: Cooling Fans



J.A.O.
07-13-06, 05:35 PM
For the most part, most seem to agree that the cooling fans kick on high when the temperature reaches 225. Is there anyone who might know for certain when the fans step back down to low???

Is it just when the temperature falls below 225, or is it after the fans have had the opportunity to bring the temp back down to a cooler temp. If so, what is that temperature??


Thanks fellas.

JimD
07-13-06, 06:02 PM
Different years might show slightly different numbers but this is what I have measured on my '98 Seville.

A/C OFF. Fans come on at low speed at 223 degrees and are powered off at 212 degrees.

Blocking the air flow and power-braking at 1,500 RPM, I got the fans on at high speed at 234 degrees and they stayed at high speed until the temperature dropped to 212 degrees.

krimson_cardnal
07-13-06, 08:20 PM
this will cover 69deville fans [from the shop manual]

http://www.cadillacforums.com/forums/cadillac-deville-1985-2005-including-1985/74293-cooling-fans-engine-temp-air-temp.html?highlight=fans

Ranger
07-13-06, 08:27 PM
Also remember that they are on high anytime the A/C is on so don't let that throw you if you are inspecting it.

J.A.O.
07-13-06, 09:06 PM
Thanks for the input guys. Krimson Cardnal, I checked out your link. That was very interesting. Is there any mention about when the fans will be turned down? My only reason for even starting this post was that yesterday, I was driving in Phoenix and the temp outside was 112. I dropped off a friend and was in stop and go traffic for about 10 min (AC on of course), and the needle went to the last white mark before the red. It has done this before in heavy traffic or at highway speeds in these temps. It comes down slightly but, maybe only 2 needle widths if I'm not accelerating or climbing a grade. Anyway, I got home and turned the AC off, but the fans remained on high for about 2 minutes. When they finally stepped down, the needle was a needle's width to the left of the last white mark on the temp gauge. I was thinking that maybe at least on my gauge, that point marked 225 or maybe something less.

Before anyone asks, the car has been checked and has a clean bill of health. The water pump is fine, the radiator is less than a year old (I had it replaced before I moved out here), the coolant is fine and changed regularly, and the head gaskets are fine. I hope I'm just worried about nothing, but that temp gauge does tend to read higher than most that I've seen. It's done this since the day I bought it 4 years ago and she hasn't overheated on me. But after living in Phoenix for about a year, I find myself staring at the gauge more as the outside temps exceed 110.

Ranger
07-13-06, 09:22 PM
I guess at 112 degrees ambient, you have to give the old girl a little leeway, especially if she has not failed you yet. Have you checked the obvious, drive belt, thermostat & purge line?

krimson_cardnal
07-14-06, 06:48 AM
my guess is they drop from high to low once the high condition to satisfied. they seem to have a lag built in. not a straight foward thing as you can see by the criterial evaluated to run them.

i would not obsess on engine temps. i've seen mine jump around, certainly with this hot weather, though i've not seen 112 ambient here in NY.

sounds like your ride is in good shape - trust it. lots and lots have been posted - search it out. bottom line is your NorthStar knows how to keep its cool... be cool and trust it.

J.A.O.
07-15-06, 06:44 PM
Thanks again for the feedback guys.

GreenMachine
07-16-06, 01:02 PM
One thing I noticed that wil cause my temp to jump is how close I am to other cars in the stop and go. Think about it for a second, on top of that 112 outside temp, your also now letting all the exhaust gas from the car infront vent into your fans and air intake. My general rule of thumb has been stay back enough that you can see bottom of the tires of the car infront of you, or at least the bottom of the bumper. :) Sometimes this doesn't always happen but the next time your in traffic test it out and you'll be surprised how much just being close to another cars rear will make the temps go up in stop and go.


Thanks for the input guys. Krimson Cardnal, I checked out your link. That was very interesting. Is there any mention about when the fans will be turned down? My only reason for even starting this post was that yesterday, I was driving in Phoenix and the temp outside was 112. I dropped off a friend and was in stop and go traffic for about 10 min (AC on of course), and the needle went to the last white mark before the red. It has done this before in heavy traffic or at highway speeds in these temps. It comes down slightly but, maybe only 2 needle widths if I'm not accelerating or climbing a grade. Anyway, I got home and turned the AC off, but the fans remained on high for about 2 minutes. When they finally stepped down, the needle was a needle's width to the left of the last white mark on the temp gauge. I was thinking that maybe at least on my gauge, that point marked 225 or maybe something less.

Before anyone asks, the car has been checked and has a clean bill of health. The water pump is fine, the radiator is less than a year old (I had it replaced before I moved out here), the coolant is fine and changed regularly, and the head gaskets are fine. I hope I'm just worried about nothing, but that temp gauge does tend to read higher than most that I've seen. It's done this since the day I bought it 4 years ago and she hasn't overheated on me. But after living in Phoenix for about a year, I find myself staring at the gauge more as the outside temps exceed 110.

J.A.O.
07-16-06, 03:07 PM
Green Machine,

That's a very good point. I've actually considered that as well. Unfortunately, sometimes traffic doesn't allow us the leverage to keep the spacing we want.

Another thought!!!

My car has a factory oil cooler (about 6 x 8") in front of the condenser on the passenger's side. I know not all the cars have these. Is it possible that that oil cooler could be part of the issue??? I would think that the engine oil would have to be pretty close to 180 - 200 degrees when it passes through there. So instead of 112 degree ambient air passing through the condenser then the radiator over that 6 x 8" area, you have 180 - 200. Is it possible that the system is having a little trouble under such hot ambient conditions keeping up?? I was thinking about it this morning. A friend of mine has a 96 SLS and it doesn't have the oil cooler. Assuming the temp sending units in our cars are both calibrated the same (which I know sometimes they aren't), his needle never goes past the half way point. Now he doesn't live in AZ, but when we both lived in FL, my car did the same thing it does now only that the gage is a little warmer (I assume because of the higher ambient temps).

white97deville
07-18-06, 06:24 PM
JAO.

On my car that oil cooler in front of the condenser is a power steering cooler. Not sure how different our cars are. With all of the 100+ degree days we've been having here in Dallas the temps have been running higher than normal. I'm ready for a cold front to drop us back into the mid 90's....or some rain!

Jonathan