Highway vs. City Eng Temps question
#21
08-15-2018, 06:37 AM
The reason you run hotter on the highway is because the truck is programmed to run close looped during partial throttle/cruising on the lean side for mileage. When your in stop and go, moderate to heavy acceleration or at idle your in open loop mode running mildly rich which cools the engine not to mention your condenser/auxiliary fan is on with a certain intake air temp or coolant temp which ever comes first. This is from the rave manual and for the 1999 to 03/04 model year I believe
#22
08-15-2018, 06:47 AM
Basically what I’m saying is it runs on computer tables when you not cruising and sitting at every light with the a/c on too. Computer programming tends to err on the rich side to compensate for elevated idle temperatures from what I’ve found on most cars. The system turns on the auxiliary fan around 149 degrees intake air temperature or when coolant hits 210 degrees and turns off at 202 degrees. On my truck the engine bay is scalding hot and it’s 110 degrees outside so I know it’s air temp in the intake triggering my fan to engage. When cruising it takes in data from the oxygen sensors and other sensor parameters.
#23
08-15-2018, 09:51 AM
TReK
Hey folks!
Long time reader, first time poster - so cut me some slack
I need everyone's opinion on my Hwy vs Stop-n-Go temperatures. Currently, I'm getting 186f - 194f in the city, including long idles, hot days, stop and go, etc etc. Never budges above 197, ever. The confusing part is that on the Highway I'll sit in the 199f - 207f range, usually around 207f at ~70 mph, or around 2,500 rpm's. I'm wondering why my temperatures are increasing over the highway here? Especially considering how I usually sit in the upper 80's / low 90's driving around town, in the summer. Any ideas I can look into?
I've pretty much re-built the cooling system here at 142k miles:
-New hoses throughout
-New Nissans radiator
-New 180deg thermostat
-New water pump
-Completely flushed old coolant, running roughly 60 / 40 ratio water / coolant + water wetter
-New expansion tank
-OEM fan, but viscous clutch seems to be fine, works like it should
-No obvious air way blockages across the grill
Disco 2 is a 2004, around 143k miles. Any ideas on why my temps are going up so much over the highway? Seems like every thread people mention their hwy temps being lower than city / stop and go, so I'm confused here. Not sure if this matters, but my throttle body heater plate is bypassed. Thanks and much appreciated!
Long time reader, first time poster - so cut me some slack
I need everyone's opinion on my Hwy vs Stop-n-Go temperatures. Currently, I'm getting 186f - 194f in the city, including long idles, hot days, stop and go, etc etc. Never budges above 197, ever. The confusing part is that on the Highway I'll sit in the 199f - 207f range, usually around 207f at ~70 mph, or around 2,500 rpm's. I'm wondering why my temperatures are increasing over the highway here? Especially considering how I usually sit in the upper 80's / low 90's driving around town, in the summer. Any ideas I can look into?
I've pretty much re-built the cooling system here at 142k miles:
-New hoses throughout
-New Nissans radiator
-New 180deg thermostat
-New water pump
-Completely flushed old coolant, running roughly 60 / 40 ratio water / coolant + water wetter
-New expansion tank
-OEM fan, but viscous clutch seems to be fine, works like it should
-No obvious air way blockages across the grill
Disco 2 is a 2004, around 143k miles. Any ideas on why my temps are going up so much over the highway? Seems like every thread people mention their hwy temps being lower than city / stop and go, so I'm confused here. Not sure if this matters, but my throttle body heater plate is bypassed. Thanks and much appreciated!
The Cooling System sounds square, but have you cleaned the condenser? Have you checked in the Auxiliary fan is running?
#24
08-15-2018, 10:14 AM
Finally had a chance to do some hot weather driving with the new cooling system and electric fan... Found the same result, over 80 degrees F and 70mph temps went up. Usually 188 on the highway, under these conditions a steady 194.
Interestingly as I was driving from South to North a distance of 200 miles the outside temps dropped by 10 degrees so I could watch the coolant temp drop back down as the outside air temp decreased from 87 to 77.
Flex-a-lite 300 cfm fan and controller seems to perfectly emulate the OG factory design... for better or worse...
Interestingly as I was driving from South to North a distance of 200 miles the outside temps dropped by 10 degrees so I could watch the coolant temp drop back down as the outside air temp decreased from 87 to 77.
Flex-a-lite 300 cfm fan and controller seems to perfectly emulate the OG factory design... for better or worse...
#25
08-15-2018, 12:26 PM
TReK
Finally had a chance to do some hot weather driving with the new cooling system and electric fan... Found the same result, over 80 degrees F and 70mph temps went up. Usually 188 on the highway, under these conditions a steady 194.
Interestingly as I was driving from South to North a distance of 200 miles the outside temps dropped by 10 degrees so I could watch the coolant temp drop back down as the outside air temp decreased from 87 to 77.
Flex-a-lite 300 cfm fan and controller seems to perfectly emulate the OG factory design... for better or worse...
Interestingly as I was driving from South to North a distance of 200 miles the outside temps dropped by 10 degrees so I could watch the coolant temp drop back down as the outside air temp decreased from 87 to 77.
Flex-a-lite 300 cfm fan and controller seems to perfectly emulate the OG factory design... for better or worse...
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