you describe going 100,000 miles after the symptoms started - uses coolant regularily but runs fine. Keeping the system full of the BarsLeaks will help prevent any coolant intrusion into the cylinders when the engine is shut down as the most obvious potential problem is filling a cylinder with coolant and hydrostatically locking it on startup. Rare but could happen if the leak gets bad enough.

caddyjax · #9 (**permalink**) 05-05-04, 11:18 PM

i know im coming into this conversation pretty late, but i just got a 94 eldorado and i have had nothing but cooling issues from (*literally*) day #1.

this is putting it lightly!!!!!!!!!

from what i am reading i should turn of my DIC too...

my temp runs normaol around 199 to 203. i freak out at 226 to 230 and i shut it down at 255.

are you guy telling me that this is normal????

new to problematic caddys. but very willing to stay and endure it for the comfort and driving pleasure od the cadillac style.

anything helps...especially from service reps. HINT..HINT...

Anthony Cipriano · #10 (**permalink**) 05-06-04, 12:59 PM

Quote:

Originally Posted by caddyjax

i know im coming into this conversation pretty late, but i just got a 94 eldorado and i have had nothing but cooling issues from (*literally*) day #1.

this is putting it lightly!!!!!!!!!

from what i am reading i should turn of my DIC too...

my temp runs normaol around 199 to 203. i freak out at 226 to 230 and i shut it down at 255.

are you guy telling me that this is normal????

new to problematic caddys. but very willing to stay and endure it for the comfort and driving pleasure od the cadillac style.

anything helps...especially from service reps. HINT..HINT...

No. 255 isn't normal. The system can go to 255 and not boil due to the 50/50 coolant/water concentration and the 15psi pressure cap on the system, but 255 regularily is not normal. Seeing 225-230 is really no need to freak out as those temperatures are common and normal. But 255 is getting to the range that if you are commonly seeing it something is wrong.

Don't know what work or diagnosis has been done to the system but something needs to be done before it erupts completely. Have you replaced the coolant every 2-3 years/24-32k miles? The conventional green coolant in your system needs regular replacement to keep the system fresh and protected from corrosion. The corrosion inhibitors in the system become depleted beyond that service interval and internal engine damage can result, ie head gaskets.

Check the coolant strength carefully with a refractor style tester. If the system is not charged with 50/50 coolant/distilled water that could be causing an overtemp problem due to premature boiling of the system.

Check the water pump drive belt and tensioner. On a 94 the water pump belt is likely worn and the tensioner may be frozen in position such that the water pump is not being driven correctly ie it's slipping. The water pump drive belt is on the rear of the engine on the left side of the engine (front side). It is driven by a small belt that is separate from the main serpentine system on the front of the engine. Make sure the belt is good and that the tensioner is moving freely. Exercise the tensioner and lube the pivot point to make sure it is working correctly.

If it is the original thermostat you might consider a replacement. After 10years/100,000 miles the thermostat doesn't owe you anything and should be considered a normal maintenance item. They do "wear out" and lose their effectiveness.

If the cooling system has not been maintained regularly with fresh coolant there may be clogging of the system due to deposits and gelled coolant (old coolant tends to gel due to silicates parcipitating out of solution). Draining and refreshing with fresh coolant may help.

caddyjax · #11 (**permalink**) 05-06-04, 11:11 PM

thanks for the advice. i was concerned very much with 255 degrees , so i shut it down and bite the bullet of a tow truck. glad i did.

since then i found a leaking radiator end cap and had it replaced. also the thermostat was replaced and a new 15 lb cap. since then it still runs around 196 to 207 (ish). is this normal running temp?

car has 80k on it and is pretty decent other than little things popping up and noyt working temporarily. ??got me? the alternator , im told is going out, so i an contributing many things to that.

i have a knock up front that sounds like a bad strut. the dealer tells me $858 for a ONE (1). WHOOOHHH. now the local advance auto parts tells me they can get one for a 93 eldorado for (get this) $75. but the listing for a 94 is not available (says "see paper catalog"). whats the difference of 93 to 94? this car is not a ETC. can i get away with the 93 strut???

im not trying to be cheap, but $7?? difference is nothing to sneeze at...right?

anyway, im glad i found you guys. hope i learn enuff in a short period of time to help someone else.
thank you all.

RLLOVETT · #12 (**permalink**) 05-07-04, 01:04 AM

Try these guys for the passive (cheap) strut replacement: http://www.arnottindustries.com/products/index.asp

Don97 · #13 (**permalink**) 05-08-04, 07:29 PM

I just bought a 97 D'elegance and I was concerned about temp also but you made me feel better. Would you know if I have any opinions on my other problem. I need a remote (#2 remote) for factory system?

Lawrence · #14 (**permalink**) 05-10-04, 04:25 AM

Quote:

Originally Posted by Don97

I just bought a 97 D'elegance and I was concerned about temp also but you made me feel better. Would you know if I have any opinions on my other problem. I need a remote (#2 remote) for factory system?

"options"?

You can go to the dealer, or try ebay. There usually a lot of them there.

Lawrence · #15 (**permalink**) 05-10-04, 04:26 AM

Quote:

Originally Posted by caddyjax

thanks for the advice. i was concerned very much with 255 degrees , so i shut it down and bite the bullet of a tow truck. glad i did.

since then i found a leaking radiator end cap and had it replaced. also the thermostat was replaced and a new 15 lb cap. since then it still runs around 196 to 207 (ish). is this normal running temp?

car has 80k on it and is pretty decent other than little things popping up and noyt working temporarily. ??got me? the alternator , im told is going out, so i an contributing many things to that.

i have a knock up front that sounds like a bad strut. the dealer tells me $858 for a ONE (1). WHOOOHHH. now the local advance auto parts tells me they can get one for a 93 eldorado for (get this) $75. but the listing for a 94 is not available (says "see paper catalog"). whats the difference of 93 to 94? this car is not a ETC. can i get away with the 93 strut???

im not trying to be cheap, but $7?? difference is nothing to sneeze at...right?

anyway, im glad i found you guys. hope i learn enuff in a short period of time to help someone else.
thank you all.

If you go aftermarket you'll need to replace them in pairs, front or back.