I know the reason why the "Avoid overheating, turn off A/C next xx miles" signs were put up in the first place, but does anyone know why state DOTs keep replacing them instead of removing them?
CalTrans most prominently has the signs on I-10 between Coachella (https://goo.gl/maps/7ERBvsYJUuKcubMp9) and Cactus City as well as on I-8 near Mountain Spring (https://goo.gl/maps/CfB6nQK9taY6vB8v5). There are a few similar signs installed by NDOT in Nevada.
With modern vehicles, overheating from running the air conditioner is basically a non-issue. Seeing that antiquated sign confuses drivers and can lead them to disregard other yellow warning signs since this one is irrelevant today. In electric vehicles, the A/C compressor runs automatically to cool the battery when needed, so you can't even "obey" the sign and truly turn off the A/C compressor in EVs.
Why is CalTrans spending money to replace these signs when they are worn out instead of just removing them altogether? It is nostalgia? Or perhaps CalTrans wanting to protect themselves from frivolous lawsuits?
I still see cars overheating on my travels. I won't buy a car that doesn't have a temp gauge.
Anyway, from the steaming engines out there I've seen, the signs may still be warranted.
I see cars overheat all the time in on high incline grades in California. In fact I can't recall the last time I didn't see a stalled out car on shoulder along the uphill climb on I-5 south through Grapevine Canyon. I also smell cars not heeding "use low gear" on heavy decline grades way far more often than I'd like.
Quote from: jtespi on August 09, 2022, 05:04:45 AM
I know the reason why the "Avoid overheating, turn off A/C next xx miles" signs were put up in the first place, but does anyone know why state DOTs keep replacing them instead of removing them?
CalTrans most prominently has the signs on I-10 between Coachella (https://goo.gl/maps/7ERBvsYJUuKcubMp9) and Cactus City as well as on I-8 near Mountain Spring (https://goo.gl/maps/CfB6nQK9taY6vB8v5). There are a few similar signs installed by NDOT in Nevada.
I can't recall having ever seen such a sign in Nevada. Can you point to an example?
Quote from: jtespi on August 09, 2022, 05:04:45 AM
I know the reason why the "Avoid overheating, turn off A/C next xx miles" signs were put up in the first place, but does anyone know why state DOTs keep replacing them instead of removing them?
CalTrans most prominently has the signs on I-10 between Coachella (https://goo.gl/maps/7ERBvsYJUuKcubMp9) and Cactus City as well as on I-8 near Mountain Spring (https://goo.gl/maps/CfB6nQK9taY6vB8v5). There are a few similar signs installed by NDOT in Nevada.
With modern vehicles, overheating from running the air conditioner is basically a non-issue. Seeing that antiquated sign confuses drivers and can lead them to disregard other yellow warning signs since this one is irrelevant today. In electric vehicles, the A/C compressor runs automatically to cool the battery when needed, so you can't even "obey" the sign and truly turn off the A/C compressor in EVs.
Why is CalTrans spending money to replace these signs when they are worn out instead of just removing them altogether? It is nostalgia? Or perhaps CalTrans wanting to protect themselves from frivolous lawsuits?
This assumes a well-maintained modern vehicle. As others have noted, I still often see people pulled over with overheated vehicles spewing steam on long inclines. Some are just very old vehicles with weak cooling, but others are more modern vehicles that probably are suffering from a lack of maintenance.
Quote from: roadfro on August 09, 2022, 12:19:36 PM
Quote from: jtespi on August 09, 2022, 05:04:45 AM
There are a few similar signs installed by NDOT in Nevada.
I can't recall having ever seen such a sign in Nevada. Can you point to an example?
Sorry, I don't have a specific example of one of those Nevada signs on GSV, but I found this site (https://www.camaroz28.com/forums/f-body-lounge-24/turn-off-your-air-conditioning-nevada-highways-474840/) that discusses it. That site was one of the few search results that came up on Google when I searched for the wording of the sign. It's personal anecdotes so it might not be accurate. The sign they saw might actually be at the Baker grade on I-15 just a few miles on the California side of the CA/NV state line.
Quote from: Max Rockatansky on August 09, 2022, 08:01:33 AM
I see cars overheat all the time in on high incline grades in California. In fact I can't recall the last time I didn't see a stalled out car on shoulder along the uphill climb on I-5 south through Grapevine Canyon.
Quote from: jdbx on August 09, 2022, 02:38:58 PM
This assumes a well-maintained modern vehicle. As others have noted, I still often see people pulled over with overheated vehicles spewing steam on long inclines. Some are just very old vehicles with weak cooling, but others are more modern vehicles that probably are suffering from a lack of maintenance.
