Car get overheated while ascending hilly area any clue?

[ahmedfaseeh8]

Honda civic 2014 and and honda civic 2018 both car was driven from rawalpindi to shogaran(kaghan valley) in winter and up to kawai the atmosphere temperature was 7c and car temperature was normal.as we car started ascending to shogaran road after 5 to 10 mins car get heat up.i saw the steam flying from bonet we wait hardly 10 minutes and car get cold as outside temperature drop to 3c we fill the water reservoir (because of no spare coolant) and start journey again same thing happened again with in 5 minutes and keep happening and we keep repeating process 4 to 5 times untill we reached shogaran.during return to rawalpindi we haven't get any overheating trouble until now.both cars behave similar way.
Honda civic 2014 vti coolant atlas and gear was on 2 selection during ascending.
Honda civic 2018 coolant gulf gear was L during ascending.
Engine/radiator cooling fan wasn't running during this incident but running before and after when out side temperature was increase.mechinc told us fan only runs when the detect higher temp because the ambient temperature was so low that temperature prevent fan to run automatically is it true?some said counterfeit engine oil could be behind overheating i use honda genuine oil.what u guys think about possible cause of overheating?

[chinyoti]

This is pretty normal where oxygen is less.

Don't worry. Just get your cooling system double checked for assurance.

Auto fan and thermostat working or not.

[aminjafer5441]

You didn't mention if the temperature needle on the odometer was in the hot range. The scenario you are describing is 99% a faulty radiator cap. The cap is supposed to keep the cooling system under a certain amount of pressure usually mentioned on the cap itself. There is a noticeable difference in atmospheric pressure at Shogran and places at such heights. Whenever the atmospheric pressure decreases, the pressure inside the cooling system can overwhelm the spring in the radiator cap hence causing the coolant/water to boil and escape as steam.
Also when ascending, it is no surprise that the engine is generating a lot of heat and any weak spots in the cooling system would surface at this point.
I came to this conclusion because you mentioned that the radiator fan(s) didn't kick in even when the coolant was boiling over and steam was coming from under the bonnet. This is a basic physics principle where when external pressure (in this case atmospheric pressure) is reduced, it becomes much easier for any liquid to boil over at a lower temperature.
Had your car been overheating, the fan(s) would have turned on first and temp gauge would have warned you.

[sardarg]

sir @aminjafer5441 radiator cap need to be replaced. Ambient temp has no equation with engine temp if a working thermostat valve & functional radiator cap are in place. The cluster gauge functioned correct showing climb & normal, right so the ambient temp story stands null & void.

[pwuser150504674948]

1. Change your mechanic
2. Fan will turn on if coolant temperature rises doesnt matter if ambient temperature is -50 degrees
3. Faulty radiator cap/weak hoses/leaky radiator will all cause coolant escape under pressure
4. Get the cooling system pressure checked by a professional, replace old hard hoses, get the cooling fan checked (it should have been running full speed in the scenario you mentioned) and use genuine coolant.
5. Was the car overloaded? Were you trying to speed up or race each other because that road is a pretty steep climb. lve seen similar scenarios on chilas babusar climb people tend to speed up and stress the engine and end up overheating the car. New or old car doesnt matter there.

[chinyoti]

Ambient temperature might not, Less Oxygen can cause the thermostat needle to rise.

[darthvader]

what are you talking about man. steam coming from an engine is not normal under any circumstances. and shogran is barely 7500-8000ft above sea level

[daniyalcars72]

im pretty sure your coolant would freeze at -50 ..although this theory that ambient temp aka outside temperature doesnt matter isnt fully true as ambient temp plays a big rule in regulating engine temperature this is one of the reason you dont notice the radiator fan turning on when the car is in motion 60km/hr plus speeds ..and in winter times even at idle it takes longer idling times for the radiator fan to turn on and that to when in traffic or idling for long time , unless your whole cooling system is wrecked ambient temp also matters .

[hash4u]

disagree with everyone above
you can repeat the exact same trip
drive uphil in D and nothing will happen
Low gears are for downhill.
a wise @ss colleage overheated almost brand new car as he kept driving uphill on salt range in S mode

[aminjafer5441]

Umm, care to explain why all above suggestions are invalid?
Clearly the cars ecu was not registering a high enough coolant temp to engage to the cooling fans and yet coolant was leaking/escaping. The most likely scenario that can cause this, is a weakness in the cooling system like the radiator cap not holding in the pressure or a hose etc that is giving under pressure.
Since OP is not facing any issue when back in rwp/islamabad where atmospheric pressure is much higher and actually helps/assist the cap and cooling system to hold the pressure.
About using L(low) gear or S (sport) when ascending, this is the first time that I'm hearing that it is only for down hill and not going uphill.
Both of these options should ideally hold a lower gear for longer and keep the transmission and engine more responsive? I maybe wrong, but is there any factual information that states only D gear to be used when ascending ?

[aminjafer5441]

ambient temp does matter but at 7 degrees celcius no car would ever overheat if the cooling system is in optimal condition.
While lower ambient temp would increase the warm up time for an engine it would never change the coolant temperature at which the thermostat valve opens or at which the radiator fans turn on.
Most cars I've kept have the thermostat open at 82-87 degrees celcius of coolant temp, and the cooling fans kick in at 98 degrees. In cold weather, while the car is moving, the airflow through the radiator is enough to keep the engine coolant from ever reaching 98 degrees hence the fans almost never turn on.
In this case, the fans never came on and still the the coolant boiled/leaked hence the lower ameint temperature probably has nothing to do with this specific issue.

[pwuser150504674948]

Please read the post again.
If the engine coolant temperature RISES the cooling fans which get signal from the coolant temperature sensor will turn on even if you are in Antartica.

Sure driving at 60kmph or in cold weather is sometimes enough to cool the coolant passing through the radiator without the need of a fan when the engine is not under undue stress. It all depends on coolant temperature.

Steam as described by OP clearly shows the coolant temperature was way above normal causing pressure to build and leak and in this case fans should have been blowing at full speed. His mechanic is totally wrong by stating that fans dont kick in at cold temperatures.

[pwuser150504674948]

Car will overheat in D mode also if you start racing and reving uphill and put constant stress on engine.

Whereas keeping the Rpms within 3000 mark even in S mode will never heat up the car with an error free cooling system.

[haseeb.basharat]

Car will overheat in D mode also if you start racing and reving uphill and put constant stress on engine.

Nope. You're wrong here! Admit it and let it go.
What are you even talking about? LoL

[dayrider]

He is right, going uphill in D usually adds more stress as there is consistent gear changes. There are other gears in the transmission for this reason.
And fans should kick in when car is overheating, no matter if its negative 50 outside

[daniyalcars72]

yes but they will turn on after longer period of time in subzero temps compared to in a warmer region provided the engine cooling system is in good working condition.

[pwuser150504674948]

Ok then lets hear from Mr.Einstein...

[pwuser150504674948]

Agreed. But in this case going uphill adds considerable stress on the engine leading to heat build up so fans should turn on... the cold temperature is insufficient for cooling at slower speeds uphill.

[pwuser150504674948]

Going uphill in D is ok for crappy CVTs but in regular automatics driving uphill in D feels subpar with unnecessary shifting involved because the car continues to upshift and loose momentum especially at turns. Its not really related to engine heatup though.

I have done Chilas to Babusar route multiple times and have faced a breakdown in a brand new Honda city. The driver being inexperienced was pushing the car to gain speed after every turn, going till 5k rpms before eventually the car overheated. Guess what he was in D.

[aminjafer5441]

I agree. If the car is driven carefully, using any of these modes should be fine when going up a steep slope without overheating.