At what temp do "cold engine" lights go off?

[TmanP]

I was riding in a friend's Civic, which had a blue "cold engine" light. Over a few days, I paid attention to it. I noticed that it went off reaaaally quickly, like within 2 or possibly 3 minutes and maybe a mile (~35-45 degree ambient temp).
In general, what coolant temperature are these programmed to go out at? 120 degrees? 150?
Just thought that this was interesting.

 

[CharBaby]

I'm not familiar with the light.

 

[spasm3]

I'm curious about what temp it takes for them to illuminate. Our mazda cx-5 has one , but i've never seen it lit even at 18 f.

 

[LotI]

My Mazda6 went out at 125F, verified by a ScanGuageII

 

[RamFan]

Originally Posted by spasm3
I'm curious about what temp it takes for them to illuminate. Our mazda cx-5 has one , but i've never seen it lit even at 18 f.


Uh, that's unusual. Does the light even work? I've owned 2 CX-5s and the blue light is always on at start-up regardless of ambient temperature.

This is purely a guess, but I'd say anywhere in the 100-120* area. Figure most vehicles are at OT between 190-220 so maybe when the engine is around halfway to the target?

 

[ARCOgraphite]

My wife has one in the 2017 Subaru Crosstrek with cvt. It usually goes off in about 1 1/2 miles from our house. I tell her to not romp on the throttle till the engine is warm. But I'm sure she does when I'm NOT the car riding shotgun

Cant blame her too much; it appears her engine has VERY aggressive programmed throttle tip in. Just drove it for the first time after doing an OCI today in the icy cold driveway.

My Valentine gift to her!

 

[555]

Depends on vehicle.

 

[y_p_w]

Not sure exactly it works. Is it measuring temp of the coolant or of the engine block? Most of the time I judge it via the coolant temp gauge. I know it's indirect but it's close enough. I remember hearing about several variable valve timing systems that used a coolant temp sensor to determine whether or not they would engage.

There are of course many variables. I thought that typically the engine temp cools down slower than the coolant temp which is exposed to the radiator. I've started a car where the coolant temp was almost like a cold start, but I shut it down an hour earlier. The coolant temp seemed to go up quickly as I drove it. Often if I checked it the engine was still warm to the touch, but the radiator was already at ambient temps. I've also got an all aluminum radiator which cools faster, but obviously doesn't if there's no coolant flow. Also possibly a block heater which will mostly heat up a small portion of the coolant and maybe keep the block a bit warmer.

 

[Linctex]

The old Chevy's in the 60's with a "cold" light went out at 120*F

 

[jc1112]

my Mazda 3 'light' goes out at 132*f

 

[y_p_w]

So thinking about this, I guess they've put these in some cars in place of a coolant temp gauge? I remember renting a few cars (corporate rental only allowed for a basic economy car) where I noticed a cold engine light. Isn't it really just monitoring the coolant temp?

 

[blupupher]

My Scion has one, no idea when it turns off, it is off to the side a bit so I don't notice it.

 

[PimTac]

Originally Posted by y_p_w
So thinking about this, I guess they've put these in some cars in place of a coolant temp gauge? I remember renting a few cars (corporate rental only allowed for a basic economy car) where I noticed a cold engine light. Isn't it really just monitoring the coolant temp?




Mazda provides both but you have to select the info screen option that shows the actual coolant temp. The blue light is just a visual reminder to take it easy until it goes off.

 

[madeej11]

A couple of Toyotas I've had were at 130-132 F.

 

[StevieC]

Usually around 100F more or less. The current vehicle I drive doesn't have one but I always wait until it has at least 100F water temperature before driving away conservatively.

I never floor it unless it has been at full operating temperature for at least 10 minutes of driving so I know the oil is warmed up as well. Luckily I can monitor oil temps in the van.

 

[bullwinkle]

My xB one goes off at a coolant temperature of 140F, assuming it's from the sensor that is connected to the PCM up by the thermostat housing.

 

[Rand]

subaru has very Aggressive throttle tip in.

for example.. 20% is 50% power.
Was quite stupid. it was 100% designed to feel like you had more power than you do.

20% made the throttle body open so much it was passing about 50% of the air it would at full throttle.

they needed a curve vs a straight line.
ie
10% gas pedal opened 5% throttle body

20% opens 10%

30% opens 17%

40% opens 25%


Because the throttle body % opening does not equal air flow %.


made driving stick annoying sometimes.. since there is no torque converter to smooth the ride.
combined with the idle differences when the a/c was on and off.
Where you get the subaru bounce effect too.

You could adapt to all of it.. but wasnt the best. I had mine tuned to change the throttle tables and it was NIGHT AND DAY difference.

 

[Trav]

110-120f coolant temp seems to be the region the light goes off on most car that use them and automatic transmissions can go into top gear

 

[SubieRubyRoo]

I think the Subaru manual says the light goes off at 130*F as well.

 

[69GTX]

At 100-130 deg F coolant temp following initial startup the engine oil is far from warmed up. Engine oil needs to get to 170-180 deg F....and typically lags coolant temperature. A few members did some self studies in the past and found that at moderate ambient temps of 45-65 deg F it would take 15-20 miles of driving or approx 15-20 min of time to fully warmup your engine oil. High revving when coolant temp is 130-160 deg F doesn't seem to make good sense....especially since the oil anti-corrosion/wear additives don't fully kick in until 170-180 deg F. For higher revving I'd rather see engine oil temp up around 195-215 deg F.