Maybe the presence of the signs are warranted solely due to a small but sizeable portion of the CA population owning cars with questionable reliability and/or maintenance. But I guess for the >95% of drivers with a reliable car, they can ignore the "turn off A/C" warning signs. Out of California's 14.2 million (https://www.statista.com/statistics/196010/total-number-of-registered-automobiles-in-the-us-by-state/) registered cars, 5% would be 710 000.
Is there an issue with having signs that provide practical advice to the unwise driver?
CA-17 south has one specifically to turn off A/C to "prevent boil-over" somewhere between CA 9 and the Santa Cruz county border/Patchen Pass. The sign was there 5-10 years, not sure about today.
Quote from: Max Rockatansky on August 09, 2022, 08:25:59 PM
Is there an issue with having signs that provide practical advice to the unwise driver?
Well like I said in the OP, I think having warning signs that are woefully irrelevant to most drivers can lead them to ignore other similar looking warning signs. They can get de-sensitized to all rectangular warning signs, which are usually longer worded and non-standard (compared to the MUTCD W series warning signs).
Quote from: jtespi on August 10, 2022, 05:58:20 AM
Quote from: Max Rockatansky on August 09, 2022, 08:25:59 PM
Is there an issue with having signs that provide practical advice to the unwise driver?
Well like I said in the OP, I think having warning signs that are woefully irrelevant to most drivers can lead them to ignore other similar looking warning signs. They can get de-sensitized to all rectangular warning signs, which are usually longer worded and non-standard (compared to the MUTCD W series warning signs).
I think you're greatly overestimated the condition the eventual condition of the average car and the skill of the average driver. You're also way over estimating how much people in general likely pay attention to signage given you are MUTCD references.
Quote from: Max Rockatansky on August 10, 2022, 08:22:46 AM
Quote from: jtespi on August 10, 2022, 05:58:20 AM
Quote from: Max Rockatansky on August 09, 2022, 08:25:59 PM
Is there an issue with having signs that provide practical advice to the unwise driver?
Well like I said in the OP, I think having warning signs that are woefully irrelevant to most drivers can lead them to ignore other similar looking warning signs. They can get de-sensitized to all rectangular warning signs, which are usually longer worded and non-standard (compared to the MUTCD W series warning signs).
I think you're greatly overestimated the condition the eventual condition of the average car and the skill of the average driver. You're also way over estimating how much people in general likely pay attention to signage given you are MUTCD references.
Agreed. We pass by many signs on every road which are directed at drivers of large trucks, even though large trucks are rarely a majority of the traffic on a route. I actually enjoy some of the signs, since they are uniquely something I see in California, and they sometimes even use colloquial language, like this one along I-80: (https://i.imgur.com/ExGpts3.jpeg)
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting
too overheated, even in the summer heat.
My family drove to California in June 1968. Being from Wisconsin, we didn't have air conditioning in our car back then. I remember the family 1967 Impala overheating and having to stop at the summit as we entered California on I-15; it was about the 12th of June. The rest area was filled with overheated cars, many in worse shape than ours. A week later we started driving back using I-8 from San Diego, crossing that bit of the Sonoran Desert, again without AC. So yes, you can survive without being too overheated even when it's over 110°F outside.
I think it's often underestimated just how much hill climbing stresses even a modern car designed with adequate cooling capacity. Problems can ensue if the radiator fan isn't working, the pressure cap opens at less than its rated value, the engine is running low on oil (often as a result of the quite high levels of oil consumption manufacturers declare tolerable these days), or the cooling system has lost coolant from evaporation through the surge tank. So while I find it questionable that Caltrans posts "Turn Off A/C" signs even for mild grades like the Grapevine's 5% when Colorado DOT does not use such signing even with much steeper grades, I understand the motivation.
This is a bit like the divide between states that post "Bridge Freezes Before Road" and the ones that don't.
Quote from: J N Winkler on August 11, 2022, 04:16:32 PM
I think it's often underestimated just how much hill climbing stresses even a modern car designed with adequate cooling capacity.
So while I find it questionable that Caltrans posts "Turn Off A/C" signs even for mild grades like the Grapevine's 5% when Colorado DOT does not use such signing even with much steeper grades, I understand the motivation.
Yeah I find it very odd because I haven't seen "Turn Off A/C" signs in other states. I'll just chalk it up to a California oddity just like those "55 MPH Max When Towing" signs. Although, I have more respect for the latter since towing is statistically more dangerous than regular driving.
