wake Posted August 6, 2005 Report Share Posted August 6, 2005 I'm curious what our resident Caddy/NS expert thinks about this... I just got back from Phoenix where the temps were running from 105-112F across the CA and AZ deserts... One interesting observation I made was that at normal speeds of 75-80 MPH and ~2500 RPM, the temp ran between 225F and 232F with the A/C on at a normal cruise on level ground... When traffic was running fast, 90-95 MPH and ~3000 RPM I noticed that at sustained cruise the coolant temp dropped to 212F-217F... When I slowed back down to 75 MPH, the temp climbed back up to 225F-232F, and when I sped back up to 90 MPH, the temp dropped back to 212F... I did this several times while the outside temp was 105F and each time the car cooled off while running faster... Now I know that the temps aren't hurting anything, but I'm just curios why I'm running cooler in the hot weather when the engine is working harder... I know there's more airflow across the radiator, but the engine is also running harder also... So my question is, is it the water pump that is the limiting factor in our cooling system temp??? What's the bottleneck so to speak, in our cooling system??? Link to comment Share on other sites More sharing options...
Scotty Posted August 6, 2005 Report Share Posted August 6, 2005 This observation is much like an observation that I had. A few months ago I noticed that if I take the car out of OD and put it into D the temps drop, obviously the reason is that the RPM picks up and turns the water pump faster. I believe you are experiencing the same, the RPM increase AND the ram air affect of the higher speed... Link to comment Share on other sites More sharing options...
Ranger Posted August 6, 2005 Report Share Posted August 6, 2005 Recently I had posted that the outside temp was 105 and at 70 MPH I was running 206. It occassionaly went to 210 for a brief period but quickly returned to 206. I think the "bottleneck" and variable in our cars is the thermostat. In winter I will run 213-216. The water pump turns the same RPM as the engine. Link to comment Share on other sites More sharing options...
Scotty Posted August 6, 2005 Report Share Posted August 6, 2005 Recently I had posted that the outside temp was 105 and at 70 MPH I was running 206. It occassionaly went to 210 for a brief period but quickly returned to 206. I think the "bottleneck" and variable in our cars is the thermostat. In winter I will run 213-216. The water pump turns the same RPM as the engine. Man I would love those temps! I have a new OEM stat also and I don't get those coolant temps at 97/98 outside temp... But I am happy, my temps are pretty stable, rarely do I go over 222 and when I do, I get 230 in traffic for a few minutes which I don't mind... Link to comment Share on other sites More sharing options...
Bob D Posted August 6, 2005 Report Share Posted August 6, 2005 Like Scotty was suggesting, I think it's a little more coolant through the motor (rpms spinning H2o pump) and a WHOLE lot more air through the radiator.. My STS at 75 mph, A/C on, outside temp 100, flat road, will typically run about 215 degrees. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
davedog Posted August 6, 2005 Report Share Posted August 6, 2005 I'll throw some more data in the mix: 92 eldo, 78k, 4.9L engine, about 95 degrees out, AC on, around-town driving - I average about 216 - 218 degrees or so. -dave Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k Link to comment Share on other sites More sharing options...
Bob D Posted August 6, 2005 Report Share Posted August 6, 2005 My STS at 75 mph, A/C on, outside temp 100, flat road, will typically run about 215 degrees. (Just gott back from a run down the hill..) 101 degrees out (and it's only noon..jeezzz..)...make that 215-220 degrees, at 75, a/c on, flat highway. 230 on a good hill climb, still at 75.. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
blunted Posted August 6, 2005 Report Share Posted August 6, 2005 Some observations from NYC traffic... 1994 Eldorado 95 degrees, stop and go traffic (lights) with the A/C on at 60 Auto.. the car ranges from 216 up to 234. 234 only happens here and there, I have started getting comfortable with hitting 230-232 at least once a day but it doesnt usually stay there for more than 2-5 minutes. Then it'll come back down to 223-226.. I just dont wanna see 236 anytime soon. If i'm driving at a constant speed on the highway at around 60-90 mph my car runs anywhere from 196-216 regardless of temperature outside. .. A little off topic, but I do WOT at least 1-4 times a week, I cant get enough of that roar with the mufflers I got on her and not to mention the classic expression of people in their BMW's or Mercedes. Should I try to cut down on that since its a 11 year old car?.. I just hit 70K last week. Link to comment Share on other sites More sharing options...
Ranger Posted August 6, 2005 Report Share Posted August 6, 2005 Recently I had posted that the outside temp was 105 and at 70 MPH I was running 206. It occassionaly went to 210 for a brief period but quickly returned to 206. I think the "bottleneck" and variable in our cars is the thermostat. In winter I will run 213-216. The water pump turns the same RPM as the engine. Man I would love those temps! I have a new OEM stat also and I don't get those coolant temps at 97/98 outside temp... But I am happy, my temps are pretty stable, rarely do I go over 222 and when I do, I get 230 in traffic for a few minutes which I don't mind... I just don't get it. Same engine, same components, same coolant and yet vastly different temps. I think it would have to get down to -40 for mine to go 230 based on based on my observations. Link to comment Share on other sites More sharing options...
Scotty Posted August 6, 2005 Report Share Posted August 6, 2005 At 70 I will run 210 to 215 in this kind of heat (+95 degree), so we may be comparable, although at times I will rise to 220. I get the 222 in stop and go around town traffic. Is it possible that my tranny convertor is slipping more than yours and causing more heat? Wouldn't excessive slip by the convertor cause a code? Link to comment Share on other sites More sharing options...
Ranger Posted August 6, 2005 Report Share Posted August 6, 2005 Yeah, I would think if the there was converter slippage you would probably get a VCC solenoid code. You should feel it lock up at 41 MPH if it is working properly. Link to comment Share on other sites More sharing options...
Scotty Posted August 6, 2005 Report Share Posted August 6, 2005 Yeah, I would think if the there was converter slippage you would probably get a VCC solenoid code. You should feel it lock up at 41 MPH if it is working properly. Oh yea I feel it locking up and I feel it releasing when I tap the brake. I thought it could slip when engaged, am a wrong about that? Also I am missing the tarpaper like material in front of my radiator that goes across the front of the car, it was damaged and I removed it, maybe when I replace this (i have a new one) it will help to direct more air through the radiator. Link to comment Share on other sites More sharing options...
Ranger Posted August 7, 2005 Report Share Posted August 7, 2005 I am not sure but I thought there was no slippage when it is locked up. Yeah, I suspect you may see a cooler temp when you replace that material. Let us know. I'd be curious. I suspect that is the reason it is there. Link to comment Share on other sites More sharing options...
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