The Rocky Mountain states have more demanding elevation grades and yet don't post those silly "Turn Off A/C" signs.
Quote from: J N Winkler on August 11, 2022, 04:16:32 PM
This is a bit like the divide between states that post "Bridge Freezes Before Road" and the ones that don't.
Oh yeah, when you are driving in states in the South (especially Texas) those signs are overdone. Texas literally posts them at every single bridge. You get desensitized to them after a few hours of driving. I wish TxDOT and other state DOTs that use the "bridge ices" signs would use a variant of the Canadian sign (https://commons.wikimedia.org/wiki/File:CA-QC_road_sign_D-320.svg).
I could have sworn that I saw a version where once it hits 0°C, the sign displays a blue snowflake to let you know that is it below freezing. However, I can't find it anywhere online. It would use similar technology to IceAlert (https://www.icealert.com/ice-alert).
Just saw this A/C warning sign in Washington of all places on a trip this past weekend: https://goo.gl/maps/jqjTkj9Gotc77vr59. Seems like the common theme here might be desert climbs as this one is in Central Washington and all the California examples that I know of are in desert areas in the south. Does anybody know if Arizona has posted any signs like this? Perhaps on I-17's big climb between Phoenix and Flagstaff.
Quote from: jtespi on August 13, 2022, 01:40:18 AM
I could have sworn that I saw a version where once it hits 0°C, the sign displays a blue snowflake to let you know that is it below freezing. However, I can't find it anywhere online. It would use similar technology to IceAlert (https://www.icealert.com/ice-alert).
Those definitely exist. I've seen them too, though I can't find one off the top of my head. All the ones I've seen have just been on local streets.
Quote from: skluth on August 11, 2022, 02:18:05 PM
My family drove to California in June 1968. Being from Wisconsin, we didn't have air conditioning in our car back then. I remember the family 1967 Impala overheating and having to stop at the summit as we entered California on I-15; it was about the 12th of June. The rest area was filled with overheated cars, many in worse shape than ours. A week later we started driving back using I-8 from San Diego, crossing that bit of the Sonoran Desert, again without AC. So yes, you can survive without being too overheated even when it's over 110°F outside.
My parents and I took a similar trip roughly a year before yours. Our 1966 Buick Special did not come with A/C, but we had an add-on unit installed prior to the trip. However, the factory radiator fan was not modified. That was not a problem here in the flat topography of Indiana, or even through the Rockies in Colorado, but when we hit the Grapevine grade upon departing California's Central Valley, we overheated less than a quarter mile before the old water stop that was there just for travelers who had the same problem along that roadway. On the way back from Ventura, we overheated several more times, the worst just after departing Barstow on I-15 heading to Vegas. But we luckily found a place to safely cross the median and coast back down the hill to town for repairs.
By the way, Arizona also still has one of the signed mentioned in this thread on I-17, heading north from Phoenix to Flagstaff, at least as of a couple of years ago.
If Nevada has them, they certainly aren't along I-80, as I have driven the entire length of it in Nevada in the past month and a half.
Quote from: stevashe on August 18, 2022, 02:36:38 PM
Quote from: jtespi on August 13, 2022, 01:40:18 AM
I could have sworn that I saw a version where once it hits 0°C, the sign displays a blue snowflake to let you know that is it below freezing. However, I can't find it anywhere online. It would use similar technology to IceAlert (https://www.icealert.com/ice-alert).
Those definitely exist. I've seen them too, though I can't find one off the top of my head. All the ones I've seen have just been on local streets.
There are a few of these in the Northeast. Vermont has them on the US 4 expressway (https://goo.gl/maps/ouqp5sh4j5YhFQzY6) west of Rutland.
Quote from: Scott5114 on August 10, 2022, 09:26:25 PM
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting too overheated, even in the summer heat.
As long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Quote from: jeffandnicole on September 03, 2022, 11:44:28 PM
Quote from: Scott5114 on August 10, 2022, 09:26:25 PM
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting too overheated, even in the summer heat.
As long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Speaking as someone who just drove across the country in a car without working A/C, it's doable. Didn't even have the fan going for a lot of it. Lots of fluids, stops to see things/get out of the hot car, wet towel for the hottest day. Do I want to do it again? Not really, but people drove in the summer without A/C before cars routinely had it.
Quote from: cl94 on September 04, 2022, 05:28:18 PM
Quote from: jeffandnicole on September 03, 2022, 11:44:28 PM
Quote from: Scott5114 on August 10, 2022, 09:26:25 PM
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting too overheated, even in the summer heat.
As long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Speaking as someone who just drove across the country in a car without working A/C, it's doable. Didn't even have the fan going for a lot of it. Lots of fluids, stops to see things/get out of the hot car, wet towel for the hottest day. Do I want to do it again? Not really, but people drove in the summer without A/C before cars routinely had it.
My wife did it for about a month last summer when the A/C fan clutch broke on her Forester. She used a USB powered fan and rolled her windows down partially on CA 99. She claimed it was fine driving back and forth to work from Fresno-Madera like that.
Quote from: cl94 on September 04, 2022, 05:28:18 PM
Quote from: jeffandnicole on September 03, 2022, 11:44:28 PM
Quote from: Scott5114 on August 10, 2022, 09:26:25 PM
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting too overheated, even in the summer heat.
As long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Speaking as someone who just drove across the country in a car without working A/C, it's doable. Didn't even have the fan going for a lot of it. Lots of fluids, stops to see things/get out of the hot car, wet towel for the hottest day. Do I want to do it again? Not really, but people drove in the summer without A/C before cars routinely had it.
Obviously, our parents and grandparents all did without things we have now. Many houses didn't have air conditioning...nor window units. A/C, cellphones, interstate highways didnt exist. Even basic things like the ATM is really not that old of a convenience...50 years ago there was no impromptu road trips if someone didn't have money or travelers checks laying around the house. You weren't stopping to get money on a Sunday...and generally a Saturday. If you were lucky to have a Visa or Mastercard, chances are gas stations didn't take it anyway. When people took Sunday drives, they were usually pretty local. Nothing like what we do today at the spur of the moment.
Quote from: jeffandnicole on September 04, 2022, 07:05:53 PM
Quote from: cl94 on September 04, 2022, 05:28:18 PM
Quote from: jeffandnicole on September 03, 2022, 11:44:28 PM
Quote from: Scott5114 on August 10, 2022, 09:26:25 PM
Quote from: pderocco on August 10, 2022, 08:05:32 PM
They should say "Avoid overheating engine, turn off A/C next xx miles". This pretty much guarantees overheating the passengers.
Well, I mean, 10 miles at 70 MPH is, what, 8½ minutes? I think I can go without A/C for that long without getting too overheated, even in the summer heat.
As long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Speaking as someone who just drove across the country in a car without working A/C, it's doable. Didn't even have the fan going for a lot of it. Lots of fluids, stops to see things/get out of the hot car, wet towel for the hottest day. Do I want to do it again? Not really, but people drove in the summer without A/C before cars routinely had it.
Obviously, our parents and grandparents all did without things we have now. Many houses didn't have air conditioning...nor window units. A/C, cellphones, interstate highways didnt exist. Even basic things like the ATM is really not that old of a convenience...50 years ago there was no impromptu road trips if someone didn't have money or travelers checks laying around the house. You weren't stopping to get money on a Sunday...and generally a Saturday. If you were lucky to have a Visa or Mastercard, chances are gas stations didn't take it anyway. When people took Sunday drives, they were usually pretty local. Nothing like what we do today at the spur of the moment.
Several oil companies had their own cards. I was surprised I could get an Amoco card in college, even though my only obvious income was a weekend hotel job. I think it had a limit of about $500, but it was fine for getting around town and even short trips when gas was about $1/gallon. But I remember my parents always stocking up on cash and travelers checks before a big vacation, usually after cashing some savings bonds. It wasn't a problem when we went camping in the UP as the campground and even the local grocery would take my mom's check.
All those vacations were without the benefit of car AC as my parents didn't have a car with AC until after I graduated HS. But AC wasn't an issue in Wisconsin.
Quote from: jeffandnicole on September 03, 2022, 11:44:28 PMAs long as you have a fan on, you may be ok. But with the sun roasting in a car, it can get awfully hot awfully fast.
Quote from: cl94 on September 04, 2022, 05:28:18 PMSpeaking as someone who just drove across the country in a car without working A/C, it's doable. Didn't even have the fan going for a lot of it. Lots of fluids, stops to see things/get out of the hot car, wet towel for the hottest day. Do I want to do it again? Not really, but people drove in the summer without A/C before cars routinely had it.
Quote from: Max Rockatansky on September 04, 2022, 05:36:16 PMMy wife did it for about a month last summer when the A/C fan clutch broke on her Forester. She used a USB powered fan and rolled her windows down partially on CA 99. She claimed it was fine driving back and forth to work from Fresno-Madera like that.
I have done multiple desert crossings in the summertime (including I-8 from San Diego to I-10 in September) with blower fan at top speed, windows rolled up all the way, and no A/C. With cold water (I had a Coleman gallon jug with a drinking spout that I could fill with ice and then water) and no passengers (so the driver can monopolize airflow through the vents), it is eminently doable and the penalty in terms of comfort is not severe. This said, I emphatically do
not recommend doing this in a car that has working A/C:
* Once the car interior has cooled down and the A/C is running in recirculating mode, the savings in fuel are negligible.
* The driver still sweats enough to leave visible salt crusts on dark clothing and to shift dyes in clothes, leather goods such as belts, and car seat fabric. You can literally ruin a good shirt doing this.
I have a separate set of clothes I call a "sweat suit" (in quotes since it is not the same as an actual sweatsuit, track suit, shell suit, etc.) that I wear for long drives in the heat. It consists of white trousers worn without a belt, a white T-shirt, and a long-sleeved breathable light yellow sportfisher's shirt. The neck-to-ankle fabric coverage avoids direct contact between sweaty skin and seating surfaces. The second layer on top keeps my left arm from browning in the sun and provides an additional barrier between my skin and the seatback.
I'd even go so far as to recommend that any shirt worn to drive without A/C should be cut generously through the shoulders. If it is tight there, it takes just a few hours to start stinking of apocrine sweat, and over time it picks up gray stains that don't wash out.
Quote from: jeffandnicole on September 04, 2022, 07:05:53 PMMany houses didn't have air conditioning...nor window units.
In the old days, before window A/C and central A/C became the norm, houses were often fitted with swamp coolers even in areas (such as Wichita) where they don't work well because of high humidity in the summertime. Proper refrigerant-based A/C that dehumidifies as well as cools is a true blessing.
Quote from: J N Winkler on August 11, 2022, 04:16:32 PM
Problems can ensue if the radiator fan isn't working ...
This. A few years ago, my best friend's vehicle overheated in Mexico. It's a 2005 Nissan Pathfinder (one of those "modern vehicles"), and he constantly does his own maintenance and parts replacements. It ended up that the engine block cracked from the overheating, and he had to have the engine replaced (with a 2012 Nissan Xterra engine). After it happened, he started thinking back, and he realized it had been a while since he'd heard the radiator fan kick on, so he suspects that may have been at least a contributing factor. That fan not kicking surely wasn't due to lack of regular maintenance, and I'd be willing to bet that the large majority of drivers neither realize there are two fans under the hood nor listen for them.
"Speed enforced by aircraft" . On CA-25. In San Benito County. Because sure, San Benito County has the time, money, and aircraft to patrol that remarkably rural road.
Quote from: jander on September 12, 2022, 10:23:03 PM
"Speed enforced by aircraft" . On CA-25. In San Benito County. Because sure, San Benito County has the time, money, and aircraft to patrol that remarkably rural road.
At least trying to maintain 55 MPH or higher is actually kind of a challenge (a fun one) on 25 from 198 to J1.
Quote from: jander on September 12, 2022, 10:23:03 PM
"Speed enforced by aircraft" . On CA-25. In San Benito County. Because sure, San Benito County has the time, money, and aircraft to patrol that remarkably rural road.
I saw those signs growing up in rural Kansas. Are/were they not a nationwide phenomenon?
Quote from: kphoger on September 13, 2022, 09:49:52 AM
Quote from: jander on September 12, 2022, 10:23:03 PM
"Speed enforced by aircraft" . On CA-25. In San Benito County. Because sure, San Benito County has the time, money, and aircraft to patrol that remarkably rural road.
I saw those signs growing up in rural Kansas. Are/were they not a nationwide phenomenon?
It's a dig at how silly the expense of wasting money on such a rural and lightly traveled state highway would be. 25 would be high on the list of my favorite desolate state routes, very scenic but you are on your own. Amusingly 25 is called the Airline Highway.
Quote from: kphoger on September 06, 2022, 01:49:17 PMThis. A few years ago, my best friend's vehicle overheated in Mexico. It's a 2005 Nissan Pathfinder (one of those "modern vehicles"), and he constantly does his own maintenance and parts replacements. It ended up that the engine block cracked from the overheating, and he had to have the engine replaced (with a 2012 Nissan Xterra engine). After it happened, he started thinking back, and he realized it had been a while since he'd heard the radiator fan kick on, so he suspects that may have been at least a contributing factor. That fan not kicking surely wasn't due to lack of regular maintenance, and I'd be willing to bet that the large majority of drivers neither realize there are two fans under the hood nor listen for them.
This is one reason I get nervous about automakers eliminating temperature gauges (the 2009 Honda Fit in the family fleet doesn't have one).
Most newer cars have "soft start" fans that essentially run only as fast as needed to regulate coolant temperature to within about 10° F of a setpoint just above thermostat opening temperature. To the driver it looks like the needle being pinned to just beneath the center of the gauge once the car is warmed up. Without the ability to hear the fan, it can be hard to tell when the engine is laboring under thermal stress, but if the needle unpins and starts climbing, that is a pretty definite sign of problems.
Older cars, like my Saturn, tend to have "hard start" fans that run at full speed only when coolant temperature gets well above normal (thermostat opening plus ~30° F). When a properly working fan triggers, the gauge needle swings rapidly back toward C until the thermostat is about to close, when the fan cuts out. I have driven the Saturn for years and years without the fan coming on even once, only for it to run multiple times while I wait in traffic to cross the Bay Bridge or try to climb grades on the Pikes Peak toll road in top gear.
Quote from: J N Winkler on September 13, 2022, 01:47:36 PM
This is one reason I get nervous about automakers eliminating temperature gauges (the 2009 Honda Fit in the family fleet doesn't have one).
Most newer cars have "soft start" fans that essentially run only as fast as needed to regulate coolant temperature to within about 10° F of a setpoint just above thermostat opening temperature. To the driver it looks like the needle being pinned to just beneath the center of the gauge once the car is warmed up. Without the ability to hear the fan, it can be hard to tell when the engine is laboring under thermal stress, but if the needle unpins and starts climbing, that is a pretty definite sign of problems.
Older cars, like my Saturn, tend to have "hard start" fans that run at full speed only when coolant temperature gets well above normal (thermostat opening plus ~30° F). When a properly working fan triggers, the gauge needle swings rapidly back toward C until the thermostat is about to close, when the fan cuts out. I have driven the Saturn for years and years without the fan coming on even once, only for it to run multiple times while I wait in traffic to cross the Bay Bridge or try to climb grades on the Pikes Peak toll road in top gear.
Temperature gauges aren't all the same anyway. In the case of the Pathfinder, when that generation first came out in 2005, it had a real temperature gauge whose needle would move as the operating temperature fluctuated. But so many people were taking their car to the mechanic for a supposed cooling system problem, when in fact nothing was wrong, that Nissan started installing a different type of gauge partway through the 2006 model year. In the new gauge (the type both of mine mine had, which I've heard referred to as a "dummy gauge"), once the engine reaches normal operating temperature, the needle just pins to the midway point, no matter how the actual temperature fluctuates, until it reaches a near-critical threshold. That way, people don't start freaking out at every little bump up and down of the needle. In fact, I could often tell I was nearly out of coolant by the vents not blowing very much hot air
well before I ever saw the needle move on the gauge. And thus the downside is apparent: by the time the needle would actually start to move upward, it would reach <H> within seconds, because the situation under the hood was so dire by that point.
Quote from: kphoger on September 13, 2022, 01:58:09 PMTemperature gauges aren't all the same anyway. In the case of the Pathfinder, when that generation first came out in 2005, it had a real temperature gauge whose needle would move as the operating temperature fluctuated. But so many people were taking their car to the mechanic for a supposed cooling system problem, when in fact nothing was wrong, that Nissan started installing a different type of gauge partway through the 2006 model year. In the new gauge (the type both of mine mine had, which I've heard referred to as a "dummy gauge"), once the engine reaches normal operating temperature, the needle just pins to the midway point, no matter how the actual temperature fluctuates, until it reaches a near-critical threshold. That way, people don't start freaking out at every little bump up and down of the needle. In fact, I could often tell I was nearly out of coolant by the vents not blowing very much hot air well before I ever saw the needle move on the gauge. And thus the downside is apparent: by the time the needle would actually start to move upward, it would reach <H> within seconds, because the situation under the hood was so dire by that point.
This is interesting. The first-generation Saturn S-Series had a similar issue in that small temperature changes would produce a lot of needle movement and the fan-on point corresponded to an indication just to the left of the red stripe next to H. (This is the gauge I have.) Many owners panicked, thinking their cars would boil over imminently in traffic. The gauge was redesigned to reduce the amount of needle movement and to reposition the red stripe, but still gave a honest indication of temperature. I can't say I think much of Nissan's approach.